Photocatalytic Treatment of Spent Caustic Wastewater Color

Document Type : Original Article


1 Faculty of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan, Iran

2 Chemical Engineering Department, Amirkabir University of Technology, Tehran, Iran

3 Department of Chemical and Biomolecular Engineering,Rice University,Texas,USA


TiO2/Fe3O4 and TiO2/Fe2O3 nano-composites with various ratios were synthesized by an ultrasonic-assisted deposition-precipitation method and their UV-light for treatment of spent caustic wastewater color was investigated. The effect of Fe3O4/TiO2 and Fe2O3-TiO2 nano-composites ratio on the photocatalytic activity and magnetic property of the nano-composites was studied by comparing their decolourization curves and magnetism in the presence of magnet, respectively. The results revealed that the decolourization efficiency of 1 wt% Fe3O4/TiO2 nano-composite reached about 43% within 60 min UV irradiation at room temperature. However, this sample showed the least magnetism. Also, the ability of synthesized nano-composites in holding the adsorbed spent caustic wastewater color on their surface and the effect of pH were investigated. The photo degradation of spent caustic wastewater was studied at five different pH values (2, 4, 6, 8, and 10) and pH 4 shows the highest photocatalytic efficiency of 91%.