Adsorptive removal of lead (Pb2+) ions using carbon–based magnetic nanocomposite

Adsorptive removal of lead (Pb2+) ions using carbon–based magnetic nanocomposite | 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 Adsorptive removal of lead (Pb 2+ ) ions using carbon–based magnetic nanocomposite Saaed Zeinali Heris, Faezeh Dehghan, Seyed Borhan Mousavi, Mohammad Ghorbanpour This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9314991/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 Lead (Pb 2+ ) contamination in aquatic environments poses a serious risk to human health and ecosystems, necessitating the development of efficient, sustainable, and regenerable adsorbent materials. In this study, a carbon-based magnetic nanocomposite (AC/MnFe 2 O 4 ) derived from orange peel waste was synthesized and systematically evaluated for Pb 2+ removal from aqueous solutions. The structural, morphological, elemental, and magnetic properties of the synthesized materials were characterized using SEM, EDX, XRD, and VSM, confirming successful immobilization of MnFe 2 O 4 nanoparticles onto the porous activated carbon matrix and sufficient magnetic separability. The effects of key operational parameters, including solution pH (2–10), initial Pb 2+ concentration, adsorbent dosage, temperature (25–60°C), and contact time, were systematically investigated. Adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Equilibrium data were evaluated using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) isotherm models. The Langmuir model exhibited excellent agreement with experimental data, yielding a high maximum adsorption capacity of 129.87 mg/g and a favorable separation factor (R L =0.023). The low mean adsorption energy obtained from the D–R model (E = 3.79 kJ/mol) suggests that Pb 2+ adsorption is predominantly governed by physisorption mechanisms. Thermodynamic analysis revealed negative Gibbs free energy values (ΔG°=−6.72 to − 0.45 kJ/mol) at lower temperatures, confirming the spontaneous nature of Pb 2+ adsorption, while the negative enthalpy change (ΔH°=−60.75 kJ/mol) indicates an exothermic process. Reusability studies demonstrated that the AC/MnFe 2 O 4 nanocomposite retained over 66% of its initial adsorption efficiency after nine adsorption–desorption cycles. The combination of high adsorption capacity, favorable kinetics, magnetic recoverability, and good regeneration performance highlights the AC/MnFe 2 O 4 nanocomposite as a promising and sustainable adsorbent for Pb 2+ remediation in water treatment applications. Chemical Engineering Environmental Chemistry Materials Chemistry Lead removal Activated carbon MnFe2O4 nanocomposite Adsorption Water treatment Full Text Additional Declarations The authors declare no competing interests. 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-9314991","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":617266504,"identity":"43c4a309-fea5-456e-a234-a545aaae2860","order_by":0,"name":"Saaed Zeinali 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16:45:31","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9314991/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9314991/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106402636,"identity":"9fc12898-4b9e-4939-9bdb-10fc938363e3","added_by":"auto","created_at":"2026-04-08 09:12:29","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":903113,"visible":true,"origin":"","legend":"","description":"","filename":"FaezehDehghanRS.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9314991/v1_covered_2777e00f-8da2-4872-981c-39f537509fb4.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eAdsorptive removal of lead (Pb\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e2+\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e) ions using carbon–based magnetic nanocomposite\u003c/strong\u003e\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Texas A\u0026M University","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":"Lead removal, Activated carbon, MnFe2O4 nanocomposite, Adsorption, Water treatment","lastPublishedDoi":"10.21203/rs.3.rs-9314991/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9314991/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eLead (Pb\u003csup\u003e2+\u003c/sup\u003e) contamination in aquatic environments poses a serious risk to human health and ecosystems, necessitating the development of efficient, sustainable, and regenerable adsorbent materials. In this study, a carbon-based magnetic nanocomposite (AC/MnFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) derived from orange peel waste was synthesized and systematically evaluated for Pb\u003csup\u003e2+\u003c/sup\u003e removal from aqueous solutions. The structural, morphological, elemental, and magnetic properties of the synthesized materials were characterized using SEM, EDX, XRD, and VSM, confirming successful immobilization of MnFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles onto the porous activated carbon matrix and sufficient magnetic separability. The effects of key operational parameters, including solution pH (2\u0026ndash;10), initial Pb\u003csup\u003e2+\u003c/sup\u003e concentration, adsorbent dosage, temperature (25\u0026ndash;60\u0026deg;C), and contact time, were systematically investigated. Adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Equilibrium data were evaluated using Langmuir, Freundlich, Temkin, and Dubinin\u0026ndash;Radushkevich (D\u0026ndash;R) isotherm models. The Langmuir model exhibited excellent agreement with experimental data, yielding a high maximum adsorption capacity of 129.87 mg/g and a favorable separation factor (R\u003csub\u003eL\u003c/sub\u003e=0.023). The low mean adsorption energy obtained from the D\u0026ndash;R model (E\u0026thinsp;=\u0026thinsp;3.79 kJ/mol) suggests that Pb\u003csup\u003e2+\u003c/sup\u003e adsorption is predominantly governed by physisorption mechanisms. Thermodynamic analysis revealed negative Gibbs free energy values (ΔG\u0026deg;=\u0026minus;6.72 to \u0026minus;\u0026thinsp;0.45 kJ/mol) at lower temperatures, confirming the spontaneous nature of Pb\u003csup\u003e2+\u003c/sup\u003e adsorption, while the negative enthalpy change (ΔH\u0026deg;=\u0026minus;60.75 kJ/mol) indicates an exothermic process. Reusability studies demonstrated that the AC/MnFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanocomposite retained over 66% of its initial adsorption efficiency after nine adsorption\u0026ndash;desorption cycles. The combination of high adsorption capacity, favorable kinetics, magnetic recoverability, and good regeneration performance highlights the AC/MnFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanocomposite as a promising and sustainable adsorbent for Pb\u003csup\u003e2+\u003c/sup\u003e remediation in water treatment applications.\u003c/p\u003e","manuscriptTitle":"Adsorptive removal of lead (Pb2+) ions using carbon–based magnetic nanocomposite","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-06 02:39:42","doi":"10.21203/rs.3.rs-9314991/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","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}}],"origin":"","ownerIdentity":"5863a67d-6975-4490-b11c-db7b84b3817d","owner":[],"postedDate":"April 6th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":65691078,"name":"Chemical Engineering"},{"id":65691079,"name":"Environmental Chemistry"},{"id":65691080,"name":"Materials Chemistry"}],"tags":[],"updatedAt":"2026-04-06T02:39:42+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-06 02:39:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9314991","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9314991","identity":"rs-9314991","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}