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• Description
• Aims and Scope
• Editorial Board
• Abstracting / Indexing
• Submission Guidelines

Waste Management & Research : The Journal for a Sustainable Circular Economy (WM&R)   satisfies the growing demand for scientifically based essential information that can be utilised by waste management professionals in academia, government, industry, engineering, management, planning, and public health.

WM&R is a fully peer-reviewed international journal that publishes original research and review articles relating to both the theory and practice of waste management and research.

The editorial group seeks to promote innovation and provide a bridge between academic studies and practical problems. Articles should address problems and solutions that are of general interest to readers. Electronic access : Waste Management & Research: The Journal for a Sustainable Circular Economy? is available to browse online .

This journal is a member of the Committee on Publication Ethics (COPE)

Routine human activities impact the environment and the consumption of natural materials and energy resources. The challenge to society is to minimize these impacts, maintain an acceptable quality of the environment, and sustain the quality of life and resource supplies for future generations. The generation of solid wastes is inevitable because all products have an end of life and humans and animals create wastes that have to be managed to maintain hygienic, healthy and tidy urban and open country environments. A key objective of the Waste Management and Research. The Journal for a Sustainable Circular Economy (WM&R) is to address these challenges through dissemination of scientifically based reliable information, e.g. in terms of waste prevention, waste recycling, recovery of energy from material residuals not suited for recycling or reuse, waste treatment, and waste disposal.

WM&R is a peer-reviewed journal that satisfies the growing demand for new and scientific information that can be referenced by waste management professionals in academia, government, industry, planning, engineering, management and operation. WM&R presents original work in the form of review articles, original articles, short articles, and letters to the editor.

WM&R encourages the submission of well organized manuscripts relating to sustainable waste management designs, operations, policies or practices and those addressing issues facing both developing and developed countries. Mass flow analyses, life cycle assessments, policy planning and system administration, innovative processes and technologies and their engineering features and cost effectiveness are among the key issues that WM&R seeks to cover through well documented reports on new concepts, systems, practical experience (including case studies), and theoretical and experimental research work. Manuscripts with limited scope or specialised application are normally not accepted. Studies on testing and characterisation of special waste streams or products with only a peripheral pertinence to solid waste management are normally referred to journals that focus on such topics. Manuscripts about modelling and software development are acceptable, when model and software applications remain accessible in the public domain. It is imperative that manuscripts are well founded in terms of existing literature and knowledge, including both recent and older publications.

Peer reviewers and editors evaluating manuscripts for publication consider as key criteria; originality, novelty and applicability of results in theory and/or in practice. Articles must be clearly written in UK English and authors must avoid duplication of information already published and avoid citing opinions without referenced foundations. Strict compliance with these and other WM&R manuscript submission guidelines is necessary to trigger the peer review process that could lead to subsequent acceptance for publication.

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• Preparing your manuscript
• How to submit your manuscript
• After editor acceptance of your manuscript
• How to become a more successful author
• Further information

Waste Management & Research: The Journal for a Sustainable Circular Economy (WM&R) satisfies the growing demand for scientifically based essential information that can be utilised by waste management professionals in academia, government, industry, engineering, management, planning, and public health.   WM&R is a fully peer reviewed international journal that publishes original research and review articles relating to both the theory and practice of waste management and research. In this regard, Editors are obliged to avoid acceptance of plagiarized manuscripts. Instead the Editorial Group seeks to promote innovation and provide a bridge between academic studies and practical problems. Articles should address problems and solutions that are of general interest to the readers.   Waste Management & Research strongly encourages authors to include additional materials alongside their articles. These may take the form of datasets, images, graphical abstracts, tables, audio, and video. For more information on submitting supplementary files, please refer to these guidelines here .   WM&R also encourages authors to share their research data in a suitable public repository subject to ethical considerations and where data is included, to add a data accessibility statement in their manuscript file. Authors should also follow data citation principles. For more information please visit the Research Data Sharing Policies , which includes information about Sage’s partnership with the data repository Figshare.   WM&R also offers optional open access publishing via the Sage Choice programme. The Article Processing Charge (APC) is $3,000, however, you may be eligible for a discount. For more information please visit the  Sage Choice website. For information on funding body compliance, and depositing your article in repositories, please visit  Sage Publishing Policies  on our Journal Author Gateway.    Guidance for the preparation and submission of your manuscript is given below. More detail is available by using the links provided in the text where appropriate.  

1. Preparing your manuscript

1.1 Manuscript peer reviewing and acceptance policy All manuscripts are reviewed initially at the Editorial Office and then by the Associate Editors. Only manuscripts that meet the scientific and editorial standards, and fit within the Aims and Scope of the journal, will be sent for outside peer review. Each manuscript that is sent for peer review is reviewed by a minimum of two independent reviewers.

Be advised that WM&R receives many manuscripts. In order to offer both peer reviewers and editors fair and reasonable workloads, manuscripts uploaded by authors must comply strictly with the WM&R manuscript guidelines, for example in terms of substance, structure and language.

WM&R operates a single-blind reviewing policy in which the peer reviewers’ names are always concealed from the submitting author. Authors are requested to suggest the names, affiliations and contact information of five individuals who may suitably serve as peer reviewers (also known as referees). The suggested reviewers should preferably represent international expertise, and not in any way be associated to the authors or the reported work. The Editors are under no obligation to use all or any of these individuals as reviewers.

1.2 Manuscript Format

All Tables and Figures should form part of the submitted manuscript. They should not be submitted separately. Characters specified below include Tables and Figures, but not References.

• Review articles:  Between 70,000 and 80,000 characters (with spaces), including up to 10 illustrations and/or tables. A review article presents a critical evaluation of information that has already been published, and considers the progress of current research toward clarifying a stated problem or topic. It should meet both of the following criteria: ◦Cite at least 100 references; and ◦Review must appear as a word in the title, and the abstract must state that it is a review article

• Mini-review articles:  Between 40,000 and 50,000 characters (with spaces), including up to 7 illustrations and/or tables. A mini-review article presents a critical evaluation of information that has already been published in a topic related to waste management, and considers the progress of current research toward clarifying a stated problem or topic. It should meet both of the following criteria: ◦Cite at least 50 references; and ◦Mini-review must appear as a word in the title, and the abstract must state that it is a mini-review article

• Original articles:  Between 25,000 and 35,000 characters (with spaces), including up to 7 illustrations and/or tables. An original article presents new information on a specific waste management and research topic or problem. Novel concepts, proven results and interesting perspectives for waste management in theory or practice and evidence of thorough literature research are important criteria when considering acceptability for peer review.

• Short communications:  Between 10,000 and 15,000 characters (with spaces), including up to 4 illustrations and/or tables. A short communication would typically describe topical and/or innovative preliminary data in the field of waste management which may be of interest to an international professional audience and that is deemed worthy of expedited publication.

• Letters to the Editor: Between 3,000 and 3,500 characters (with spaces), including (optional) one figure or table. Letters to the editor must be concise and specific and relate to an already published article in WM&R or to the journal’s operations. Letters to the Editor should be sent directly to the Editor-in-chief ( [email protected] ) and copied to the WMR Editorial Office ( [email protected] ).

• Editorials: Between 8,000 and 9,000 characters (with spaces), including (optional) one figure or table. Editorials address topics that editors or invited guest editors deem of particular concern or general interest.

Authors are asked to prepare their manuscript in Arial 12 point font. Further details on format, layout, and structure are outlined below.

1.3 Manuscript structure (original articles and short reports): In general, authors are encouraged to review and mimic the format and style of previously published WM&R manuscripts. Further guidance is provided below.

Title page: The first page should indicate the title, the authors' names in full and affiliations, and a postal and e-mail address for the corresponding author.

Abstract : Each manuscript should begin with a single-paragraph abstract of max. 1,500 characters (with spaces). The abstract should summarise all aspects of the manuscript [problem(s) addressed, objective(s), methodologies, important result(s), and conclusion(s)].

Key words: For indexing purposes, a list of 6-8 key words is essential. Key words should include important nouns cited in the title and abstract. If in doubt how to select proper key words you may consult “How to become a more successful author” or http://www.uk.sagepub.com/authors/journal/readership.sp

Introduction: A short introduction should start the substantive text. The introduction must place the work described in an appropriate context, including impetus for the research, practical applications (including estimates of costs, where applicable), and results of a literature study. The introduction must clearly state the specific objectives of the work presented.

Materials and methods: This section should describe and reference the techniques applied in the investigation and make clear the protocol of the study. The model and sensitivity of monitoring equipment should be stated in this section. Statistical tests should be described briefly.

Results and discussion: This section should describe what was found and provide appropriate numerical and statistical support. The discussion should explore the implications of the findings but not be highly speculative. It may be convenient to organise the text under sub-headings (not to be numbered).

Conclusion: This section should tie the major findings to the objective(s) stated in the introduction and suggest the practical or theoretical relevance of the manuscript to future research, waste management practices, or regulations and policies.

Acknowledgements: Please acknowledge contributors and sponsors to your work. Formatting and other guidance are set forth at http://www.uk.sagepub.com/authors/journal/funding.sp

1.4 Manuscript style & format

File types The Manuscript should be written as editable/source files only e.g. Microsoft Word (.doc or .docx). Tables, figures and captions/legends should be embedded in the text where they naturally belong. Manuscripts should be in UK English as in the Oxford English Dictionary (OED) and be double line spaced. In general, grammar, punctuation, and syntax for body text should be in accordance with common English practice, such as set forth in the EU English Style Guide.

Text preparation The text should be double-spaced throughout and with a minimum of 3cm for left and right hand margins and 5cm at head and foot. Text should be standard 10 or 12 point.

