Synergistic adsorption of anionic and cationic dyes using commingled food waste biochar from microwave-assisted pyrolysis

Synergistic adsorption of anionic and cationic dyes using commingled food waste biochar from microwave-assisted pyrolysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Synergistic adsorption of anionic and cationic dyes using commingled food waste biochar from microwave-assisted pyrolysis Venkat Srinadh Rejeti, Remya Neelancherry This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8798626/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Biochar is a versatile carbon-rich material with multifaceted applications in environmental remediation, sustainable agriculture, waste valorization, carbon sequestration, and energy systems, and is particularly valued as a highly effective and tunable adsorbent for the removal of diverse contaminants—including dyes, heavy metals, nutrients, pharmaceuticals, and emerging pollutants—from water and wastewater. The current study employed commingled food waste biochar (CFWB), along with its acid-modified (A-CFWB) and alkali-modified (Al-CFWB) forms, produced from food waste and LDPE through microwave-assisted pyrolysis to remove Congo red (CR) and Methylene blue (MB) from single and binary dye systems. CR and MB removal from single dye system were in the order A-CFWB (79.5%) > CFWB (75.4 %) > Al-CFWB (63 %) and Al-CFWB (83.7%) > CFWB (70.1%) > A-CFWB (59.5%) respectively. Al-CFWB displayed superior CR (71.2%) and MB (96.7%) removal from binary dye system compared to A-CFWB (63.3% and 51.1%) and pristine CFWB (59.7% and 61.9%), with an overall maximum adsorption capacity of 33.6 mg/g. Better CR removal from binary dye system (71.2%) was observed due to complex formation between oppositely charged CR and MB, compared to single dye system (63%). Monolayer CR and MB adsorption on Al-CFWB was represented by the Langmuir isotherm. Chemisorption was the rate-limiting mechanism for dye removal from single and binary dye systems, with a strong co-relation with pseudo-second order kinetic model. Al-CFWB was reusable, removing ~86% of MB from binary dye system after five reutilization cycles. The oxygen-containing functional groups and distinct porous structure of Al-CFWB (5.95 µm average pore size) facilitated surface accessibility for dye adsorption. These results indicated that Al-CFWB is an effective adsorbent for the removal of CR and MB from binary dye system. Moreover, this research emphasized on the conversion of abundantly available commingled food waste into CFWB and its application as an effective adsorbent for multi-dye removal from wastewaters which serves the dual purpose of efficacious waste valorization and pollution control for sustainable development and environmental safety contemplating to UN Sustainable Development Goals. Physical sciences/Chemistry Earth and environmental sciences/Environmental sciences Adsorption isotherm Adsorption kinetics Binary dye system Commingled food waste biochar Synergistic dye adsorption Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8798626","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":593885389,"identity":"258dcab5-c889-4742-ad4a-d267da289d95","order_by":0,"name":"Venkat Srinadh Rejeti","email":"","orcid":"","institution":"Indian Institute of Technology Bhubaneswar","correspondingAuthor":false,"prefix":"","firstName":"Venkat","middleName":"Srinadh","lastName":"Rejeti","suffix":""},{"id":593885390,"identity":"9088a2ea-03de-4ce4-9359-4d90b22930e6","order_by":1,"name":"Remya Neelancherry","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAx0lEQVRIiWNgGAWjYNCCCgkeBiACAzbitJyR4OEhTQtjGwMDXAtBYN7enSbxc56FjL107+EPDDV2DHzSDfi1yJw5u02ydxvQYTLn0iQYjiUzsMkcwK9FQiJ3mwQvSItEjhnQIwcY2CQSCGiRf7tN8u8csBbjDwz/iNECtEKatwGsxUCCsY0YLTy5m61ljgG13AH6JbEvmYewFvazG2++qamzZ58NDLEP3+zk5GcQ0AIELBJwJlAxUbHD/IEYVaNgFIyCUTCCAQCkLjT6aORrvwAAAABJRU5ErkJggg==","orcid":"","institution":"Indian Institute of Technology Bhubaneswar","correspondingAuthor":true,"prefix":"","firstName":"Remya","middleName":"","lastName":"Neelancherry","suffix":""}],"badges":[],"createdAt":"2026-02-05 15:08:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8798626/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8798626/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[],"financialInterests":"No competing interests reported.","formattedTitle":"Synergistic adsorption of anionic and cationic dyes using commingled food waste biochar from microwave-assisted pyrolysis","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Adsorption isotherm, Adsorption kinetics, Binary dye system, Commingled food waste biochar, Synergistic dye adsorption","lastPublishedDoi":"10.21203/rs.3.rs-8798626/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8798626/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBiochar is a versatile carbon-rich material with multifaceted applications in environmental remediation, sustainable agriculture, waste valorization, carbon sequestration, and energy systems, and is particularly valued as a highly effective and tunable adsorbent for the removal of diverse contaminants—including dyes, heavy metals, nutrients, pharmaceuticals, and emerging pollutants—from water and wastewater. The current study employed commingled food waste biochar (CFWB), along with its acid-modified (A-CFWB) and alkali-modified (Al-CFWB) forms, produced from food waste and LDPE through microwave-assisted pyrolysis to remove Congo red (CR) and Methylene blue (MB) from single and binary dye systems. CR and MB removal from single dye system were in the order A-CFWB (79.5%) \u0026gt; CFWB (75.4 %) \u0026gt; Al-CFWB (63 %) and Al-CFWB (83.7%) \u0026gt; CFWB (70.1%) \u0026gt; A-CFWB (59.5%) respectively. Al-CFWB displayed superior CR (71.2%) and MB (96.7%) removal from binary dye system compared to A-CFWB (63.3% and 51.1%) and pristine CFWB (59.7% and 61.9%), with an overall maximum adsorption capacity of 33.6 mg/g. Better CR removal from binary dye system (71.2%) was observed due to complex formation between oppositely charged CR and MB, compared to single dye system (63%). \u0026nbsp;Monolayer CR and MB adsorption on Al-CFWB was represented by the Langmuir isotherm. 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