Adsorption of Pb2+ ion using coal fly ash/g-C3N4/Bi2O2CO3 and re-use of spent adsorbent for photocatalytic and forensic applications

Adsorption of Pb2+ ion using coal fly ash/g-C3N4/Bi2O2CO3 and re-use of spent adsorbent for photocatalytic and forensic applications | 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 Adsorption of Pb2 + ion using coal fly ash/g-C 3 N 4 /B i2 O 2 CO 3 and re-use of spent adsorbent for photocatalytic and forensic applications MEH Ahamed, Kriveshini Pillay This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8637590/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Here, the application of a novel coal fly ash/graphitic carbon nitride/Bismuth oxy carbonate (CFA/g-C 3 N 4 /Bi₂O₂CO₃) composite for Pb(II) removal from aqueous solutions is reported. The composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and other techniques. The factors affecting the Pb(II) removal performance in batch adsorption experiments, including contact time, adsorbent dosage, and solution pH, were evaluated using the response surface methodology (RSM) approach with central composite design (CCD). The analysis revealed that under optimal conditions for Pb(II) removal (107.6 min, 24.35 mg, pH 6.62, at 25 ºC), Pb(II) removal performance reached 100%. Kinetic studies indicated a rapid adsorption process, well-conformed with the pseudo-second order model. Isotherm analysis affirmed the applicability of the Langmuir model, suggesting a monolayer adsorption with a maximum adsorption capacity of 60.29 mg g⁻¹. The adsorption process was endothermic and spontaneous. The Pb 2+ ion-loaded spent adsorbent (CFA/g-C 3 N 4 /Bi 2 O 2 CO 3 @Pb 2+ ) was then reused to degrade rhodamine B (RhB). The photocatalytic experiments for RhB over CFA/g-C₃N₄/Bi₂O₂CO₃@Pb²⁺ under optimal conditions demonstrated excellent photocatalytic performance (< 99%) and high reusability (up to 5 cycles). This highlights that the CFA/g-C 3 N 4 /Bi₂O₂CO₃@Pb²⁺ is a potential photocatalyst for dye remediation in wastewater treatment applications. Additionally, CFA/g-C 3 N 4 /Bi₂O₂CO₃@Pb²⁺ demonstrated to be responsive for latent fingerprint (LFP) detection on a variety of substrates. As a result, it is a useful labeling agent for LFP detection in forensic authentication. Pb2+ Coal fly ash Spent adsorbent Central composite design Photocatalyst RhB Latent Fingerprint Full Text Supplementary Files Supplementarydata002.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 24 Feb, 2026 Reviewers invited by journal 24 Feb, 2026 Editor invited by journal 05 Feb, 2026 Editor assigned by journal 30 Jan, 2026 First submitted to journal 27 Jan, 2026 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. 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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-8637590","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":596506643,"identity":"afdda5a8-a767-44aa-a1d1-28d8edef9866","order_by":0,"name":"MEH Ahamed","email":"","orcid":"","institution":"University of Johannesburg - Doornfontein Campus","correspondingAuthor":false,"prefix":"","firstName":"MEH","middleName":"","lastName":"Ahamed","suffix":""},{"id":596506644,"identity":"334c359f-e9e0-42ef-a2ed-0cb3910c2f90","order_by":1,"name":"Kriveshini Pillay","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYBACCQbGBiB1gIeBmYHxAQMPiVqYDYjUAgYHQASbBFEOk5x9uE3iw587MubsvMeqeWQY5Pkb2B9+wKdFmi+xTXJm2zMey2a+tNs8PAyGMw4wJOO1To6HsdmYt+Ewj8FhHjOQFsYNQGcS1vLnD0RLMVCL/QYGxuYfeB3Gw9j4mIENooUZqCVxAwMz/nCQ7GFsfNjbBtLClyw5h0ciecZhNjYLfFokzrA/OPDjz2F7g/NnD35422Nj29/e/vgGPi1IABiNjD1AJzETqR6ihQGvv0fBKBgFo2CkAgC3mUBUBE0vWAAAAABJRU5ErkJggg==","orcid":"","institution":"University of Johannesburg - Doornfontein Campus","correspondingAuthor":true,"prefix":"","firstName":"Kriveshini","middleName":"","lastName":"Pillay","suffix":""}],"badges":[],"createdAt":"2026-01-19 09:35:50","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8637590/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8637590/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104398348,"identity":"571bf192-6ffe-443b-92e8-43c88181b966","added_by":"auto","created_at":"2026-03-11 12:01:57","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2407828,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript3correction1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8637590/v1_covered_a42692ab-ead1-4616-aa7c-c642eca87f96.pdf"},{"id":103545401,"identity":"05f34402-f847-45cd-9169-48f15b0f9231","added_by":"auto","created_at":"2026-02-26 23:06:41","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":205180,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarydata002.docx","url":"https://assets-eu.researchsquare.com/files/rs-8637590/v1/5b21a4b67c99264195f59d31.