Treatability and Kinetic Analysis of BPA-containing Wastewater by Catalytic Ozone Processes Using ZnSO4 and ZnO Catalysts

Abstract

BPA (Bisphenol-A) is an organic colorless crystalline synthetic compound with the chemical formula of (CH3)-C-(C6H4-OH)(2). The chemical structure of BPA consists of two methyl functional groups which are connected by a bridge to the phenol rings. The purpose of this study is to investigate the treatability of containing BPA wastewater using by homogeneous (ZnSO4 catalyst) and heterogeneous (ZnO catalyst) catalytic ozone processes (COPs). The BPA removals of ZnO catalyst COP method and ZnSO4 catalyst COP methods were compared and using the ZnO catalyst COP process gave better results than the ZnSO4 catalyst COP process. For the BPA removals, the experimental parameters including pH, catalysts dose, ozone dose, and reaction time parameters were optimized by changing one parameter at a time. As a result of 12.5 min of ZnSO4 oxidation, 94.16% of BPA removal was achieved under the optimum conditions (pH 6.32, 1 mg/L ZnSO4 dose, 2400 mg/L O-3 dose). However, under optimum conditions (pH 6.32, 50 mg/L ZnO dose, 2400 mg/L O-3 doze, 20 min reaction time), the BPA removals have been obtained as 98.52%. The second-order kinetic model has been found to be the most suitable model for both processes and the regression coefficients (R-2) have been found as 0.999 and 0.9979 for ZnSO4 and ZnO catalysts COPs, respectively. The reaction rate constants (k) have also been calculated as 0.0939 L.mg(-1).min(-1) and 0.0509 L.mg(-1).min(-1) for BPA in homogeneous and heterogeneous COPs, respectively.