Illustrations and tables Original line drawings and photographs must be twice the desired size (maximum printed width 130 mm) at a resolution of at least 300 dpi. Remember that text and symbols should be legible in print. The default is to print all graphics in black and white; colour printing is optional at authors' expense. All illustrations should be in “ .jpg” format.

All figures must be numbered consecutively with concise descriptive captions and legends provided on separate pages. Each figure must be clearly referenced in the text (e.g. Fig. 4) and with an indication of where it should appear in the final document (e.g.: Table 4 here).

Authors are responsible for obtaining and submitting to WM&R permission from copyright holders for reproducing any illustrations, tables, figures or lengthy quotations previously published elsewhere.

Units, abbreviations, symbols and equations Only metric units (SI) should be used in a manuscript. After the first appearance of a term in full, a standard abbreviation may be used. Superscripts, not slashes (/), should be used to describe units, e.g. kg m-3.

Equations: Equations should be numbered consecutively and referenced in the text (e.g. Eq. 1), for example Am = B + C (1)

English Language Editing services Non-English speaking authors who would like to refine their use of language in their manuscripts might consider using a professional editing service or including a native-English-speaker as a co-author.

Footnotes Essential information must be included in the text: authors should not use footnotes.

References Please refer to Sage Harvard reference style. View the Sage Harvard guidelines to ensure your manuscript confirms to this refence style.

References should be listed in alphabetical order and appear at the end of the manuscript. Citations in the text should be denoted with the author's surname and the year of publication (e.g.: using the data obtained by Parkpain et al. (2000) or using data from literature (Grigg 1996, Pokrajac and Jones 2000).

If the text contains two or more papers written by the same author(s) in the same year, the citations should be differentiated by a letter; e.g.: (Grigg 1996a). IMPORTANT: Abbreviated journal titles should not be used. Titles of papers should be given in their original language and, if possible, they should be followed by a translation into English in parentheses.

All cited references are to be included in the reference list; and respectively, all listed references are to be cited in the manuscript.

• Book example: Sifaleras A and Petridis K (eds) Operational Research in the Digital Era – ICT Challenges . Cham: Springer.  
• Book chapter example: Gayialis SP, Konstantakopoulos GD and Tatsiopoulos IP (2019) Vehicle routing problem for urban freight transportation: A review of the recent literature. In: Sifaleras A and Petridis K (eds) Operational Research in the Digital Era – ICT Challenges . Cham: Springer, 89-104.  
• Conference Proceedings example: Pokrajac D and Jones K (2000) Oil infiltration in the vicinity of a shallow groundwater table. In: Groundwater 2000. Proceedings of the International Conference on Groundwater Research  (eds Bjerg PL, Engesgaard P & Krom TD), Copenhagen, Denmark, 6-8 June 2000, pp. 17-18. Rotterdam: AA Balkema  
• OnlineFirst example: Velasco E and Nino J (2014) Recycling of aluminium scrp for secondary Al‐Si alloys. Waste Management & Research . Epub ahead of print 1 September 2014. DOI: 10.1177/0734242X10381413.  
•  Scientific journal example: Parkpain P, Sreesai S and Delaune RD (2014) Bioavailability of heavy metals in sewage sludge amended Thai soils. Water, Air and Soil Pollution 122(1): 163-182.  
• Web site reference example: National Center for Professional Certification (2002) Factors affecting organizational climate and retention. Available at: www.cwla.org./programmes/triechmann/2002fbwfiles (accessed 10 July 2010).  
• Scientific report example: HLPE (2014) Food losses and waste in the context of sustainable food systems. A report by the High Level Panel of Experts on Food Security and Nutrition of the Committee on, World Food Security, Rome.

United Nations Environment Programme (UNEP) and United Nations Industrial Development Organization (UNIDO) (1991) Audit and reduction manual for industrial emissions and wastes. Technical report UNEP(05)/T32. Paris: UNEP.

WHO (World Health Organization) (2020a) Coronavirus disease 2019 (COVID-19) situation report 51. Available at: https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200311-sitrep- 51-covid-19.pdf?sfvrsn=1ba62e57_10 (accessed 20 March 2020).

1.5 Plagiarism Policy

Waste Management & Research and Sage take very seriously issues of copyright infringement, plagiarism or other breaches of best practice in publication. We seek to protect the rights of our authors and we always investigate claims and/or evidence of plagiarism or misuse of published articles. Equally, we seek to protect the reputation of the journal against malpractice. To this end, submitted articles may be checked using duplication-checking software. Where an article, for example, is found to include material plagiarised from other works or third-party copyright material without permission or with insufficient acknowledgment, or where the authorship of the article is contested, we reserve the right to take action. Actions may include, but not be limited to: publishing an erratum or corrigendum (correction); retracting the article: taking up the matter with the head of department or dean of the author's affiliated institution and or/relevant academic bodies or societies; or taking appropriate legal action.

1.6 Research Data

The journal is committed to facilitating openness, transparency and reproducibility of research, and has the following research data sharing policy. For more information, including FAQs please visit the Sage Research Data policy pages .

Subject to appropriate ethical and legal considerations, authors are encouraged to:

• share your research data in a relevant public data repository
• include a data availability statement linking to your data. If it is not possible to share your data, we encourage you to consider using the statement to explain why it cannot be shared.
• cite this data in your research

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2. How to submit your manuscript

Before submitting your manuscript, please carefully read and adhere to all the guidelines and instructions to authors provided above. Manuscripts not conforming to these guidelines may be returned.

Online submission and review for all types of manuscripts excluding Letters to the Editor is mandatory. Please use the Sage track website http://mc.manuscriptcentral.com/WMR to open an account as author and follow the guidelines for uploading of manuscripts.

IMPORTANT: Please check whether you already have an account in the system before trying to create a new one. If you have reviewed or authored for the journal in the past year it is likely that you will have already created an account. For further guidance on submitting your manuscript online please visit ScholarOne Online Help [email protected]

Account for new users Please log onto the website. If you are a new user, you will first need to create an account. Follow the instructions and please ensure that you have entered a current and correct e-mail address. Creating your account is a three-step process that takes only a couple of minutes. When you have finished, your User ID and password are sent via e-mail immediately. Please edit your User ID and password to something more memorable by selecting 'edit account' at the top of the screen. If you have already created an account but have forgotten your details, type your e-mail address in the 'Password Help' to receive an e-mailed reminder. Full instructions for uploading the manuscript are provided on the website.

ORCID As part of our commitment to ensuring an ethical, transparent and fair peer review process Sage is a supporting member of ORCID, the Open Researcher and Contributor ID . ORCID provides a unique and persistent digital identifier that distinguishes researchers from every other researcher, even those who share the same name, and, through integration in key research workflows such as manuscript and grant submission, supports automated linkages between researchers and their professional activities, ensuring that their work is recognized. 

The collection of ORCID iDs from corresponding authors is now part of the submission process of this journal. If you already have an ORCID iD you will be asked to associate that to your submission during the online submission process. We also strongly encourage all co-authors to link their ORCID iD to their accounts in our online peer review platforms. It takes seconds to do: click the link when prompted, sign into your ORCID account and our systems are automatically updated. Your ORCID iD will become part of your accepted publication’s metadata, making your work attributable to you and only you. Your ORCID iD is published with your article so that fellow researchers reading your work can link to your ORCID profile and from there link to your other publications.

If you do not already have an ORCID iD please follow this link to create one or visit our ORCID homepage to learn more.

New Submission Submissions should be made by logging in and selecting the ‘Author Center’ and the 'Click here to ‘Submit a New Manuscript' option. Follow the instructions on each page, clicking the 'Next' button on each screen to save your work and advance to the next screen. If at any stage you have any questions or require the user guide, please use the 'Get Help Now' button at the top right of every screen. Further help is available through ScholarOne's® Manuscript CentralTM customer support at +1 434 817 2040 x 167 (between 09 and 16 GMT).

To upload your manuscript, click on the 'Browse' button and locate the files on your computer. When you have selected the file you wish to upload, click the 'Upload Files' button.

Check that your submission is as intended (in .docx format) and then click the ‘Submit’ button. You may suspend a submission at any point before clicking the Submit button and save it to submit later. After submission, you will receive a confirmation e-mail. You can also log back into your author centre at any time to check the status of your manuscript.

If you would like to discuss your paper prior to submission, please contact the Senior Editor-in-Chief at: [email protected] For advice on the submission process, please contact the Editorial Office Manager at: [email protected] .

Submitting a Revised Submission Authors submitting revised manuscripts should follow the instructions above to submit through the Sage track system. To create a revision, go to the 'Manuscripts with Decisions' option in your Author Dashboard and select Create a revision’ in the 'Action' column. Authors of all revised submissions should, when prompted, provide information explaining the changes in their manuscript.

Time for processing of your manuscript WM&R manuscript processing implies a period of time between submission and acceptance of manuscript that is typically 4-6 months, depending on the quality of the manuscript. Author and editor can shorten the necessary period by appropriate and speedy action when assessing the reviewers’ comments (editor) and when revising the manuscript accordingly (author).

After possible acceptance of your manuscript by the editor, you may expect Online First (OF) publication by Sage within approximately 1.5 months, given immediate and complete response from you when receiving proofs from Sage. Printed publication will take place later depending on organisation and focus of topics in the different upcoming issues of WM&R and the number of manuscripts already in the pipeline for printing. You will be notified in advance, but OF publication facilitates immediate journal citation and complete referencing due to the DOI number that will always follow your article in both OF and printed versions.

