Investigation of the effect of TiO2 and Fe2+ catalysts in the advanced oxidation processes in order to remove the chemical oxygen demand from textile wastewater

Abstract

In this study, the removal of chemical oxygen demand in the wastewater of the textile and dyeing plant of Jey Industrial Zone using UV/H2O2 process in the presence of titanium dioxide and iron ion (II) catalysts was investigated. The experiments were performed by an advanced oxidation process in the presence and or absence of UV light. The effect of operating variables such as time (30, 90 and 150 min), UV lamp power (0, 15 and 30W), hydrogen peroxide concentration (100, 500 and 900mg/L), and catalyst concentration (values for titanium dioxide of 100, 500 and 900mg/L and for iron ion (II) of 10, 50 and 90mg/L) at pH=3 were investigated on the reduction of chemical oxygen demand of textile wastewater. All experiments were performed in a glass reactor at a temperature of 25 °C and on a magnetic stirrer at a suitable speed, and 27 experiments (for each type of catalyst) were randomly tested using the Box-Behnken design method. The results show that in the UV/H2O2/Fe2+ process, at time of 138min, the UV lamp power of 30W, the concentration of hydrogen peroxide of 677mg/L, and the concentration of iron ion of 50mg/L, the maximum rate of removal of chemical oxygen demand was equal to 90.20%. While in the UV/H2O2/TiO2 process, the highest rate of chemical oxygen demand removal was about 100% in time of 148min, the UV lamp power of 30W, the concentration of hydrogen peroxide of 710mg/L, and the concentration of titanium dioxide of 593mg/L.