The electrocatalytic reduction and removal of arsenate by poly(aniline- co-o-aminophenol)

Abstract

Poly(aniline- co-o-aminophenol) (PANOA) deposited on the glassy carbon (GC) electrode was first used to investigate the electrocatalytic reduction of arsenate in a NaCl solution. The electrocatalytic evidence came from the pronounced increase in the current of arsenate reduction at the PANOA/GC electrode compared to the bare GC electrode under the same conditions. In the latter case the reduction current was small, indicating that arsenate is electrochemically inactive at the bare GC electrode. The catalytic activity of PANOA depended on the pH in the range 5.6–7.0, which is related to the effect of pH on the redox activity of PANOA and the dissociated form of arsenate in the solution. In addition, the electrochemical activity of PANOA was found to increase in a solution containing arsenate, which was caused by the increase in both the unpaired spin density of PANOA and the pH buffer capacity of the solution due to the presence of arsenate. The XPS data indicated that PANOA can be used to remove arsenate from the solution.