3. After editor acceptance of your manuscript

Journal contributor’s publishing agreement       Before publication Sage requires the author as the rights holder to sign a Journal Contributor’s Publishing Agreement. Sage’s Journal Contributor’s Publishing Agreement is an exclusive licence agreement which means that the author retains copyright in the work but grants Sage the sole and exclusive right and licence to publish for the full legal term of copyright.  Exceptions may exist where an assignment of copyright is required or preferred by a proprietor other than Sage. In this case copyright in the work will be assigned from the author to the society. For more information please visit our Frequently Asked Questions on the Sage Journal Author Gateway at http://www.sagepub.com/journalEditors.nav

WM&R offers optional open access publishing via the Sage Choice programme. The Article Processing Charge (APC) is $3,000, however, you may be eligible for a discount. For more information please visit the  Sage Choice website . For information on funding body compliance, and depositing your article in repositories, please visit  Sage Publishing Policies  on our Journal Author Gateway. 

Proofs Sage will email a .pdf of the proofs to the corresponding author.

E-Prints  Sage provides authors with access to a .pdf of their final article. For further information please visit http://www.sagepub.co.uk/authors/journal/reprint.sp .  

Sage Production At Sage we place an extremely strong emphasis on high quality production standards. We attach high importance to our quality service levels in copy-editing, typesetting, printing, and online publication ( http://online.sagepub.com/ ). We also seek to uphold excellent author relations throughout the publication process.

We value your feedback to help us continue to improve our author service levels. On publication all corresponding authors will receive a brief survey questionnaire about your experience of publishing in WM&R with Sage. 

OnlineFirst Publication WM&R benefits from OnlineFirst, a feature offered through Sage’s electronic journal platform, Sage Journals Online. It allows final revision articles (completed articles in queue for assignment to an upcoming print issue) to be hosted online prior to their inclusion in a final print and online journal issue which significantly reduces the lead time between submission and publication. For more information please visit our OnlineFirst Fact Sheet

4. How to become a more successful author

The WM&R editors have developed a set of criteria for how to produce well written articles and become successful authors. Authors are advised to follow these guidelines:  How to be a more successful author

For more information, follow this link:  https://www.sagepub.com/how-to-get-published

5. Further information

If you would like to discuss your paper prior to submission, or seek advice on the submission process please contact the Senior Editor-in-Chief at this email address: [email protected] . For advice on the submission process, please contact the Editorial Office Manager at: [email protected] .

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Waste Management & Research

The journal for a sustainable circular economy, iswa’s monthly scientific journal (if 3.9).

The Waste Management & Research (WM&R) is ISWA’s monthly peer reviewed scientific journal that satisfies the growing demand for new and scientific information for reference by waste management professionals in academia, government, industry, planning, engineering, management and operations. WM&R presents original work in the form of review articles, original articles, short articles, and letters to the editor. The detailed description, aims and scope of WM&R can be read here .

In the 2022 Journal Citation Report, published in June 2023, WM&R’s Impact Factor was reported at 3.9. The Impact Factor indicates the frequency on citations of articles published in the journal. Overall, the journal is continuing to see an increase in citations compared to the previous year.

WM&R can be freely accessed by ISWA members (excluding Online Members) at the right side of this page. Non-members can freely access Editor’s Choice papers , which consist of some of WM&R’s best papers, selected from each Issue by the Editor. Abstracts are freely accessible as well.

A Special Issue of WM&R has been published for every ISWA World Congress since 2012. These Special Issues include papers presented at the World Congress, please find an index of the ISWA World Congress and other Special Issues here .

The Editorial Group (EG) is responsible for the editorial management of WM&R and consists of the Senior Editor-in-Chief, two Editors-in-Chief and 6 Associate Editors. The WM&R Editorial Group is supported by Fran Saint-Geris (Senior Publishing Editor) at SAGE and Gazel de Klerk (Editorial Office Manager) at ISWA.

The Editorial Board supports WM&R through frequent review of papers and active contribution to WM&R’s strategy. WM&R’s International Advisory Board consists of senior experts who have taken an advisory role in shaping the journal’s development. For a complete list of the members of WM&R’s Editorial Group, International Advisory Board and Editorial Board please click here .

To submit an article, see the manuscript preparation and submission guidelines .

For any questions about WM&R, please contact the WM&R Editorial Office through the contact form below.

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WM&R Journal Access

ISWA Members (except Online) have full access to the Waste Management and Research Journal. If you would like to access the Journal, please log in or become a member.

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Waste Management

EPA researchers develop methods for managing solid waste and contaminated water resulting from natural and human-made disasters, including waste minimization, treatment, storage and disposal. Researchers also develop tools and information to support waste management decisions. 

Natural disasters are occurring with increasing frequency, generating volumes of waste and debris that are difficult for states, local governments, tribes and territories to manage. Waste management presents considerable challenges during any large-scale disaster; additional challenges exist during a wide-area chemical, biological, radiological, or nuclear (CBRN) incident. 

Waste management challenges include:

• minimizing the amount of waste generated during cleanup
• segregating waste types
• waste treatment options
• temporary waste storage & staging
• packaging and transporting waste
• disposing of waste and debris
• treatment and disposal options for contaminated water

Throughout the incident response and clean up, waste must be characterized  to reduce human exposure to contamination and to  determine how and where to ship, treat and/or dispose of contaminated materials . 

Response to a large-scale incident is complex because activities are interrelated.  For example, decontamination approach decisions have an impact on the timeline of cleanup as well as on the cost and overall amount of waste generated. Decision-makers must be aware of the trade-offs involved in their decisions to optimize the response. 

For CBRN incidents these complexities are compounded by:

• Lack of a federal regulations for managing biologically-contaminated waste
• Limited disposal capacity for radiologically contaminated waste
• Lack of experience of  decision-makers and waste management facilities in handling these wastes
• Hesitancy from some disposal facilities to accept these wastes
• Research Topics
• Solid Waste
• Water Treatment and Waste Management
• Materials and Waste Management Research (non-CBRN specific)

Available Tools

• Waste Estimation Support Tool (WEST) : aids in estimating waste generated from remediation and cleanup activities following a radiological or biological incident.
• Incident Waste Assessment & Tonnage Estimator (I-WASTE) : provides information for planning how to handle, transport, treat, and dispose of contaminated waste and debris. Includes a waste volume calculator.
• Municipal Solid Waste Decision Support Tool (MSW DST) : can be used to identify and evaluate cost and environmental aspects associated with specific waste management strategies or existing systems. 
• Decision Support Tools for Incident Response & Waste Management : access a page with a suite of EPA tools to support many response-related tasks. Use the filters to quickly find tools that are specific to hazards and/or response activities/phases. 

Other Resources

• Video: Incident Waste Assessment & Tonnage Estimator (I-WASTE)
• Managing Materials and Wastes for Homeland Security Incidents
• Sustainable Materials Management Tools

Featured Science Matters Stories

EPA Tools Help Local Decision-Makers Deal with Waste Resulting from Major Natural Disasters

• Emergency Response Research Home
• Models, Tools, & Applications
• Outreach & Training
• Publications

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• Published: 23 March 2020

Evidence synthesis for tackling research waste

• Matthew J. Grainger   ORCID: orcid.org/0000-0001-8426-6495 1 ,
• Friederike C. Bolam   ORCID: orcid.org/0000-0002-2021-0828 2 ,
• Gavin B. Stewart   ORCID: orcid.org/0000-0001-5684-1544 2 &
• Erlend B. Nilsen   ORCID: orcid.org/0000-0002-5119-8331 1  

Nature Ecology & Evolution volume  4 ,  pages 495–497 ( 2020 ) Cite this article

1901 Accesses

23 Citations

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Metrics details

• Biodiversity
• Conservation biology
• Ecological modelling
• Scientific community

There is an immediate need for a change in research workflows so that pre-existing knowledge is better used in designing new research. A formal assessment of the accumulated knowledge prior to research approval would reduce the waste of already limited resources caused by asking low priority questions.

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We thank H. Fraser and J. Eales for their insightful comments on our commentary which has greatly improved the final version.

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Biochar from co-pyrolysis of biological sludge and woody waste followed by chemical and thermal activation: end-of-waste procedure for sludge management and biochar sorption efficiency for anionic and cationic dyes

• Research Article
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• Published: 09 May 2024

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• Zaineb Bakari 1 , 2 ,
• Michelangelo Fichera 1 ,
• Ayoub El Ghadraoui 1 ,
• Lapo Renai 1 ,
• Walter Giurlani 1 ,
• Daniela Santianni 3 ,
• Donatella Fibbi 4 ,
• Maria Concetta Bruzzoniti 5 &
• Massimo Del Bubba   ORCID: orcid.org/0000-0002-6326-6549 1  

Nine biochars were produced by co-pyrolysis of sawdust and biological sludge following the “design of experiment” approach. Two kinds of sludge (both deriving from the treatment of mixed industrial-municipal wastewater) and two types of woody waste were selected as categorical predicting variables, while contact time, pyrolysis temperature, and sludge percentage were used as quantitative variables. Biochars were analysed for their product characteristics and environmental compatibility based on the European Standards (EN 12915–1:2009) for materials intended for water treatment (i.e. ash content, water leachable polycyclic aromatic hydrocarbons (PAHs) and elements), as well as for specific surface area (SSA), using them as response variables of a multivariate partial least square multiple regression, whose results provided interesting insights on the relationships between pyrolysis conditions and biochar characteristics. Biochars produced with sludge and/or providing the highest SSA values (258–370 m 2  g −1 ) were selected to undergo a sustainable chemical treatment using a by-product of the gasification of woody biomass, complying in all cases with European Standards and achieving therefore the end-of-waste status for sewage sludge. The biochar deriving from the highest percentage of sludge (30% by weight) and with the highest SSA (390 m 2  g −1 ) was thermally activated achieving SSA of 460 m 2  g −1 and then tested for the sorption of direct yellow 50 and methylene blue in ultrapure water and real wastewater, compared to a commercial activated carbon (AC). The biochar showed Langmuir sorption maxima ( Q m ) 2–9 times lower than AC, thus highlighting promising sorption performances. Q m for methylene blue in wastewater (28 mg‧g −1 ) was confirmed by column breakthrough experiments.

