Removal of arsenic(V) from aqueous wastes by ion exchange with lewatit MP64 resin

Abstract

The use of ion exchange technology was studied to remove arsenic(V) from waters by Lewatit MP64 (anion exchanger) resin. Batch and column experimental tests were conducted to provide data for theoretical models and verify the system performance of the exchange process. Results of batch equilibrium tests indicated that Langmuir isotherm describes well the exchange process, whereas experimental data also provide evidence that, under the present experimental conditions, arsenic(V) adsorption onto Lewatit MP64 resin is film-diffusion controlled and obeys the pseudo-first-order kinetics law (pH 4–9). Adsorption results were compared with that obtained with multiwalled carbon nanotubes and other resins. On the other hand, the theoretical model used in the present investigation was found to predict reasonably well the ion exchange breakthrough performance. Arsenic can be eluted with sodium chloride solutions to afford the ultimate arsenic recuperation via precipitation to as arsenate salts or even crystalline scorodite.