Raw Clay–Based Fenton Catalysis for Dark Blue Reactive Dye Removal: Experimental Assessment Supported by DFT Insights

Raw Clay–Based Fenton Catalysis for Dark Blue Reactive Dye Removal: Experimental Assessment Supported by DFT 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 Article Raw Clay–Based Fenton Catalysis for Dark Blue Reactive Dye Removal: Experimental Assessment Supported by DFT Insights Ghazza Masmoudi, Sahar Mazgar, Hatem Dhaouadi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8978065/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 The present research focuses on the degradation of azo dye Dark Blue (DB) using natural clay as a catalyst source for heterogeneous Fenton reaction. The main objectives of this study were to evaluate the influence of pH on the degradation efficiency over time, to assess the contribution of adsorption on the clay surface, and to investigate the molecular interactions between DB and clay. The optimization of the pH value showed that maximum removal was observed at pH 4. Comparative analyses with classical Fenton reactions at pH = 3 and pH = 4 and heterogenous Fenton reaction assisted with ultrasound confirmed the dominant catalytic role of the clay, while adsorption accounted for only 8% of the overall dye removal. To gain further insight into the adsorption mechanisms, Density Functional Theory (DFT) calculations using the cluster approximation were performed to model the molecular and electronic interactions between DB and clay, predominantly composed of kaolinite. The DFT results confirmed that adsorption is driven by physical interactions and highlight a clear distinction in adsorption mechanisms: while DB anchors to the KLNT(Si-O) surface through localized hydrogen bonds, its stabilization on the KLNT(Al-O) facet arises from a collective contribution of weaker non-covalent interactions. Physical sciences/Chemistry Earth and environmental sciences/Environmental sciences Physical sciences/Materials science Heterogeneous Fenton Catalysis Wastewater Treatment Raw Clay Dark Blue Dye DFT 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. 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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-8978065","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":613631481,"identity":"f3efc45c-d91d-4c2b-8791-b9eff3d4f3e7","order_by":0,"name":"Ghazza Masmoudi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBUlEQVRIiWNgGAWjYDACCRQem4QcewOpWox5DkDZPERqYUjsIaRFPrr58ccfNQzR/P2nEx/zlFmk9/CfTmCu3HGYwV4auxMN7xwzMJA4xpA740buZmOecxK5PRK5GxjPnjnMwCNzALuWGQkGCQZsDLkNN3i3SfO2SeTul+DdwNjYBtQikYBDS/qHAwn/GHLnnz8L1pLOw38WvxZ5iRzDhoNtDLkbDuSCtSTwANl4tRhI5BQzNvZJ5G4E+sVwzjkJQ5BfDja2pfPw3MBhy4z0zR9/fLPJnXf+7MYHb8rq5IEO2/iwsc1ajn0GDlsgoYIaOwwgQZwxKd+AS2YUjIJRMApGAQwAAOY4XQ0JuB+VAAAAAElFTkSuQmCC","orcid":"","institution":"University of Monastir","correspondingAuthor":true,"prefix":"","firstName":"Ghazza","middleName":"","lastName":"Masmoudi","suffix":""},{"id":613631482,"identity":"26ce0d0b-3d85-40c5-bca0-7b686602e3b8","order_by":1,"name":"Sahar Mazgar","email":"","orcid":"","institution":"University of Monastir","correspondingAuthor":false,"prefix":"","firstName":"Sahar","middleName":"","lastName":"Mazgar","suffix":""},{"id":613631483,"identity":"aba2f080-6ccc-4f7e-b99d-9eeca610c8e3","order_by":2,"name":"Hatem Dhaouadi","email":"","orcid":"","institution":"University of Monastir","correspondingAuthor":false,"prefix":"","firstName":"Hatem","middleName":"","lastName":"Dhaouadi","suffix":""}],"badges":[],"createdAt":"2026-02-26 12:55:00","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8978065/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8978065/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106403129,"identity":"6c3b18b4-10ef-4789-b611-ead6de14ab11","added_by":"auto","created_at":"2026-04-08 09:13:38","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1239680,"visible":true,"origin":"","legend":"","description":"","filename":"ArticleFentonhtrogne.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8978065/v1_covered_74d3f85d-6fe7-4a23-a7bc-760296564021.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Raw Clay–Based Fenton Catalysis for Dark Blue Reactive Dye Removal: Experimental Assessment Supported by DFT Insights","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"Heterogeneous Fenton Catalysis, Wastewater Treatment, Raw Clay, Dark Blue Dye, DFT","lastPublishedDoi":"10.21203/rs.3.rs-8978065/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8978065/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe present research focuses on the degradation of azo dye Dark Blue (DB) using natural clay as a catalyst source for heterogeneous Fenton reaction. The main objectives of this study were to evaluate the influence of pH on the degradation efficiency over time, to assess the contribution of adsorption on the clay surface, and to investigate the molecular interactions between DB and clay. The optimization of the pH value showed that maximum removal was observed at pH 4. Comparative analyses with classical Fenton reactions at pH\u0026thinsp;=\u0026thinsp;3 and pH\u0026thinsp;=\u0026thinsp;4 and heterogenous Fenton reaction assisted with ultrasound confirmed the dominant catalytic role of the clay, while adsorption accounted for only 8% of the overall dye removal. To gain further insight into the adsorption mechanisms, Density Functional Theory (DFT) calculations using the cluster approximation were performed to model the molecular and electronic interactions between DB and clay, predominantly composed of kaolinite. 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