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Introduction

The quality of surface water (SW), as well as that of wastewater treated for reuse, is increasingly compromised by the presence of organic micropollutants of both domestic and industrial origin. Within this latter category of micropollutants, synthetic dyes are structurally heterogeneous compounds widely used in many manufacturing applications, mainly related to textile industry (Sabnis 2017 ). Synthetic dyes are generally characterized by a significant toxicity towards humans and environment, which is expressed in most cases through their degradation products, rather than by the parent molecule. For example, the toxicity of azo-dyes occurs through the reduction and cleavage of the azo linkage to give aromatic amines that are metabolically oxidized to reactive electrophilic species, capable to covalently bind DNA, or via direct oxidation of the azo group to highly reactive electrophilic diazonium salts (Brown and Vito 1993 ). Accordingly, adsorption techniques may play an important role in the removal of dyes from wastewater since they do not provide any modification of the structure of the molecule during the treatment.

Both well-established materials (i.e. commercial activated carbons) (Azari et al. 2020 ) and novel sorbents (e.g. polymer-derived silicon carbide foams and aerogels and various kinds of nanocomposites) (Bruzzoniti et al. 2018a , 2018b ; Srivastava et al. 2020 ) have been tested for the removal of dyes from water matrices. Among sorbents intended for wastewater treatment, biochar has received increasing attention as a low-cost material obtained from the thermochemical conversion (i.e. pyrolysis or gasification) of a wide variety of waste vegetal biomass and/or biosolids (Ghodake et al. 2021 ). Biochar is a porous material containing crystalline (i.e. graphene-like) and amorphous carbonized fractions, as well as non-carbonized phases, which may comprise aromatic and aliphatic portions linked with groups at different polarity (Inyang &Dickenson 2015 ). According to literature, biochars exhibit a wide range of physical and chemical characteristics, depending on the thermochemical conversion process, the temperature, the contact time, and the feedstock used for their production (Castiglioni et al. 2021 ). Moreover, various modifications and/or engineering of biochars (e.g. chemical and physical activation, metal impregnation, and functionalization) have been tested in order to enhance their sorption efficiency towards micropollutants in water matrices (Liu et al. 2015 ; Tan et al. 2017 ). Among the waste biomass used as feedstock for biochar production, biological sludge from wastewater treatment plants (WWTPs) represents an attractive option. Biological sludge is in fact a widely available waste material characterized by a high environmental hazard, the disposal of which involves a high cost, while its reuse is consistent with the modern approach to the waste management and the circular economy (European Parliament and the Council of the European Union 2018 ), thereby ensuring great savings. It is also noteworthy that thermochemical conversion of biological sludge into biochar, which takes place at temperatures above about 400 °C, allows to inhibit the intrinsic toxicity linked to the presence in this matrix of poorly biodegradable organic micropollutants and potentially pathogenic organisms (i.e. viruses and bacteria). Therefore, it is clear that the conversion of biological sludge into biochar to be used as sorbent in WWTPs may be a doubly successful strategy to achieve more efficient sludge management and better environment protection. The use of biological sludge, alone (Singh et al. 2020 ) or mixed with waste vegetal biomass (Chen et al. 2019 ; Zhang et al. 2020a ), has recently been investigated for the production of biochar in some researches. Nevertheless, the thermal conversion of biological sludge from industrial wastewater treatment to biochar is poorly described in the literature (Kwon et al. 2020 ). Sludge-based biochars usually exhibit values of specific surface area (SSA) and sorption properties much lower than commercial activated carbons (Castiglioni et al. 2021 ), the latter considered the material of choice for the removal of micropollutants in wastewater and drinking water (Del Bubba et al. 2020 ). Hence, biochars are often modified and/or engineered following different approaches (e.g. chemical and physical activation, metal impregnation, and synthesis of biochar-derived nanocomposites), in order to enhance their adsorption properties (Cheng et al. 2021 ). However, engineered biochars have their own limitations, such as the consumption and/or release of chemicals or nanomaterials potentially hazardous for the environment, as well as higher costs compared to those obtained by thermal conversion only (Lyu et al. 2018 ; Wan et al. 2019 ).

Sludge-based biochars have been tested for the adsorption and the degradation of various micropollutants, mainly metal cations, pharmaceuticals, and dying agents (Singh et al. 2020 ). However, these studies were performed in most cases on ultrapure water solutions, thus limiting their significance. Moreover, the removal performance of biochars is seldom compared with the adsorption capacity of standard activated carbons (Castiglioni et al. 2022 ; Del Bubba et al. 2020 ), with obvious limitations in the reliable evaluation of their sorption performance.

Although to our knowledge there is no legislation regulating the use of biochar and more generally of adsorbent materials in the treatment of wastewater, the EN 12915–1 European Standards regulating the use of adsorbent materials for the treatment of drinking water (European Committee for Standardization 2009 ) can be used as a precautionary approach. This regulation provides legal limits for parameters related to adsorption performances (e.g. ash content) and environmental compatibility (i.e. release of selected metals and polycyclic aromatic hydrocarbons), the latter commonly representing a relevant issue in the use of biochars but very often not evaluated in the literature (Singh et al. 2020 ).

Based on the above-mentioned considerations, the objective of this research was the production and characterization of biochars by co-pyrolysis of mixtures of biological sludge (both from the treatment of mixed industrial-municipal wastewater) and waste woody biomass, under different experimental conditions, set by the experimental design approach (DoE). The biochars have been characterized for some product and environmental compatibility parameters included in the aforementioned European Standards, here considered a precautionary guideline, thus providing new information on the end-of-waste process of biological sludge. These parameters were used in DoE as response variables of a multivariate partial least square multiple regression (PLS). Biochars providing the highest SSA values were treated by chemical and thermal processes to improve their product and environmental compatibility properties and finally characterized in depth. Sorption capacity towards methylene blue (MB) and direct yellow 50 (DY) was determined for biochars better satisfying the European Standards requirements, in comparison with a commercially available virgin activated carbon (AC), commonly employed in WWTPs and potabilization facilities. Ultrapure water and effluent wastewater, the latter collected from a WWTP operating in an industrial textile district, were used for this purpose. In particular, the wastewater used in this study derived from one of the two WWTPs from which the sludge was extracted, allowing to collect new information about the sludge management cycle within this kind of WWTPs. Sorption performances were discussed in relation to physicochemical properties of the materials in order to interpret the removal data obtained. Breakthrough column tests were also carried out with the material having the most promising performance to evaluate MB removal from wastewater.

Materials and methods

Full details of the reagents, standards, and materials used in this research, as well as preparation of stock solutions of target analytes, are reported in section S.1 of the Supplementary material , together with CAS numbers, structure formulas, log K OW values, and maximum absorption wavelengths of the investigated dyes (see Table S1 ). Target analytes are characterized by different charges (− 4 and + 1 for DY and MB, respectively, at pH = 7) and hydrophobicity (log K OW values at pH = 7, equal to − 1.85 and 2.61 for DY and MB, respectively).

Feedstocks used for biochar production

The biological sludge (BSs) and the waste woody biomass (WWBs) used as feedstocks for the production of biochar were supplied by Gestione Impianti di Depurazione Acque S.p.A. (Prato, Italy) and Romana Maceri Centro Italia S.r.l. (Civitella in Val di Chiana, Italy), respectively. More in detail, WWBs were residues from the cutting of two forests in Tuscany (Italy), mainly consisting of oak and poplar, respectively, while BSs derived from Calice and Vernio activated sludge WWTPs (see Table S2 , section S.2 of the Supplementary material for their characterization), mainly treating industrial textile wastewater. The feedstocks were dried at 90 °C for 48 h and then crushed and sieved at 10 mm before being pyrolysed.

Biochar and activated carbons

The biochars were produced via co-pyrolysis of WWBs and BSs mixtures in a muffle furnace (Gefran 1001, Vittadini Strumentazione, Milano, Italy), properly modified to allow the heating process in N 2 -saturated conditions. All materials were pre-treated before being characterized and used in isotherm studies. In detail, the chars were sieved at 45 µm and then repeatedly washed with ultrapure water according to the ASTM D-5919–96 method (American Society for Testing and Material 2022 ).

Design of experiments

The biochars were produced following the DoE approach, through a “reduced combinatorial design” that allowed to balance the number of experiments with the efforts required for the analysis of the multiple parameters, necessary for an in-depth characterization of the sorbents. In this way, it was possible to treat equally qualitative (feedstock and sludge type) and multilevel quantitative (i.e. pyrolysis temperature, contact time, sludge percentage) factors. According to this design, nine biochars (B1–B9) plus three replicates (B3/B10, B8/B12, and B9/B11) were produced under the experimental conditions reported in Table  1 . The aforementioned factors were used for modelling some relevant parameters related to product characteristics (i.e. SSA and ash content) and environmental compatibility (i.e. released of PAHs and selected elements) of the biochars, through the PLS algorithm. Correlation coefficients in fitting ( R 2 ) and prediction ( Q 2 ) ≥ 0.50 were applied as constraints to consider statistically significant the models obtained. The software Sartorius (Stedim Biotech, Aubagne, France) MODDE Pro 13.0 was used for planning the data processing related to the “reduced combinatorial design” and the evaluation of the PLS models.

