Modification of Sodium Bentonitic Clay Used in Zinc Ion Adsorption

Abstract

In this study, it was evaluated the potential use of commercial sodium bentonitic clay, called Fluidgel, chemically and thermally treated, as an adsorbent in the removal of zinc ions from aqueous effluents. The chemical treatment was carried out with 10 g of clay dispersed in 100 mL of acetic acid 4 %. The heat treatment was obtained by calcination at 750 °C for 24 hours in muffle. The adsorption experiments were performed in thermostatic bath system and fixed bed, both based on preliminary study of metallic cationic speciation. The kinetics of zinc ions adsorption by acid-treated clay was rapid, requiring a minimum time of 60 min to reach equilibrium. The adsorbed amount and percentage of total zinc removal, at equilibrium time, was 0.06 mmol/g and 45 %, respectively, using the acid-treated clay. There was no removal of zinc by Fluidgel calcined clay in bath system, but in fixed bed it was obtained the total amount of zinc removal of 0.11 mmol/g and 41 % of percentage of removal.