LAUSR

Abstract Pharmaceutical compounds are one the main pollutant of the environment. In the present study, photocatalytic processes using zirconium dioxide (ZrO2) and tungsten trioxide (WO3) nanoparticles have been investigated for the feasibility of dexamethasone (DXM) decomposition. The effects of different variables such as solution pH, catalyst dosage, DXM concentration, contact time, and different irradiation sources were investigated. The results showed that the maximum efficiency achieved at pH 3 for both catalyst. Optimum catalyst dosage for WO3 and ZrO2 was 500 and 1500 mg/l, respectively. Maximum degradation was obtained at DXM concentration of 5 mg/l. The investigation of different irradiation sources exhibited that BLB/WO3 process was capable of 100% removal of DXM. Furthermore, approximately of 50% of mineralization of DXM was achieved by Halogen/WO3 in synthetic solutions. The degree of DXM mineralization and process performance in the actual hospital wastewater were also studied which showed lower efficiency than synthetic solution. Moreover, the experimental kinetics data were analyzed using Pseudo-first-order and Pseudo-second-order reactions. The obtained results followed Pseudo-first-order with the highest R2 value of 0.99 for UV/TiO2. In the actual hospital wastewater, DXM was completely decomposed using halogen/WO3 at a contact time of 100 min.