Eco-Engineered Alginate Zr/Mn Hydrogel for Ultra-Efficient Cr(VI) Removal: Insights into Mechanism and Performance

Eco-Engineered Alginate Zr/Mn Hydrogel for Ultra-Efficient Cr(VI) Removal: Insights into Mechanism and Performance | 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 Eco-Engineered Alginate Zr/Mn Hydrogel for Ultra-Efficient Cr(VI) Removal: Insights into Mechanism and Performance Laila S. Alqarni, Jari S. Algethami, Faisal K. Algethami, Rachid EL Kaim Billah, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7330088/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 11 You are reading this latest preprint version Abstract A novel hydrogel composite, Na-ALG@Zr/Mn, was synthesized and tested for its ability to remove toxic hexavalent chromium from water. Advanced characterization techniques, including FTIR, XRD, BET, SEM–EDX, TEM, and XPS, confirmed the formation of a mesoporous structure, effective surface interactions, and successful incorporation of metal oxides. The composite showed outstanding efficiency at low pH (3–4), mainly due to strong electrostatic attraction and redox reactions that reduce Cr(VI) to Cr(III). Kinetic studies align closely with the fractal pseudo-second order model, suggesting that chemisorption primarily drives the process. Isotherm analysis shows the Liu model as the best fit, with a maximum adsorption capacity of 688.8 mg/g at 298 K. Thermodynamic evaluation indicates the adsorption is spontaneous and endothermic, evidenced by negative Gibbs free energy and positive enthalpy change. XPS spectra confirm the reduction of Cr(VI) and its strong interaction with functional groups on the composite surface. To gain a clearer understanding of the electronic properties and how Cr(VI) adsorbs onto the synthesized Na-ALG@Zr/Mn nanocomposite, we performed DFT (Density Functional Theory) calculations with the B3LYP/6-311G(d,p) basis set. These outcomes emphasize Na-ALG@Zr/Mn's potential as a cost-effective, environmentally friendly, and efficient adsorbent for removing Cr(VI) from contaminated water. Sodium alginate ZrO₂/MnO₂ Batch adsorption experiments Density Functional Theory Full Text Additional Declarations No competing interests reported. Supplementary Files SupdataVF.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 14 Dec, 2025 Reviews received at journal 25 Nov, 2025 Reviewers agreed at journal 19 Nov, 2025 Reviews received at journal 19 Nov, 2025 Reviewers agreed at journal 18 Nov, 2025 Reviewers agreed at journal 05 Nov, 2025 Reviewers agreed at journal 04 Nov, 2025 Reviewers invited by journal 03 Nov, 2025 Editor assigned by journal 22 Aug, 2025 Submission checks completed at journal 11 Aug, 2025 First submitted to journal 08 Aug, 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. 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-7330088","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":540737054,"identity":"633be1fa-4491-45eb-9658-80d9da4c2b4c","order_by":0,"name":"Laila S. 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