Photoelectrocatalytic degradation of pharmaceutical carbamazepine using Sb-doped Sn 80% -W 20% -oxide electrodes

Abstract

Abstract The continuous release of pharmaceutical compounds in the environment is of concern due to their potential toxicological effects on living organisms, even at low concentrations. The insufficient removal of bioactive contaminants such as pharmaceuticals by conventional wastewater treatment processes has led scientists to investigate and develop efficient technologies such as advanced oxidation processes (AOPs) to address the issue. The objective of the present work was to study the applicability of thermally-prepared Sb-doped Sn 80% -W 20% -oxide thin film coated electrodes for the photoelectrocatalytic degradation of a recalcitrant pharmaceutical compound, carbamazepine (CBZ). The efficiency of photolytic and photocatalytic processes for removal of CBZ were also evaluated for comparison. The formation of transformation products was investigated and the results showed lower levels of transformation products in the water treated by the photoelectrocatalytic method compared to the photolytic and photocatalytic methods, by the end of 60-min treatment. This suggests a potentially lower overall toxicity of the final solution treated by the photoelectrocatalytic method. An estimation of the energy consumption to reach an order of magnitude reduction in the concentration of CBZ for each type of process indicated a lower energy requirement for the photoelectrocatalytic method, with the highest energy efficiency observed at the applied current density of 6 mA/cm 2 .