Experimental and Kinetic modeling of As (V) adsorption on Granular Ferric Hydroxide and Laterite

This work aims to study the As (V) removal in aqueous solutions using Granular Ferric Hydroxide (GFH) and Natural Laterite at ambient temperature. Column experiments were conducted to investigate the As (V) removal mechanism and effects of parameters affecting the adsorption were studied to follow the adsorption kinetics. Maximum removal of arsenic (99.99% and 99.5%) was achieved at 15 min of contact time with an initial concentration of 20 mg/L using 10 g of GFH and laterite in 50 ml volume of solution, respectively. From the isotherm models study, i.e. Langmuir, Freundlich and Dubinin - Radushkevich, the adsorption process in our study followed best Freundlich isotherm. The study of isotherms showed that the adsorption was physical, spontaneous with GFH while endothermic using laterite, respectively. The kinetics study showed that the adsorption process fits with a pseudo-second order reaction model using both adsorbents. The adsorption column design was done using Logit method and the obtained values of adsorption rate coefficient (K) and adsorption capacity coefficient (N) were 3.2 10-4 L/(mg. min) and 8968.46 mg/L, respectively for GFH and 1.43 10-3 L/(mg. min), 977.19 mg/L using laterite. The fixed bed column studies showed that Granular Ferric Hydroxide and Laterite were efficient in small-scale for As (V) removal.

کلیدواژه ها:

Arsenic ، Removal ، Granular Ferric Hydroxide ، Laterite ، aqueous solutions