Diclofenac degradation by photocatalytically-assisted electrochemical method

Abstract

Diclofenac (DCF), a nonsteroidal antiinfammatory drug, is a micropollutant resistant to biodegradation. Consequently, it is necessary to apply processes that induce DCF biodegradabil- ity or get its mineralisation. The aim of this paper was the investigation of DCF degradation by a photocatalytically-assisted electrochemical method. Dimensionally stable anodes (DSA) consisting of Ti/RuO2-TiO2 and zeolite-supported TiO2 based on (Z-TiO2-Ag and Z1-TiO2) photocatalysts were used. The experiments were carried out by applying current densities of 75, 100 and 200 A/m2 simultaneously with UV irradiation for 60 and 120 min at concentration of the photocatalysts of 1 g/l. The concentration of DCF in the solutions that underwent degradation increased incrementally: 50, 100 and 200 mg/l. The process was followed by ultraviolet (UV) spectra recording and chemi- cal oxygen demand (COD-Cr) determination. The results showed the effectiveness of this method towards degradation and also mineralisation of DCF. For an initial concentration of 50 mg/l DCF, an applied current density of 200 A/m2, 120 min electrolysis and UV irradiation, and Z-TiO2-Ag photocatalyst, the recorded removal efficiency of COD-Cr was 57.86%.