Potential of Bauhinia Racemosa Sawdust for Chromium (VI) Removal: Adsorption Optimization and Mechanistic Insights

Potential of Bauhinia Racemosa Sawdust for Chromium (VI) Removal: Adsorption Optimization and Mechanistic Insights | 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 Research Article Potential of Bauhinia Racemosa Sawdust for Chromium (VI) Removal: Adsorption Optimization and Mechanistic Insights Prajakta Magdum, Nilisha Itankar This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7117653/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Dec, 2025 Read the published version in Discover Sustainability → Version 1 posted 12 You are reading this latest preprint version Abstract The purpose of the present study was to assess the effectiveness of Bauhinia racemosa sawdust powder (BRSP) for its potential use as a low-cost ligno-cellulosic adsorbent for the removal of hexavalent chromium [Cr(VI)] from aqueous solution. Adsoprtion study based batch experiments were conducted to study the various factors affecting adsorption, such as Cr(VI) concentration, initial pH, biosorbent particle size, contact time, and solution volume. The biosorbent was also characterized by FTIR, BET analysis, and SEM-EDX. The surface area, proximate analysis, Boehm titration, and point of zero charge estimation (pHPZC) were measured to determine the surface characteristics and functional group interactions. Maximum Cr(VI) removal was 99.78% and maximum Cr(VI) adsorption was 106.86 mg/g under optimal conditions (pH 4.0, dose of 0.4 g of grains in 100 mL of solution for a particle size of 75 µm with 100 mg/L concentration and a contact time of one h). The Langmuir isotherm model effectively fits the adsorption equilibrium data, indicating monolayer adsorption. Nevertheless, kinetic runs based on the pseudo-second-order model indicated that chemisorption was the predominant process. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) suggested that the process was spontaneous and endothermic. These results indicated that BRSP is a promising sustainable biosorbent for removing Cr(VI) from polluted water, offering a green strategy for resource recycling and effluent treatment in diverse industries. The driving forces are van der Waals interaction, π-π stacking, hydrophobic, and electrostatic interactions. Adsorption hexavalent chromium isotherm models BET SEM-EDX Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 11 Dec, 2025 Read the published version in Discover Sustainability → Version 1 posted Editorial decision: Revision requested 18 Aug, 2025 Reviews received at journal 12 Aug, 2025 Reviews received at journal 11 Aug, 2025 Reviews received at journal 09 Aug, 2025 Reviewers agreed at journal 31 Jul, 2025 Reviewers agreed at journal 31 Jul, 2025 Reviewers agreed at journal 30 Jul, 2025 Reviewers invited by journal 30 Jul, 2025 Editor invited by journal 29 Jul, 2025 Editor assigned by journal 26 Jul, 2025 Submission checks completed at journal 26 Jul, 2025 First submitted to journal 14 Jul, 2025 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. 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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-7117653","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":493702492,"identity":"86037627-1ed8-480d-a883-43741d0679b0","order_by":0,"name":"Prajakta Magdum","email":"","orcid":"","institution":"Symbiosis Institute of Technology, Symbiosis International (Deemed University)","correspondingAuthor":false,"prefix":"","firstName":"Prajakta","middleName":"","lastName":"Magdum","suffix":""},{"id":493702493,"identity":"7260f982-b4cb-44f5-a700-129ba02d39ea","order_by":1,"name":"Nilisha Itankar","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9ElEQVRIiWNgGAWjYDACZuaGA4wNDDz8DEASCgzACLcWRogWyQbGxgbitIAMB5lvcABhDV71DObsjI0Hf+6wkzE+f7j9cWHbHTkG9uZtEgwFd3BqsWxmbDjMeyaZx+xGYmPzzLZnxgw8x8okGAye4dRicBiohbGNGaiFsbGZt+1wYoNEjhlQy2G8Wg7+bKvnMe4/CNZS3yD/hrCWA0CVPAYMiWAtCQwSPIS1HOZtO84jAfTL7BnnDhu28aQVWyTg03L+8OGPP9uq7fn7jz/4XFB2WJ6f/fDGGx/+4NaCAphBBBuISCBOA1TLKBgFo2AUjAJ0AAB/fFb7SdQUVQAAAABJRU5ErkJggg==","orcid":"","institution":"Symbiosis Institute of Technology, Symbiosis International (Deemed University)","correspondingAuthor":true,"prefix":"","firstName":"Nilisha","middleName":"","lastName":"Itankar","suffix":""}],"badges":[],"createdAt":"2025-07-14 06:38:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7117653/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7117653/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s43621-025-02378-0","type":"published","date":"2025-12-11T15:56:59+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":98243490,"identity":"a87b2d42-0537-4104-a62c-9502369e4072","added_by":"auto","created_at":"2025-12-15 16:06:38","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1284427,"visible":true,"origin":"","legend":"","description":"","filename":"PotentialofBRSPforCr21.7.2025.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7117653/v1_covered_0a1ac4cc-fbe8-45e1-be90-d6d4384f10c7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Potential of Bauhinia Racemosa Sawdust for Chromium (VI) Removal: Adsorption Optimization and Mechanistic Insights","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-sustainability","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"disu","sideBox":"Learn more about [Discover Sustainability](https://www.springer.com/43621)","snPcode":"","submissionUrl":"","title":"Discover Sustainability","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Adsorption, hexavalent chromium, isotherm models, BET, SEM-EDX","lastPublishedDoi":"10.21203/rs.3.rs-7117653/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7117653/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe purpose of the present study was to assess the effectiveness of Bauhinia racemosa sawdust powder (BRSP) for its potential use as a low-cost ligno-cellulosic adsorbent for the removal of hexavalent chromium [Cr(VI)] from aqueous solution. Adsoprtion study based batch experiments were conducted to study the various factors affecting adsorption, such as Cr(VI) concentration, initial pH, biosorbent particle size, contact time, and solution volume. The biosorbent was also characterized by FTIR, BET analysis, and SEM-EDX. The surface area, proximate analysis, Boehm titration, and point of zero charge estimation (pHPZC) were measured to determine the surface characteristics and functional group interactions. Maximum Cr(VI) removal was 99.78% and maximum Cr(VI) adsorption was 106.86 mg/g under optimal conditions (pH 4.0, dose of 0.4 g of grains in 100 mL of solution for a particle size of 75 µm with 100 mg/L concentration and a contact time of one h).\u003c/p\u003e\n\u003cp\u003eThe Langmuir isotherm model effectively fits the adsorption equilibrium data, indicating monolayer adsorption. Nevertheless, kinetic runs based on the pseudo-second-order model indicated that chemisorption was the predominant process. 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