Degradation of diclofenac under irradiation of UV lamp and solar light using ZnO photo catalyst

Abstract

Diclofenac sodium (DCF) is a non-steroidal anti-inflammatory drug mainly used as an analgesic, arthritic and anti-rheumatic. This study deals with the degradation of diclofenac by photo catalytic-based advanced oxidation processes. The solar reactor system is comprised of quartz and borosilicate tubes for the absorption of the solar rays and transmission to the pollutant sample. Artificial UV lamp and solar rays have been applied to activate the ZnO catalyst, thereby generating highly oxidizing species. These species initiate the degradation process of the drug, which results in intermediates that finally dissociate into carbon dioxide and water. The degradation rate has been analyzed by composition analysis using high performance liquid chromatography. TOC and COD tests have also been conducted for degraded samples. ZnO catalyst loading was tested from 0.1 gm/L to 1 gm/L and the degradation rate showed a rising trend up to 0.250 gm/L, but further increase in loading resulted in a drop in degradation. Similarly, degradation is higher in acidic condition as compared to neutral or basic pH condition. The results showed a higher degradation rate for UV lamp irradiation as compared to the solar system. Moreover, TOC and COD reduction results were also found to be higher for UV lamp photo catalysis.