Abstract
Adsorptive removal of selenate from aqueous phase using ZrIV-loaded orange waste gel was investigated. Adsorption kinetics showed that equilibrium was attained within 2 and 4 h for 12 and 23 mg/L of SeVI, respectively. A pseudo-second-order kinetic model was found to characterize the adsorption kinetics for all the initial selenium concentrations tested. Adsorption isotherms at various pH values were examined and the data fitted well with Langmuir model. The maximum sorption capacity was found to be 25 mg/g at optimum pH. The adsorption system was found to be favorable with separation factors between 0 and 1. Competitive adsorption by coexisting anions showed that chloride barely affected SeVI adsorption while phosphate and sulfate impeded SeVI adsorption. A ligand exchange mechanism was inferred for SeVI adsorption.
