Treatment of real artificial leather manufacturing wastewater containing Dimethylamine (DMA) by photocatalytic method

In this research, the treatment of real artificial leather manufacturing wastewater by two commercial photocatalysts as a branch of advanced oxidation processes has been investigated. A batch slurry reactor was employed in the presence of two types of catalysts, namely TiO2 and ZnO, along with UV irradiation. The experiments were performed on Box–Behnken design method considering the three effective parameters such as pH, the concentration of catalyst, and hydrogen peroxide as a co-oxidant. Results showed that the most important parameter in chemical oxygen demand (COD) reduction was pH. Additionally, some other parameters, such as the interaction between pH and co-oxidant as well as catalyst and co-oxidant concentration, are effective. At optimum condition [pHint = 3, catalyst concentration = 0.7 g/l and H2O2/COD = 4.00 (H2O2 concentration = 10 g/l)], the predicted and actual COD reduction was 52.54 and 56.87%, respectively, representing a good agreement between posed model and performed experiments. According to pH changes during the process and its influence on the removal of COD, more experiments were done by fixing pH at constant level, and the COD reduction reached 92.66% at 9 h. The kinetic studies in terms of COD removal showed that the reaction followed the first-order model.