Keywords: arsenic desorption, synthetic leachate, TCLP, toxicity characteristic leaching procedure, laterite leaching, leachability index, desorption kinetics, adsorption
Desorption kinetics and leaching study of arsenic from arsenite/arsenate-loaded Natural Laterite
Desorption kinetics of arsenite- and arsenate-loaded Natural Laterite (NL) is performed under varying NaOH concentration (0.05-0.3 mol/L) and pH (4.0-11.0) of the desorption medium. The kinetic desorption data are well fitted to pseudo-second order kinetic model. The leaching of NL under aqueous medium is performed in the pH range of 2-12. Separately arsenite- and arsenate-loaded NL is leached according to Toxicity Characteristic Leaching Procedure (TCLP) protocol. However, recent studies indicate that TCLP significantly underestimate the leaching behaviour of arsenic. So, arsenic leaching from arsenic-loaded NL is conducted under synthetic leachate condition and results are compared with TCLP results.