Char characterization

Elemental analysis.

The C, H, N, S analysis was performed using a FlashEA® 1112 elemental analyser Thermo Fisher Scientific (Waltham, MA) equipped with a thermal conductivity detector (Table S3 of the Supplementary material ). The percentage content of oxygen was estimated as the difference with those of the other elements and ash (Al-Wabel et al. 2013 ). Moreover, the O/C and H/C ratios were calculated and plotted in a van Krevelen diagram (Figure S1 of the Supplementary material ). Full details of the elemental analysis and related calculations are reported in section S.3.1 of the Supplementary material .

Ash content was determined according to the EN 12902:2004 Official Method (European Committee for Standardization 2004 ), which refers to the analysis of products used for the treatment of water intended for human consumption and is adopted in this field for the analysis of activated carbons. Full details of the procedure adopted for the determination of ash content and results obtained are respectively reported in section S.3.2 and Table S4 of the Supplementary material .

Physisorption analysis

Physisorption analysis of biochars was performed via nitrogen adsorption and desorption experiments using a Porosity Analyser Micrometrics (Norcross, GA, USA) model 3Flex (American Society for Testing and Material 2022 ). Total SSA, as well as micropore and mesopore SSA, was determined by the Brunauer–Emmett–Teller (BET), the t-plot, and the Barrett-Joyner-Halenda (BJH) methods, respectively (see section S.3.3 of the Supplementary material for further details).

pH of the point of zero charge

The pH of the point of zero charge (pH PZC ) was determined using the pH drift method, which is a simple and widely used procedure, adopted for the evaluation of the surface charge of both biochars (Chaukura et al. 2017 ) and activated carbons (Niasar et al. 2016 ). Full details of the procedure are reported in section S.3.4 of the Supplementary material , together with the plots obtained for the investigated biochars (Figure S2 ).

Thermogravimetric analysis

Thermogravimetric analysis (TGA) was conducted using a TGA analyser, model EXSTAR 6200, as specified in section S.3.5 of the Supplementary material .

X-ray diffraction analysis

X-ray diffraction (XRD) was performed by using the Bruker (Billerica, MA, USA) New D8 Da Vinci X-ray diffractometer (radiation Cu-Kα1 = 1.54056 Å, 40 kV × 40 mA) equipped with a Bruker LYNXEYE-XE detector (see section S.3.6 of the Supplementary material for further details).

Scanning electron microscopy-energy dispersive X-ray spectroscopy

Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were performed by a Hitachi (Tokyo, Japan) SU3800 SEM equipped with a Silicon Drift EDS Detector, model Ultim Max 40 (Oxford Instruments NanoAnalysis, High Wycombe, UK). For further details, see section S.3.7 of the Supplementary material .

Water-extractable substances

The aqueous extraction of selected elements and PAHs (Table S4 ) was performed according to the EN 12915–1 standard method (European Committee for Standardization 2009), as described in section S.3.8 of the Supplementary material . The analysis of the water-extractable metals was carried out by ICP-MS after microwave digestion, while PAHs were determined by SPE extraction followed by GC–MS analysis. Full details of both analytical protocols and figures of merit are reported in Tables S5 - S7 and Figure S3 (section S.3.8 of the Supplementary material ).

Effluent wastewater used in sorption and column studies

Effluent wastewater from the Calice WWTP was used to evaluate the sorption capacity of the biochar, which has proven to be more efficient in tests with ultrapure water. The characterization of the effluent wastewater for a number of routinely analysed parameters is shown in Table S8 (section S.4 of the Supplementary material ).

Chemical and thermal activation of biochars

The biochars were treated with the BioDea® solution, a commercially available (Bio-Esperia S.r.l., Umbertide, Italy) acidic liquid by-product of the gasification of woody waste (see section S.5 of the Supplementary material for some details of the optimization of the washing protocol and Table S9 for BioDea characteristics) and then thermally activated at 650 °C for 2 h in muffle furnace under N 2 -saturated conditions. These experimental conditions were chosen based on the results obtained in previous studies for the regeneration of chars from coconut shell (Cazetta et al. 2013 ). Activated biochars were dried overnight at 105 °C and kept in a desiccator before use.

Performance evaluation of selected chars as adsorbent materials

The evaluation of the adsorption performances of biochars and AC towards the investigated dyeing agents was carried out by means of kinetic and isotherm tests, measuring the decrease of the absorbance of aqueous solutions of MB (652 nm) and DY (404 nm) in contact with chars by an UV–Vis spectrophotometer HACH (Loveland, CO, USA) DR/4000 U. Full details of the procedures adopted for carrying out these tests are reported in section S.6 of the Supplementary material .

Langmuir and Freundlich equations were used to fit the adsorption isotherms data, as described in section S.6.2 of the Supplementary material .

Breakthrough column tests were also carried out as described in section S.6.3 in order to test the sorption capacity of biochar under experimental conditions closer to those adopted in WWTPs for wastewater refining by filtration on activated carbons.

Data treatment and computational analysis

The construction of the linearized Langmuir and Freundlich models and the evaluation of their statistical significance through the Fisher test was carried out using Microsoft Excel® 2019 (Redmond, WA, USA).

The molecular width of target analytes was calculated after MM2 energy minimization using the Chem3D package, version 12.0.2.1076 (PerkinElmer Informatics, Waltham, MA, USA).

Results and discussion

Evaluation of the biochar characteristics in relation to pls models.

Biochars produced under the experimental conditions described in the screening matrix (Table  1 ) have been characterized for ash content and water extractable trace elements and PAHs (Table S4 ), as parameters regulated by the EN 12915–1 for materials intended for water filtration. Moreover, the total SSA of the investigated materials has also been determined (Table S4 ) since it provides interesting information on the sorption ability (Luo et al. 2022 ). These parameters have been used as response variables in the experiments included in the screening matrix. Values of pH PZC and distribution of the main elements (C, H, N, S, and O) (Table S3 of the Supplementary material ) were also determined on all biochars reported in Table  1 , and van Krevelen diagram (H/C vs. O/C) was plotted (Figure S1 of the Supplementary material ) in order to obtain general information about composition and stability of the biochars produced. However, these data were not included in the group of response variables, since they are not directly related to the environmental compatibility or sorption capacity of carbonaceous materials. Based on the constraints adopted for R 2 and Q 2 values (see Table S10 , section S.7 of the Supplementary material ), statistically significant PLS models were obtained for ash content, As, Ni, Sb, Se, and PAHs release, and SSA. Figure  1 illustrates the scaled and centred PLS model coefficients associated with the multilevel and qualitative production factors (prediction variables), which exerted a statistically significant effect on the aforementioned seven response variables. Considering the values assumed by these coefficients, it is possible to infer their influence on the response variables.

Scaled and centred coefficients of the statistically significant partial least square regression models for the best fitting and prediction of ash content, release of As, Ni, Sb, Se, and PAHs, and specific surface area, based on the following production factors: woody waste type (WWB), sludge type (ST), pyrolysis temperature (PT), contact time (CT), and sludge percentage (SP). WT was mainly oak (A) or poplar (B)

Higher values of sludge percentage (SP) contribute to an increase in the ash content of biochars, even though with different extents by the two sludge types (ST), being the Calice and Vernio coefficients characterized by opposite signs. This finding reflects the high content of inert constituents of sewage sludge used here, particularly that deriving from the Vernio WWTP (see Table S2 ). The ash content also increases with increasing pyrolysis temperature (PT), in accordance with the variations of the yield of biochar reported elsewhere (Castiglioni et al. 2022 ) as a function of this production factor. Conversely, contact time (CT) shows an opposite influence, even though the extent of its contribution is quite low.

Selected elements

Similar to what has been observed for ash, the release of selected elements (i.e. As, Sb, and Se) increases with the percentage of sludge. Moreover, the two types of vegetal biomass and the two sludges showed different contributions, as evidenced by the opposite signs of their coefficients, thus suggesting a lower metal bioavailability for biochar made from oak and sludge of Calice WWTP, compared to those produced from poplar and sludge of Vernio WWTP. The release of elements is also affected by PT (for As, Ni, and Sb) and CT (for Sb and Se), both exhibiting negative coefficients and thus highlighting a lower water extractability in biochar produced at higher PT and CT. Similar results have been found in previously published studies (Devi & Saroha 2014 ; Zhang et al. 2022 ) and explained on the basis of complex phenomena occurring in the material, which involve the decomposition of organic functional groups, the collapse of the pores, and the incorporation of the inorganic species into the new structure formed (Zhang et al. 2022 ). Further possible explanations involve the presence/formation of salts and crystalline phases having basic character that bind the elements, reducing their leachability (Devi &Saroha 2014). This hypothesis is strongly supported by the much higher pH PZC values found for biochars obtained at 650–850 °C, compared to those produced at 450 °C (Table S3 ).

Polycyclic aromatic hydrocarbons

PT and SP significantly affect the release of PAHs, which decreases with the increase of both these parameters. The effect of PT observed here confirms the results elsewhere reported and attributed to the degradation of PAHs already present in the sludge and/or formed during pyrolysis at temperatures up to about 500 °C (Castiglioni et al. 2022 ). The decreasing trend of the release of PAHs with the increase of SP can be explained by the different compositions of the organic fractions of WWB and sludge. In fact, the woody biomass consists almost exclusively of cellulose, hemicellulose, and lignin, well-known precursors of the formation of PAHs during pyrolysis (Wang et al. 2017 ), while the bacterial biomass, made mainly of peptidoglycans and lipids, is less subjected to PAH formation (McGrath et al. 2007 ). The decrease in PAHs release as SP in the feedstock increases is a very interesting result that highlights a further positive aspect of the management of sludge by pyrolysis.