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003eAdsorption of Pb2\u003csup\u003e+ \u003c/sup\u003eion using coal fly ash/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/B\u003csub\u003ei2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e and re-use of spent adsorbent for photocatalytic and forensic applications\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Pb2+, Coal fly ash, Spent adsorbent, Central composite design, Photocatalyst, RhB, Latent Fingerprint","lastPublishedDoi":"10.21203/rs.3.rs-8637590/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8637590/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eHere, the application of a novel coal fly ash/graphitic carbon nitride/Bismuth oxy carbonate (CFA/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/Bi₂O₂CO₃) composite for Pb(II) removal from aqueous solutions is reported. The composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and other techniques. The factors affecting the Pb(II) removal performance in batch adsorption experiments, including contact time, adsorbent dosage, and solution pH, were evaluated using the response surface methodology (RSM) approach with central composite design (CCD). The analysis revealed that under optimal conditions for Pb(II) removal (107.6 min, 24.35 mg, pH 6.62, at 25 \u0026ordm;C), Pb(II) removal performance reached 100%. Kinetic studies indicated a rapid adsorption process, well-conformed with the pseudo-second order model. Isotherm analysis affirmed the applicability of the Langmuir model, suggesting a monolayer adsorption with a maximum adsorption capacity of 60.29 mg g⁻\u0026sup1;. The adsorption process was endothermic and spontaneous. The Pb\u003csup\u003e2+\u003c/sup\u003e ion-loaded spent adsorbent (CFA/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/Bi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e@Pb\u003csup\u003e2+\u003c/sup\u003e) was then reused to degrade rhodamine B (RhB). The photocatalytic experiments for RhB over CFA/g-C₃N₄/Bi₂O₂CO₃@Pb\u0026sup2;⁺ under optimal conditions demonstrated excellent photocatalytic performance (\u0026lt;\u0026thinsp;99%) and high reusability (up to 5 cycles). This highlights that the CFA/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/Bi₂O₂CO₃@Pb\u0026sup2;⁺ is a potential photocatalyst for dye remediation in wastewater treatment applications. Additionally, CFA/g-C\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e/Bi₂O₂CO₃@Pb\u0026sup2;⁺ demonstrated to be responsive for latent fingerprint (LFP) detection on a variety of substrates. As a result, it is a useful labeling agent for LFP detection in forensic authentication.\u003c/p\u003e","manuscriptTitle":"Adsorption of Pb2+ ion using coal fly ash/g-C3N4/Bi2O2CO3 and re-use of spent adsorbent for photocatalytic and forensic applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-26 23:06:36","doi":"10.21203/rs.3.rs-8637590/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-02-24T21:22:23+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-24T19:40:02+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Environmental Science and Pollution Research","date":"2026-02-05T08:32:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-30T05:36:59+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Science and Pollution Research","date":"2026-01-28T00:06:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"668d373f-6f8e-4b54-8a4e-ad0d608863ce","owner":[],"postedDate":"February 26th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-26T23:06:36+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-26 23:06:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8637590","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8637590","identity":"rs-8637590","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}