{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T22:19:50Z","timestamp":1791929990546,"version":"4.3.4"},"reference-count":50,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,1]],"date-time":"2025-08-01T00:00:00Z","timestamp":1754006400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003566","name":"Ministry of Oceans and Fisheries","doi-asserted-by":"publisher","award":["KIMST-20220128"],"award-info":[{"award-number":["KIMST-20220128"]}],"id":[{"id":"10.13039\/501100003566","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>A metal-ion-free method was developed to prepare \u03ba-carrageenan\/cellulose hydrogel beads for efficient cationic dye removal. The beads were fabricated using a mixture of 1-ethyl-3-methylimidazolium acetate and N,N-dimethylformamide as the solvent system, followed by aqueous ethanol-induced phase separation. This process eliminated the need for metal-ion crosslinkers, which typically neutralize anionic sulfate groups in \u03ba-carrageenan, thereby preserving a high density of accessible binding sites. The resulting beads formed robust interpenetrating polymer networks. The initial swelling ratio reached up to 28.3 g\/g, and even after drying, the adsorption capacity remained over 50% of the original. The maximum adsorption capacity for crystal violet was 241 mg\/g, increasing proportionally with \u03ba-carrageenan content due to the higher surface concentration of anionic sulfate groups. Kinetic and isotherm analyses revealed pseudo-second-order and Langmuir-type monolayer adsorption, respectively, while thermodynamic parameters indicated that the process was spontaneous and exothermic. The beads retained structural integrity and adsorption performance across pH 3\u20139 and maintained over 90% of their capacity after five reuse cycles. These findings demonstrate that \u03ba-carrageenan\/cellulose hydrogel beads prepared via a metal-ion-free strategy offer a sustainable and effective platform for cationic dye removal from wastewater, with potential for heavy metal ion adsorption.<\/jats:p>","DOI":"10.3390\/gels11080596","type":"journal-article","created":{"date-parts":[[2025,8,5]],"date-time":"2025-08-05T08:46:55Z","timestamp":1754383615000},"page":"596","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Metal-Ion-Free Preparation of \u03ba-Carrageenan\/Cellulose Hydrogel Beads Using an Ionic Liquid Mixture for Effective Cationic Dye Removal"],"prefix":"10.3390","volume":"11","author":[{"given":"Dojin","family":"Kim","sequence":"first","affiliation":[{"name":"Advanced Materials Program, Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dong Han","family":"Kim","sequence":"additional","affiliation":[{"name":"Advanced Materials Program, Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeong Eun","family":"Cha","sequence":"additional","affiliation":[{"name":"Advanced Materials Program, Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saerom","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6789-477X","authenticated-orcid":false,"given":"Sang Hyun","family":"Lee","sequence":"additional","affiliation":[{"name":"Advanced Materials Program, Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"},{"name":"Department of Biological Engineering, Konkuk University, Seoul 05029, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.jare.2013.07.006","article-title":"Hydrogel: Preparation, characterization, and applications: A review","volume":"6","author":"Ahmed","year":"2015","journal-title":"J. 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