{"paper_id":"30f6b17c-cf0d-43c2-8fe4-e43207345369","body_text":"Removal of hexavalent chromium ion from aqueous solution using the light fraction of padma river sand adsorbent: Studies on equilibrium, kinetics, and thermodynamics | 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 Removal of hexavalent chromium ion from aqueous solution using the light fraction of padma river sand adsorbent: Studies on equilibrium, kinetics, and thermodynamics Md. Nuruzzaman, Firoz Ahmed, Md. Ibrahim H. Mondal This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8065230/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Mar, 2026 Read the published version in Environmental Science and Pollution Research → Version 1 posted 6 You are reading this latest preprint version Abstract This study investigates the removal of hexavalent chromium (Cr(VI)) from aqueous solutions using the light fraction of Padma River sand as a low-cost natural adsorbent. The adsorbent was characterized through FTIR, XRD, FESEM, and WD-XRF analyses, confirming its composition to be primarily quartz and muscovite, with no hazardous components. Batch adsorption experiments were performed to examine the influence of pH, contact time, adsorbent dosage, and temperature. Optimal Cr(VI) removal occurred at pH 2, with an adsorption capacity of 4.9128 mg/g. Adsorption kinetics followed the pseudo-second-order model, while equilibrium data best fitted the Langmuir isotherm, indicating monolayer adsorption. Thermodynamic analysis revealed that the process is spontaneous and exothermic, with a negative Gibbs free energy (ΔG° = –4.02 kJ/mol) and enthalpy change (ΔH° = –19.62 kJ/mol). WD-XRF confirmed chromium deposition on the adsorbent post-treatment. Comparative assessment with other sand-based adsorbents highlights the superior performance of the light fraction of Padma River sand. These findings suggest its potential as an efficient, sustainable material for Cr(VI) removal in water treatment systems, especially in resource-constrained settings. Hexavalent Chromium Padma River Sand Adsorption Kinetics Langmuir Isotherm Pseudo-Second-Order Model Thermodynamic Analysis Full Text Cite Share Download PDF Status: Published Journal Publication published 28 Mar, 2026 Read the published version in Environmental Science and Pollution Research → Version 1 posted Editorial decision: Major Revision 30 Jan, 2026 Reviewers agreed at journal 17 Dec, 2025 Reviewers invited by journal 27 Nov, 2025 Editor invited by journal 25 Nov, 2025 Editor assigned by journal 13 Nov, 2025 First submitted to journal 12 Nov, 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-8065230\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":551614221,\"identity\":\"6b1957bb-0040-4a33-a87f-3ef96d8ea7ae\",\"order_by\":0,\"name\":\"Md. Nuruzzaman\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Polymer and Textile Research Lab., Department of Applied Chemistry and Chemical Engineering, University of Rajshahi. 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The adsorbent was characterized through FTIR, XRD, FESEM, and WD-XRF analyses, confirming its composition to be primarily quartz and muscovite, with no hazardous components. Batch adsorption experiments were performed to examine the influence of pH, contact time, adsorbent dosage, and temperature. Optimal Cr(VI) removal occurred at pH 2, with an adsorption capacity of 4.9128 mg/g. Adsorption kinetics followed the pseudo-second-order model, while equilibrium data best fitted the Langmuir isotherm, indicating monolayer adsorption. Thermodynamic analysis revealed that the process is spontaneous and exothermic, with a negative Gibbs free energy (ΔG° = –4.02 kJ/mol) and enthalpy change (ΔH° = –19.62 kJ/mol). WD-XRF confirmed chromium deposition on the adsorbent post-treatment. Comparative assessment with other sand-based adsorbents highlights the superior performance of the light fraction of Padma River sand. These findings suggest its potential as an efficient, sustainable material for Cr(VI) removal in water treatment systems, especially in resource-constrained settings.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Removal of hexavalent chromium ion from aqueous solution using the light fraction of padma river sand adsorbent: Studies on equilibrium, kinetics, and thermodynamics\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2025-12-01 10:09:39\",\"doi\":\"10.21203/rs.3.rs-8065230/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Major Revision\",\"date\":\"2026-01-30T07:42:17+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"\",\"date\":\"2025-12-17T09:58:42+00:00\",\"index\":0,\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2025-11-27T08:39:41+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvited\",\"content\":\"Environmental Science and Pollution Research\",\"date\":\"2025-11-25T11:00:14+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2025-11-14T04:41:30+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"Environmental Science and Pollution Research\",\"date\":\"2025-11-12T11:47:57+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"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\":\"b369e78f-535e-4661-98f0-80e43e957271\",\"owner\":[],\"postedDate\":\"December 1st, 2025\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"published-in-journal\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-03-30T16:16:50+00:00\",\"versionOfRecord\":{\"articleIdentity\":\"rs-8065230\",\"link\":\"https://doi.org/10.1007/s11356-026-37622-1\",\"journal\":{\"identity\":\"environmental-science-and-pollution-research\",\"isVorOnly\":false,\"title\":\"Environmental Science and Pollution Research\"},\"publishedOn\":\"2026-03-28 16:08:45\",\"publishedOnDateReadable\":\"March 28th, 2026\"},\"versionCreatedAt\":\"2025-12-01 10:09:39\",\"video\":\"\",\"vorDoi\":\"10.1007/s11356-026-37622-1\",\"vorDoiUrl\":\"https://doi.org/10.1007/s11356-026-37622-1\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-8065230\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-8065230\",\"identity\":\"rs-8065230\",\"version\":[\"v1\"]},\"buildId\":\"XKTyCvWXoU3ODBz1xrDgd\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}