Electro-oxidation of As(III) with dimensionally-stable and conductive-diamond anodes

In this work, arsenic oxidation by an electrochemical process was studied in a batch bench-scale electrolysis plant equipped with mono- and bi-compartment cells, dimensionally-stable anodes (DSAs) and conductive-diamond anodes (CDAs). The results demonstrate that the electrolysis is an adequate technology to transform As(III) into As(V) species, which is an important pre-treatment stage for removing of arsenic from water using technologies such as coagulation or electro-coagulation. The process requires large current densities in non-divided cells to obtain a good As(V)/As(III) ratio, but it can be more efficiently performed at low current densities in cells divided by cationic membranes. The presence of chlorides or sulphates can significantly affect the results due to the formation of powerful oxidants that contribute to the net oxidation process. (C) 2011 Elsevier B.V. All rights reserved.