Optimization of the Advanced Photocatalytic Oxidation Process in the Presence of NH2-MIL125(Ti) Catalysts in Wastewater Treatment of Pharmaceutical Industry

Discharge of pharmaceutical industry wastewater by organic compounds containing pharmaceutical compounds, especially antibiotics into aquatic environments is one of the environmental issues. Advanced oxidation processes such as photocatalytic process is one of the processes which has attracted attention. The aim of this study was to optimize the efficiency of the advanced photocatalytic oxidation process in the presence of NH2-MIL125(Ti) catalyst in the treatment of pharmaceutical industry effluents. In this study, NH2-MIL125(Ti) catalyst was synthesized by solvothermal method and its characteristics were investigated by SEM, EDAX, FTIR and XRD analyzes. For optimization, use of the central composite design, and the effect of pH, nanocomposite dose and reaction time variables, on the COD removal in pharmaceutical wastewater was investigated. The results of the catalyst analysis illustrated that the synthesis of catalyst was successful. Also, the proposed optimization of the model based on the correlation coefficient (R2=0.99), is quadratic. Optimal conditions of process were pH 6.9, reaction time 79 min, and nanocomposite dose equal to 0.5 g/L. At optimal conditions, 68% of the initial COD was removed. Adsorption and photolysis mechanisms are much less efficient than the photocatalytic process. In this study, the soluble COD decreased from 3100 mg/L to 992 mg/L. The effluent from this system can be discharged to the municipal wastewater collection system.