Gels based on calcium alginate/pillared bentonite: structural characterization and their use as cadmium removal agent

SCHMIDT, LUCIA NATASHA; HORST, MARÍA FERNANDA; LENCINA, MARÍA MALVINA SOLEDAD; LÓPEZ, OLIVIA VALERIA; NINAGO, MARIO DANIEL

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING

TAYLOR & FRANCIS INC

Año: 2022 p. 1 - 11

1093-4529

In this work, calcium alginate hydrogels with natural and pillared bentonites (0.5 and 5% w/w)were synthetized in two geometries (disks and beads) and their capacity to adsorb cadmium ionfrom aqueous media was evaluated. Pillarization effect on bentonite morphology was evidencedby SEM, XRD, LD and BET isotherms. Structure and swelling capacity of hydrogels were determined,showing that hydrogels beads with pillared clays presented the higher ability to retainwater. Regarding cadmium adsorption capacity, the effect of pH media (3, 5 and 7), the contacttime (0 to 320 min.) and the initial cadmium ion concentration (6 to 42mg/L) were studiedemploying hydrogel beads. Regardless bentonite type and concentration, the optimal pH cadmiumadsorption was 7, reaching the highest adsorption capacity (93%) for hydrogel with 0.5% naturalbentonite. Besides, the equilibrium adsorption time was reached at 120 min for all studied hydrogelsand experimental data fitted with a pseudo-second order kinetic model.