Enhanced Selective Removal of Cd (II) from Aqueous Solution by Dual Ionic Thermosensitive Hydrogel: Synthesis, Characterization and Isotherm Analysis

Enhanced Selective Removal of Cd (II) from Aqueous Solution by Dual Ionic Thermosensitive Hydrogel: Synthesis, Characterization and Isotherm Analysis | 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 Enhanced Selective Removal of Cd (II) from Aqueous Solution by Dual Ionic Thermosensitive Hydrogel: Synthesis, Characterization and Isotherm Analysis Eva Oktavia Ningrum, Wirawan Ciptonugroho, Takehiko Gotoh, Saidah Altway, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6704096/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 In this study, hydrogels based on N-isopropylacrylamide (NIPAM) copolymerized with acrylic acid (AA) or with chitosan (Chi) were synthesized at various temperatures (30°C and 50°C) and evaluated for their structural, swelling, and adsorption properties. FTIR analysis confirmed successful copolymerization and indicated thermal effects on functional group expression. Swelling tests revealed that hydrogels synthesized at 30°C exhibited significantly higher equilibrium swelling ratios, attributed to the expanded polymer network below NIPAM's LCST. SEM and BET analyses demonstrated that lower synthesis temperatures promoted a larger surface area and enhanced porosity. Adsorption experiments using CdCl₂ solutions showed that blended gels achieved equilibrium within 4 h. In addition, the blending of NIPAM/AA and NIPAM/Chi at a synthesis temperature of 30°C resulted in the highest swelling ratio of 5.8 and the highest removal of 91.90%. Isothermal modelling revealed that the Freundlich model best described the adsorption behaviour, suggesting multilayer and heterogeneous surface adsorption. The kinetics study for cadmium (Cd2+) and chloride (Cl-) ion adsorptions was best fit with the Avrami kinetic model, describing the adsorption of Cd2 + and Cl- ions occurred through both physical and chemical mechanisms sustainably. These findings support the development of temperature-sensitive and eco-friendly hydrogel-based adsorbents for heavy metal remediation in aqueous environments. Acrylic Acid Adsorbent Chitosan Gel NIPAM 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. 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-6704096","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":524739365,"identity":"70438c63-8ebf-49fe-9679-b12e0032de74","order_by":0,"name":"Eva Oktavia 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Analysis","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":"Acrylic Acid, Adsorbent, Chitosan, Gel, NIPAM","lastPublishedDoi":"10.21203/rs.3.rs-6704096/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6704096/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, hydrogels based on N-isopropylacrylamide (NIPAM) copolymerized with acrylic acid (AA) or with chitosan (Chi) were synthesized at various temperatures (30\u0026deg;C and 50\u0026deg;C) and evaluated for their structural, swelling, and adsorption properties. FTIR analysis confirmed successful copolymerization and indicated thermal effects on functional group expression. Swelling tests revealed that hydrogels synthesized at 30\u0026deg;C exhibited significantly higher equilibrium swelling ratios, attributed to the expanded polymer network below NIPAM's LCST. SEM and BET analyses demonstrated that lower synthesis temperatures promoted a larger surface area and enhanced porosity. Adsorption experiments using CdCl₂ solutions showed that blended gels achieved equilibrium within 4 h. In addition, the blending of NIPAM/AA and NIPAM/Chi at a synthesis temperature of 30\u0026deg;C resulted in the highest swelling ratio of 5.8 and the highest removal of 91.90%. Isothermal modelling revealed that the Freundlich model best described the adsorption behaviour, suggesting multilayer and heterogeneous surface adsorption. The kinetics study for cadmium (Cd2+) and chloride (Cl-) ion adsorptions was best fit with the Avrami kinetic model, describing the adsorption of Cd2\u0026thinsp;+\u0026thinsp;and Cl- ions occurred through both physical and chemical mechanisms sustainably. These findings support the development of temperature-sensitive and eco-friendly hydrogel-based adsorbents for heavy metal remediation in aqueous environments.\u003c/p\u003e","manuscriptTitle":"Enhanced Selective Removal of Cd (II) from Aqueous Solution by Dual Ionic Thermosensitive Hydrogel: Synthesis, Characterization and Isotherm Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-07 08:17:28","doi":"10.21203/rs.3.rs-6704096/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":"7e5f09f9-4e4e-4a99-b97c-b722ca3605b4","owner":[],"postedDate":"October 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-10T20:08:13+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-07 08:17:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6704096","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6704096","identity":"rs-6704096","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}