Specific surface area

The feedstock composition and the PT significantly influenced the surface area. In detail, the increase in SP negatively affects the surface area regardless of the ST. Conversely, WWB exerts a different effect depending on the type of biomass, with WWB-A (mainly oak) and WWB-B (mainly poplar) contributing to lower and increased surface area, respectively. Surface area increases by increasing PT, in agreement with findings previously obtained on various types of biochars (Castiglioni et al. 2022 ).

Overall evaluation of pyrolysis conditions

Overall, based on the coefficients reported in Fig.  1 , it is evident that PT and/or SP significantly affected all the seven response variables modelled by PLS. Therefore, it is interesting to evaluate the trend of these response variables as a function of both SP and PT, attempting an optimization of the pyrolysis process. This can be done through the 2D contour plots reported in Figure S4 - S7 of the Supplementary material , where, in each of the four plots, a combination of the categorical variables WWB and ST is selected, while the multilevel factor CT is fixed at 90 min, owing to its lower statistical inference, compared to the other quantitative variables. In these plots, target values represent the EN 12915–1 requirements reported in Table S4 , except for SSA which was fixed at 300 m 2  g −1 based on an overview of literature data (El Barkaoui et al. 2023 ). The examination of the contour plots highlights that in the investigated ranges of the process variables; the behaviour of the seven response variables modelled by PLS is identical for all four possible combinations of feedstocks subjected to co-pyrolysis. Changes in process conditions that improve certain product and/or environmental characteristics of the biochars lead to a worsening of others. For example, when producing biochar at high temperatures and with high sludge percentages, the production and release of PAHs are minimized, but at the same time, ash percentages much higher than the target value of 15% are obtained. It should also be noted that within the regulatory group of elements, chromium (for which statistically significant PLS models could not be identified) was in all cases above the limit (Table S4 ).

Post-synthesis chemical treatment and thermal activation

The PLS results presented above clearly indicate the need for further treatments to improve the precautionary parameters foreseen by the European Standards. For this purpose, a sustainable chemical treatment strategy has been developed using the BioDea solution, a by-product of the gasification of wood waste biomass for energy production. This solution is characterized by a high content of acetic acid and phenolic acids with a distinctly acidic pH (see Table S9 for its characterization), thus being, in principle, suitable for the removal of inorganic species from the produced biochars.

In detail, B5, B6, B8-B12, and B9-B11 (i.e. the mixture of the biochars obtained with different production batches made under the same experimental conditions) were selected for the BioDea treatment as the materials produced with all the possible combinations of ST and WWB (Table  1 ) and providing the highest SSA values (258–370 m 2  g −1 ). These values are higher than those of biochars obtained elsewhere by co-pyrolysis of biological sludge with a number of vegetal feedstocks, such as bamboo sawdust (3–8 m 2  g −1 ), rice husk (4–11 m 2  g −1 ) (Zhang et al. 2020b ), and wheat straw (75–267 m 2  g −1 ) (Deng et al. 2017 ). B3-B10 was also chosen as the biochar replicates produced only from WWB and exhibiting the highest SSA values (552–580 m 2  g −1 ).

Figure  2 illustrates the effects of the BioDea treatment on the ash content, elements and PAHs release, and SSA of the aforementioned biochars. This treatment was able to strongly lower the ash content of all the materials investigated, even reducing it below the precautionary limit of 15% required by EN 12915–1. A similar result was obtained also for most of the leachable elements covered by this regulation, in accordance with the highly acidic and complexing characteristics of the BioDea solution, ascribable to the presence of high concentrations of acetic acid and (poly)phenolic substances (see Table S9 ). Pb and Ni represent exceptions as their leachable concentration before treatment was found to be below the quantification limit for all selected materials (i.e. < 0.5 µg L −1 ), while after washing with BioDea, the leachate showed quantifiable concentrations of both metals, albeit very low and within the limits of the aforementioned standard. In this regard, it should be noted that Ni and Pb were by far the most abundant elements found in BioDea among those included in EN 12915–1. Hence, it can be hypothesized that these metals were weakly adsorbed onto the materials during the washing procedure with BioDea and then released with the leaching test, which is performed with an aqueous solution containing significant concentrations of Na, Ca, and Mg ions (see section S.3.8 of the Supplementary material ). The treatment with BioDea and subsequent washing with deionized water did not produce appreciable variations in the release of PAHs from most biochars (Fig.  2 ), being B5 the sole exception. This biochar was the only material with leachable PAHs concentrations before treatment much higher than the limit of the European standard and showed a sharp reduction of such concentrations after treatment.

Mean values ( n  = 3) and standard deviation of ash, water extractable elements and polycyclic aromatic hydrocarbons (PAHs), and specific surface area (SSA) determined in biochars as such (dark grey bars) and treated with the BioDea solution (light grey bars). The dashed lines indicate the limits established by the UNI EN 12915–1. B3-B10, B8-B12, and B9-B11 refer to samples obtained by mixing equal aliquots of the two biochars

Overall, the results of the leaching test after the treatment with BioDea are interesting since they highlight the absence of environmental drawbacks in the use of this chemical treatment, notwithstanding its nature of “secondary product” obtained within the gasification of waste vegetal biomass for energy production.

Although the treatment with BioDea was able to remove significant amounts of inert constituents from the biochars, thus suggesting the possible increase of their porosity, no significant changes in SSA were observed in B5, B8-B12, and B9-B11, while there was even a significant decrease in the surface area of B6 and B3-B10. Thermal activation of B8-B12 and B9-B11 was then performed in an attempt to improve the SSA values. After this treatment, all the investigated leachable pollutants remained within the European standards, with main changes represented by the increase of Cr and the reduction of PAHs in the leachate of both treated materials (Fig.  3 ). However, the main result produced by the thermal activation was the higher SSA, which reached mean values of 360 and 460 m 2  g −1 for B8-B12 and B9-B11, respectively, corresponding to an increase of about 20%, compared to the not-activated materials. These values are remarkably interesting, considering that the biochars were prepared from a 30/70 dw/dw biological sludge-woody waste mixture and that the available SSA values for biochars derived from similar feedstocks are lower than those determined in this study (see Table S11 , Section S.8 of the Supplementary material ).

Mean values ( n  = 3) and standard deviation of ash, water extractable elements and polycyclic aromatic hydrocarbons (PAHs), and specific surface area (SSA) determined in biochars after treatment with the BioDea solution (dark grey bars) and successive thermal activation (light grey bars). The dashed lines indicate the limits established by the UNI EN 12915–1. B8-B12 and B9-B11 refer to samples obtained by mixing equal aliquots of the two biochars

B9-B11 was selected for further characterization due to its higher SSA values after thermal activation (Fig.  3 ). These characterizations included an in-depth physisorption analysis for investigating microporosity/mesoporosity of the materials and pH PZC (Table S12 of the Supplementary material ), as well as thermogravimetric analysis (TGA, Fig.  4 ), X-ray diffraction (XRD, Fig.  5 A–D), and scanning electron microscopy (SEM, Fig.  6 A–H), which were performed on (i) the original material, as well as (ii) the one washed with BioDea (B9-B11 (BD) ) and (iii) the one washed and thermally activated (B9-B11 (BD−TA) ).

Thermogravimetric analysis of the biochar B9-B11 (wide dashed line), after washing with BioDea (B9-B11 (BD) , dashed line), and successive thermal activation (B9-B11 (BD−TA) ), solid line), in comparison with a commercial activated carbon (AC, dotted line). The analysis was performed from 40 to 460 °C at 10 °C min −1 under nitrogen flow of 100 mL min −1

X-ray diffraction analysis of A activated carbon, B untreated biochar B9-B11, C B9-B11 after washing with BioDea (B9-B11 (BD) ), and D successive thermal activation (B9-B11 (BD−TA) ). Calcite and hydroxyapatite phases are labelled with red and green tags, respectively

SEM images of B9-B11 ( A , B ), B9-B11 (BD) ( C , D ), B9-B11 (BD−TA) ( E , F ), and AC ( G , H ) taken at different magnifications. Dotted boxes identify the regions that underwent magnification

The sum of the t-plot microporous and BJH mesoporous areas was only slightly lower than the BET total SSA, thus suggesting a low contribution of macropores to the total surface area (Table S12 ). Although the three materials were characterized by a prevalent microporosity, the treatments performed on the biochar influenced the pore size distribution. In fact, the washing with BioDea strongly increased the microporosity, while decreasing mesoporosity. This result may be due to the ability of the washing solution to remove small size compounds that filled micropores, while higher size organic compounds present in the BioDea (e.g. polyphenolic compounds) could partially saturate the mesopores. Thermal activation showed an opposite effect, since a decrease in microporosity and an increase in mesoporosity were observed, consistently with a swelling-like temperature-dependent phenomenon and the thermal degradation of the pore-filling organic compounds.

The TGA highlighted an excellent resistance of both B9-B11 and B9-B11 (BD) . In fact, the chars showed a very small weight loss (i.e. about 7%) in the investigated temperature range (i.e. up to about 500 °C). The thermal activation significantly increased this resistance, leading to a material behaving very similar to the AC in the investigated temperature range, being their weight losses approximately of 4.5% and 3.5%, respectively. It should also be noted that these results support the reliability of the surface area data, which were obtained after degassing at 200 °C.

