Removal of diclofenac from aqueous media by UV/TiO2 process in a fixed-bed batch photoreactor: Optimization by response surface methodology

In this study, the removal of a pharmaceutical contaminant, diclofenac (DCF), using the UV/TiO₂ process in a fixed-bed batch photoreactor was investigated. The effective operating conditions influencing the process efficiency were optimized using Response Surface Methodology (RSM) of the Central Composite Design (CCD) type. The results of the experimental design indicated a positive effect of light irradiation time and volumetric flow rate, and a negative effect of initial DCF concentration and pH on the removal efficiency of DCF from aqueous media. Among the studied parameters, irradiation time and pH were found to be the most influential. The optimal pH for DCF removal in this process was approximately 4.5.