{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T04:59:52Z","timestamp":1777006792715,"version":"3.51.4"},"reference-count":74,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T00:00:00Z","timestamp":1776211200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Aligned CS\/Rx aerogels were fabricated by inducing non-directional ice growth (freeze-molding) followed by low-temperature curing, resulting in monoliths with interconnected channels, a high void fraction, and moldability. The swelling index (S%) was calculated to be 1029, the apparent density 0.496 g\u00b7cm\u22123, and the estimated porosity 90% based on micrographic analysis. Aerogels have mechanical behavior Shore A hardness greater than 25. Batch metal removal tests were performed (10 mL, 100 mg\u00b7L\u22121 Cr(VI), 0.19 g adsorbent, 24 h, and pH 5\u20135.5), and the material achieved 95% metal removal. Additional kinetic and isothermal results were obtained using CS85R15 on a packed column (20 to 140 mg\u00b7L\u22121, 1000 mL Cr(VI), 0.80 g adsorbent, 24 h, and pH 5\u20135.5). Equilibrium data were consistent with a heterogeneous surface hosting a specific site, as reflected in the joint Freundlich\/Langmuir fit (qmax 100.8 mg\u00b7g\u22121 for Langmuir). This confirmed the preservation of chitosan functionalities (\u2013OH\/\u2013NH) after processing, while XPS detected chromium on the surface with signals consistent with the partial reduction of Cr(VI) to Cr(III) on the aerogel surface. This highlights the relevance of adsorption-based technologies for water remediation, where high-porosity and low-density materials allow for short diffusion pathways and capture electrostatics by protonated amines and redox conversion of hazardous substances. The soft-cure freeze-molding technique is simple, scalable, and compatible with packed-bed\/column operation, providing a material platform for tailoring the microstructure (sheets and channels) and surface chemistry to regenerable sorbents for industrial wastewater treatment.<\/jats:p>","DOI":"10.3390\/gels12040330","type":"journal-article","created":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T15:56:56Z","timestamp":1776268616000},"page":"330","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Freeze-Cast Chitosan\/Resole Aerogels: Effect of Resole Fraction on Properties and Their Efficiency for Cr(VI) Uptake"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-0040-5100","authenticated-orcid":false,"given":"Jean","family":"Flores-G\u00f3mez","sequence":"first","affiliation":[{"name":"Departamento de Agua y Energ\u00eda, Centro Universitario de Tonal\u00e1, Universidad de Guadalajara, Tonal\u00e1 45425, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8272-0495","authenticated-orcid":false,"given":"Milton","family":"V\u00e1zquez-Lepe","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda de Proyectos, Centro Universitario de Ciencias Exactas e Ingenier\u00edas, Universidad de Guadalajara, Zapopan 45100, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-5533-8949","authenticated-orcid":false,"given":"\u00c1lvaro de Jes\u00fas","family":"Mart\u00ednez-G\u00f3mez","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda Qu\u00edmica, Centro Universitario de Ciencias Exactas e Ingenier\u00edas, Universidad de Guadalajara, Guadalajara 44430, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9211-5862","authenticated-orcid":false,"given":"V\u00edctor Hugo","family":"Romero-Arellano","sequence":"additional","affiliation":[{"name":"Departamento de Ciencias B\u00e1sicas Aplicadas e Ingenier\u00eda, Centro Universitario de Tonal\u00e1, Universidad de Guadalajara, Tonal\u00e1 45425, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0682-5102","authenticated-orcid":false,"given":"Juan Morales","family":"Rivera","sequence":"additional","affiliation":[{"name":"Departamento de Agua y Energ\u00eda, Centro Universitario de Tonal\u00e1, Universidad de Guadalajara, Tonal\u00e1 45425, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/s13201-018-0661-6","article-title":"Removal of Heavy Metals and Pollutants by Membrane Adsorption Techniques","volume":"8","author":"Khulbe","year":"2018","journal-title":"Appl. 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