XRD pattern for the AC (Fig.  5 A) showed broad asymmetric peaks corresponding to 2θ≈25° and 45°, typically found in commercially available virgin activated carbons from vegetal feedstocks (Cheng et al. 2020 ; Wu et al. 2017 ) and attributable to the presence of amorphous carbon partially composed of sheets of randomly oriented aromatic carbon (Suganuma et al. 2008 ). In contrast, diffractograms of untreated biochar (Fig.  5 B), after washing (Fig.  5 C), and subsequent thermal activation (Fig.  5 D) show completely different profiles from that of activated carbon, in accordance with the completely different nature of the feedstocks used. In detail, the XRD spectra of the three biochars show narrow peaks of increasing intensity from untreated biochar to BioDea-washed biochar and finally to thermally activated biochar, highlighting the increasing formation of crystalline phases along the treatments. These crystalline phases mainly consist of calcite and hydroxyapatite, as demonstrated by the comparison with XRD reference libraries. Although the presence of aromatic moieties in this type of material is a constant (Fan et al. 2023 ), no clear evidence of the occurrence of graphite-like sheets has been observed.

SEM images (Fig.  6 A–H) allowed making some considerations about the morphology of the investigated materials. As a general consideration, all biochars (Fig.  6 A–F) exhibited a wider particle size distribution than AC (Fig.  6 G–H). In fact, the latter consisted in particles dimensionally more homogeneous, most of them < 5 µm. This finding reflects the different characteristics of the feedstocks used for the preparation of the two kinds of materials. Particles of different shapes can be observed in all biochars. In particular, rather large particles with an elongated shape, smaller particles without a defined shape, and honeycomb-like shapes were highlighted, the latter after washing with BioDea. The SEM–EDX analysis allowed performing a semi-quantitative evaluation of the elemental composition of the particles; a representative example showing the results obtained for some data acquisitions performed on the B9-B11 (BD) is reported in Fig.  7 . Most particles consisted almost completely in carbon (see panels 1–2), while others (see panels 3–4) contained also significant amounts of other elements such as P, S, Ca, Mg, Fe, and Al, thus highlighting the composite nature of the materials. This heterogeneous composition is in accordance with the heterogeneity of the mixed feedstocks and the recycled solution used for preparing and washing the material, respectively. More in detail, the presence of particles with a high Fe and Al content can be explained by the use of ferric chloride and aluminium polychloride during the sedimentation and clariflocculation stages of the wastewater treatment.

Representative SEM–EDX results obtained on the B9-B11 ( . BD)

Evaluation of adsorption capacity in ultrapure water

Sorption capacity of B9-B11 (BD) and B9-B11 (BD−TA) was evaluated towards MB and DY by kinetic and isotherm analyses in ultrapure water, using AC as reference material.

Kinetic test

As illustrated in Figure S8 of the Supplementary Material , appreciable removals were determined with B9-B11 (BD) for MB and especially with B9-B11 (BD−TA) for both dyeing agents, while no significant removal was observed for DY using the B9-B11 (BD) (data not reported), evidencing its poor adsorption capacity for this molecule. Considering that AC was used in kinetic tests in quantities an order of magnitude lower than biochar (see section S.6.1), its removal capacity was higher than that of biochar (Fig. S8 ). The data clearly showed that the highest and most stable uptake of dyeing agents was obtained with a contact time ranging from 60 to 120 min, while the increase to 180 min offered no improvement in the removal. These results highlighted a quite fast adsorption kinetic for all biochars that is encouraging for their use in real systems. According to the results of the adsorption kinetic studies, a contact time of 120 min was selected for the isotherm tests.

Adsorption isotherms

The interpretation of the experimental results of adsorption tests was attempted with both Langmuir and Freundlich models. However, the linearized Freundlich equation provided models with low statistical significance (low R 2 values and P  > 0.05, data not shown). Conversely, Langmuir equation generally produced significant models and was therefore used for data interpretation (see Table  2 ). Based on Langmuir Q m data determined in ultrapure water, it was clear that the thermal activation significantly increased the sorption capacity of the biochar, leading for MB to a Q m value about 8 times higher (62 vs. 7.6 mg g −1 ) and making detectable the maximum adsorption for DY (5.2 mg g −1 ). Based on the surface properties of the materials (i.e. SSA, porosity distribution, and surface charge), it is possible to propose mechanistic interpretations of the adsorption data obtained. The higher sorption of B9-B11 (BD−TA) is consistent with the higher SSA and mesoporosity of this material, both playing a relevant role in the adsorption of organic molecules and especially compounds with diameter larger than 2 nm, as in the case of DY. Interestingly, the thermally activated biochar provided Q m values only 2.5 times lower than the one obtained with AC used here as a comparison (62 vs. 153 mg g −1 and 5.2 vs. 12 mg g −1 for MB and DY, respectively). These results agree with the higher SSA value found for AC (785 m 2  g −1 ) compared to B9-B11 (BD−TA) (460 m 2  g −1 ) (Table S12 ). MB exhibited higher Q m values than DY both with B9-B11 (BD−TA) and AC, probably owing to the significantly different size of the two molecules (maximum diameter of about 1.4 and 2.6 nm for MB and DY, respectively), which determines a much lower surface area available for DY adsorption, rather than for MB removal. In any case, π-π interactions between aromatic moieties of the material and the dyes play a role in their adsorption. Conversely, our findings seem not to be related to a role of electrostatic attractions/repulsions between adsorbate and adsorbent. In fact, under the pH conditions of ultrapure water added with dyeing agents (pH = 5.9), B9-B11 (BD−TA) has a positive net surface charge and should therefore adsorb better DY than MB if the electrostatic sorption mechanism played an important role in governing dyes removal. A less important role of pure electrostatic interactions in the removal of dyeing agents by biochars was also observed by other researchers (Spagnoli et al. 2017 ; Sumalinog et al. 2018 ), who proposed different non-electrostatic interactions (i.e. dipole–dipole and π-π), and pore dimension as major driving forces for explaining sorption phenomena.

It is interesting to compare the best Q m value determined here with those reported elsewhere for biochars obtained from mixtures of WWBs and BSs in proportions similar to that used for the preparation of B9-B11 (Table S11 ). Removal of MB has been previously investigated by some researchers (Chen et al. 2019 ; Cheng et al. 2013 ; Dai et al. 2022a , 2022b ; Fan et al. 2016 ; Kenchannavar and Surenjan 2022 ; Xiang et al. 2023 ), while no previous study has been performed on DY. Our best result (62 mg g −1 ), obtained after washing and thermal activation of the B9-B11, is included in the wide range of literature Q m data (8.1–115 mg g −1 ), but it ranks among the best literature values, being much higher than their mean and median (38 and 23 mg g −1 ).

Evaluation of adsorption capacity in real wastewater

The results obtained for B9-B11 (BD−TA) in ultrapure water are encouraging to evaluate the potential of this material for the removal of dyes in real wastewater. Hence, adsorption isotherm and breakthrough column tests were conducted on the effluent from the clariflocculation of the same WWTP from which the BS was collected for biochar production.

Table 2 shows the results of modelling the experimental adsorption data in effluent wastewater, using the Langmuir equation. In this complex matrix, the removal of the two dyes by biochar and AC showed differences from what was observed in ultrapure water, thus highlighting the importance of evaluating the removal performances in real wastewater. However, the lower sorption efficiency of B9-B11 (BD) compared to B9-B11 (BD−TA) was confirmed, being Q m values measurables only for the thermally activated material. Moreover, in agreement with findings in ultrapure water, AC showed also in real wastewater an adsorption capacity 2–9 times higher than the thermally activated biochar.

Breakthrough column tests

To evaluate the sorption capacity of B9-B11 (BD−TA) under experimental conditions closer to real applications of wastewater refining, breakthrough column tests were performed (see section S.6.1 for full details). A representative example of the trend of MB concentrations in the column effluent during the experiment is shown in Figure S9 of the Supplementary Material . A quantitative removal of MB was achieved for the first 8 L of filtered wastewater, which corresponds to the removal of about 413 mg of MB, i.e. about 11.8 mg/g of biochar. Then, MB effluent concentration starts to grow until it reaches the initial concentration of about 52 mg L −1 after the filtration of an additional 10 L of wastewater. Overall, the total removal of MB in the columns was about 21 mg/g of biochar, which is in very good agreement with the Q m value determined by isotherm tests (28 mg g −1 , Table  2 ).

Conclusions

This study provided in-depth knowledge of the physicochemical properties of biochar produced by thermal conversion of sludge from predominantly industrial wastewater input, a topic poorly described in the literature, making interesting considerations about the biochar characteristics in relation to the production conditions, including type and percentage of sludge used as feedstock.

Post-synthesis chemical treatment of biochars was allowed for obtaining materials complying with EN 12915–1, even in the presence of sludge from the treatment of mixed industrial-municipal wastewater, with a percentage in the feedstock as high as 30%, thus achieving the “end-of-waste” condition for this sludge. In this regard, the use of a low-cost and sustainable “secondary product”, obtained within the gasification of waste vegetal biomass for energy production, should be considered a significant added value of the proposed process.

The subsequent thermal activation, carried out on biochar containing 30% of sludge, provided an increase in surface area up to 460 m 2  g −1 , without compromising the compliance with the aforementioned standard, thus allowing to obtain promising materials for the adsorption of organic micropollutants. This biochar was able to provide direct yellow 50 and methylene blue adsorption capacities, only 2–9 times lower than those achieved by a commercial activated carbon. These removals were obtained in real wastewater sampled from the WWTP from which the sludge used as feedstock derives, thus suggesting a possible closure of the “sludge cycle” inside the facility. As reported elsewhere (Castiglioni et al. 2021 , 2022 ; Del Bubba et al. 2020 ), it should be stressed the importance of evaluating the removal capacity of non-conventional materials in comparison with reference ones (such as in this case activated carbons), since the reliability of the data obtained is enhanced.

