Multifunctional carboxymethyl cellulose-dextran sulfate/AgNPs@zeolite hydrogel beads for basic red 46 and methylene blue dyes removal and water disinfection control

Abstract

Herein, novel bionanocomposite hydrogels based on sodium carboxymethyl cellulose-dextran sulfate and silver nanoparticle-modified zeolite (CMC-DS-AgZ) were successfully fabricated and inspected for the removal of highly toxic basic red 46 (BR46) and methylene blue (MB) cationic dyes in single and binary systems. Silver nanoparticles (AgNPs) were synthesized by a green process using Curcuma longa (C. longa) tuber extract in situ in zeolite. Swelling at various pH levels and disinfection ability tests were also performed. Incorporating AgZ into hydrogels not only increases the roughness and thermal stability of the hydrogel, but also significantly improves adsorption capacity and induced significant antimicrobial properties. Indeed, the optimized hydrogels prepared with 3 % AgZ yielded levels of around 344.82 and 454.55 mg g−1 for BR46 and MB dyes when using 1 g/L adsorbent dose, pH 7 and 6 h contact time. Experimental data modeling revealed that the adsorption process was well described by the pseudo-second-order kinetic and Langmuir isotherm models (R2 > 0.99). In case of binary system, conversely to BR46 adsorption which was slightly affected, MB adsorption was considerably reduced by simultaneous presence of both dyes in solution. Nevertheless, it was found that the bionanocomposite could effectively and simultaneously remove cationic dyes up to five adsorption/desorption cycles.