The tanning industry is among the most environmentally harmful activities globally due to the pollution of lakes and rivers from its effluents. Hexavalent chromium, a metal in tannery effluents, has adverse effects on human health and ecosystems, requiring the development of removal techniques. This study assessed the efficacy of organobentonite/alginate hydrogel beads in removing Cr(VI) from a fixed-bed adsorption column system. The synthesized organobentonite (OBent) was encapsulated in alginate, utilizing calcium chloride as a crosslinking agent to generate hydrogel beads. The effects of the volumetric flow rate, bed height, and initial Cr(VI) concentration on a synthetic sample were analyzed in the experiments in fixed-bed columns. The fractal-like modified Thomas model showed a good fit to the experimental data for the asymmetric breakthrough curves, confirmed by the high correlation coefficients and low values. The application of organoclay/alginate hydrogel beads was confirmed with a wastewater sample from an artisanal tannery industry in Belén (Nariño, Colombia), in which a Cr(VI) removal greater than 99.81% was achieved. Organobentonite/alginate hydrogels offer the additional advantage of being composed of a biodegradable polymer (sodium alginate) and a natural material (bentonite-type clay), resulting in promising adsorbents for the removal of Cr(VI) from aqueous solutions in both synthetic and real water samples.
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http://dx.doi.org/10.3390/gels10120779 | DOI Listing |
J Biosci Bioeng
January 2025
Department of Chemical Systems Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. Electronic address:
The bioartificial pancreas, composed of a semi-permeable hydrogel encapsulating insulin-secreting cells, has attracted attention as a treatment for type 1 diabetes. In this study, we developed phospholipid polymer-modified alginate hydrogel beads that encapsulated spheroids of the pancreatic beta cell line MIN6. The hydrogel beads were composed of methacrylated alginic acid, which enabled both ionic and covalent cross-linking, resulting in a hydrogel that was more stable than conventional alginate hydrogels.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Chemistry Department, Faculty of Science, Damietta University, Damietta 34517, Egypt. Electronic address:
The VCo-LDH/CS hydrogel beads were created by combining VCo-layered double hydroxide (VCo-LDH) and chitosan (CS) using a cross-linking process with epichlorohydrin. These beads were specifically designed to remove tetracycline (TTC). To characterize the VCo-LDH/CS hydrogel beads, several analytical techniques were used, with PXRD, XPS, FESEM, EDX, and FT-IR.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University of Santiago de Compostela, 27002, Lugo, Spain.
The primary goal of the current work was to construct pH-sensitive nano and microcomposite hydrogel beads based on alginate (AL), carboxymethyl cellulose (CMC), biochar (BC), and two Moroccan clays: Ghassoul (swelling SW) and red (not swelling NSW) nano and microhybrid. The adsorbents, SW + AL, SW + AL + BC, SW + AL + CMC, NSW + AL, NSW + AL + BC, NSW + AL + CMC, AL, and AL + CMC were prepared for the adsorption of the antibiotic sulfadiazine (SDZ). The test samples were characterized using a variety of techniques, including X-Ray Diffraction (XRD), IR spectroscopy (FT-IR), and scanning electron microscopy (SEM), with the molecular structures of the studied additives geometrically optimized using the DFT/B3LYP method and the function 6-311G(d).
View Article and Find Full Text PDFCarbohydr Polym
March 2025
School of Environmental and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address:
Carbon dots (CDs) mediated g-CN (CN) is a promising visible-light-driven semiconductor in catalyzing peroxymonosulfate (PMS) for aqueous contaminants remediation. However, the poor dispersibility of powered catalyst and its challenging recyclability impede their broader application. Herein, we embedded FeN bridge within the g-CN framework and immobilized g-CN gel beads (CA/FNCCN) through a 3D cross-linking process with sodium alginate.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Chemical Engineering, Auburn University, 212 Ross Hall, Auburn, AL 36849, USA.
Cellulose microgel beads fabricated using the dropping technique suffer from structural irregularity and mechanical variability. This limits their translation to biomedical applications that are sensitive to variations in material properties. Ionic salts are often uncontrolled by-products of this technique, despite the known effects of ionic salts on cellulose assembly.
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