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Acknowledgements

The authors are grateful to Romana Maceri Centro Italia S.r.l. and Bio-Esperia S.r.l. for supplying sawdust and BioDea solution, respectively.

Open access funding provided by Università degli Studi di Firenze within the CRUI-CARE Agreement. This work was supported by the Ministero della Transizione Ecologica through the “BIOINNOVA” project (CUP B96C18001210001). Michelangelo Fichera gratefully acknowledges MUR and EU-FSE for the financial support of the PhD fellowship PON Research and Innovation 2014–2020 (D.M 1061/2021) XXXVII Cycle in Chemical Sciences.

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Zaineb Bakari, Michelangelo Fichera, Ayoub El Ghadraoui, Lapo Renai, Walter Giurlani & Massimo Del Bubba

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Zaineb Bakari

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Daniela Santianni

Gestione Impianti di Depurazione Acque (G.I.D.A.) S.P.A, Via di Baciacavallo 36, 59100, Prato, Italy

Donatella Fibbi

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Contributions

Biochar production, chemical treatment, thermal activation, analysis of ash, leachable metals, pH PZC , physisorption analyses, TGA, XRD, sorption, and column experiments were performed by Zaineb Bakari, Michelangelo Fichera, and Ayoub El Ghadraoui. Chemometrics and computational analyses were performed by Lapo Renai. SEM and SEM–EDX analyses were performed by Walter Giurlani. Massimo Del Bubba, Maria Concetta Bruzzoniti, Donatella Fibbi, and Daniela Santianni contributed to the study conception and design. The first draft of the manuscript was written by Massimo Del Bubba and Michelangelo Fichera, and all authors commented on previous versions of the manuscript.

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Correspondence to Massimo Del Bubba .

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Bakari, Z., Fichera, M., El Ghadraoui, A. et al. Biochar from co-pyrolysis of biological sludge and woody waste followed by chemical and thermal activation: end-of-waste procedure for sludge management and biochar sorption efficiency for anionic and cationic dyes. Environ Sci Pollut Res (2024). https://doi.org/10.1007/s11356-024-33577-3

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Received : 16 January 2024

Accepted : 30 April 2024

Published : 09 May 2024

DOI : https://doi.org/10.1007/s11356-024-33577-3

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Global chemical plastics recycling and dissolution industry research 2024-2040 with profiles of 160+ technology developers, equipment manufacturers, chemical producers, and waste management companies.

Dublin, May 09, 2024 (GLOBE NEWSWIRE) -- The "The Global Market for Chemical Recycling and Dissolution of Plastics 2024-2040" report has been added to ResearchAndMarkets.com's offering.

The report begins by examining the global production and use of plastics, highlighting the importance of this material in modern society, as well as the issues associated with its widespread adoption. It delves into the rise of bio-based and biodegradable plastics, as well as the growing problem of plastic pollution and the policy and regulatory responses shaping the industry.

The global plastics industry is facing a growing challenge - the need to address the environmental impact of plastic waste. As traditional waste management methods struggle to keep pace, advanced chemical recycling and dissolution technologies have emerged as a crucial solution to transform the industry towards a more sustainable, circular model. This comprehensive market report provides an in-depth analysis of the rapidly evolving landscape of chemical recycling and dissolution, offering stakeholders a roadmap to navigate this transformative shift.

At the heart of this report lies a detailed analysis of the advanced chemical recycling market, exploring the key drivers and trends that are propelling its growth. The report tracks the industry's dynamic developments, funding, and capacity expansions from 2020 to 2024, painting a comprehensive picture of the competitive landscape.

A critical comparative analysis of mechanical and chemical recycling is presented, underscoring the advantages and limitations of each approach. The report then provides an in-depth forecast of global polymer demand segmented by recycling technology, polymer type, and geographic region, offering stakeholders valuable insights to guide their strategic decision-making.

The report delves into the various advanced recycling technologies, including pyrolysis, gasification, dissolution, and depolymerization, providing a thorough examination of their technical attributes, applications, market forecasts, and leading industry players. It also explores emerging trends, such as the recycling of thermoset materials and the chemical recycling of textiles, highlighting the industry's continuous evolution.

For each technology, the report provides a technical overview, market forecasts, SWOT analysis, and the leading industry players and their current and planned capacities. Additionally, the report explores emerging advanced recycling approaches, including hydrothermal cracking, microwave-assisted pyrolysis, plasma technologies, and the recycling of thermoset materials and carbon fibers, highlighting the continued innovation in this dynamic market.

The report projects the global demand for chemically recycled plastics to grow significantly, outpacing the growth of mechanically recycled plastics in key applications. This trajectory is driven by the increasing adoption of advanced recycling technologies, the need for higher-quality recycled content, and the rising demand for sustainable materials across diverse industries.

The global demand for chemically recycled plastics is analyzed across key regions, including Europe, North America, South America, Asia, Oceania, and Africa. The report provides detailed forecasts of polymer demand by recycling technology for each region, equipping stakeholders with a comprehensive understanding of the geographic dynamics shaping the industry.

The report examines the life cycle assessments of advanced chemical recycling processes, comparing the environmental impacts and resource efficiency with traditional virgin plastic production and mechanical recycling. This analysis empowers stakeholders to make informed decisions and communicate the sustainability benefits of their products. The report also addresses the key challenges facing the advanced chemical recycling market, including technological limitations, feedstock availability, regulatory hurdles, and economic barriers, providing a balanced perspective on the industry's growth trajectory.

The report concludes with an extensive company profiling section, featuring over 160 leading players in the chemical recycling and dissolution market. This comprehensive industry landscape covers the technology developers, equipment manufacturers, chemical producers, and waste management companies driving the transformation of the plastics value chain. Each company profile provides detailed information on the organization's technology, capacity, strategic initiatives, and market positioning, equipping stakeholders with the necessary insights to identify potential partners, competitors, and investment opportunities.

Companies profiled include

Extracthive

Fych Technologies

Hyundai Chemical Ioniqa

Mura Technology

revalyu Resources GmbH

Plastogaz SA

Plastic Energy

Polystyvert

RePEaT Co., Ltd

Key Topics Covered:

1 CLASSIFICATION OF RECYCLING TECHNOLOGIES

2 RESEARCH METHODOLOGY

3 INTRODUCTION 3.1 Global production of plastics 3.2 The importance of plastic 3.3 Issues with plastics use 3.4 Bio-based or renewable plastics 3.4.1 Drop-in bio-based plastics 3.4.2 Novel bio-based plastics 3.5 Biodegradable and compostable plastics 3.5.1 Biodegradability 3.5.2 Compostability 3.6 Plastic pollution 3.7 Policy and regulations 3.8 The circular economy 3.9 Plastic recycling 3.9.1 Mechanical recycling 3.9.2 Advanced recycling (molecular recycling, chemical recycling) 3.10 Life cycle assessment

4 CHEMICAL RECYCLING MARKET 4.1 Market drivers and trends 4.2 Industry news, funding and developments 2020-2024 4.3 Capacities 4.4 Mechanical vs. Chemical Recycling 4.5 Global polymer demand 2022-2040, segmented by recycling technology 4.5.1 PE 4.5.2 PP 4.5.3 PET 4.5.4 PS 4.5.5 Nylon 4.5.6 Others 4.6 Mechanical vs chemical recycled packaging consumption by material, 2024-2040 4.6.1 PET 4.6.2 HDPE 4.6.3 LDPE 4.6.4 PP 4.6.5 PS 4.7 Global polymer demand 2022-2040, segmented by recycling technology, by region 4.8 Chemically recycled plastic products 4.9 Market map 4.10 Value chain 4.11 Life Cycle Assessments (LCA) of advanced plastics recycling processes 4.11.1 PE 4.11.2 PP 4.11.3 PET 4.12 Recycled plastic yield and cost 4.12.1 Plastic yield of each chemical recycling technologies 4.12.2 Prices 4.13 Market challenges

5 CHEMICAL RECYCLING TECHNOLOGIES 5.1 Applications 5.2 Pyrolysis 5.2.1 Feedstocks 5.2.2 Non-catalytic 5.2.3 Catalytic 5.2.4 SWOT analysis 5.2.5 Market forecast by polymer type 5.2.6 Companies and capacities 5.3 Gasification 5.3.2 Market forecast by polymer type 5.3.3 SWOT analysis 5.3.4 Companies and capacities (current and planned) 5.4 Dissolution 5.5 Depolymerisation 5.5.1 Hydrolysis 5.5.2 Enzymolysis 5.5.3 Methanolysis 5.5.4 Glycolysis 5.5.5 Aminolysis 5.5.6 Market forecast by polymer type 5.5.7 Companies and capacities (current and planned) 5.6 Other advanced chemical recycling technologies 5.6.1 Hydrothermal cracking 5.6.2 Pyrolysis with in-line reforming 5.6.3 Microwave-assisted pyrolysis 5.6.4 Plasma pyrolysis 5.6.5 Plasma gasification 5.6.6 Supercritical fluids 5.6.7 Carbon fiber recycling 5.6.8 PHA chemical recycling 5.7 Advanced recycling of thermoset materials 5.7.1 Thermal recycling 5.7.2 Solvolysis 5.7.3 Catalyzed Glycolysis 5.7.4 Alcoholysis and Hydrolysis 5.7.5 Ionic liquids 5.7.6 Supercritical fluids 5.7.7 Plasma 5.7.8 Companies 5.8 Chemical recycling of textiles 5.8.1 Overview 5.8.2 Commercial activity

6 COMPANY PROFILES (169 Included)

For more information about this report visit https://www.researchandmarkets.com/r/duu89o

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