Screening of Homogeneous CWAO Catalysts for Treatment of Ceramic Printing Waste-Water

The ceramic printing and dyeing waste-water was treated by catalytic wet oxidation. The catalytic oxidation reaction was carried out under the conditions of 50 mg/L metal ion concentration, 180 °C of reaction temperature, 2.5 MPa of oxygen partial pressure and 500 rpm of stirring speed, and the time of catalytic oxidation was set at 90 min. Comparing the effect of structural auxiliaries and blank group on COD removal rate of effluent, the structural auxiliaries have no effect on effluent, that is, no catalytic effect; Comparing the blank group without adding catalyst, the copper nitrate has the highest cod removal rate of 72.5% for waste-water, so it can be used as the best homogeneous catalyst to treat waste-water. The order of catalytic effect from high to low is: Cu(NO3)2 > CuSO4 > Fe(NO3)3 > Fe2(SO4)3 > Co(NO3)2 > Cr(NO3)3 > Ni(NO3)2 > AgNO3 > Zr(NO3)4. Among the nine types of homogeneous catalysts, the most effective Cu(NO3)2*H2O catalyst treated the ceramic printing and dyeing waste-water, the COD decreased from 3775 mg/L to 1038 mg/L and the COD removal rate reached 72.5%, when the catalyst was not added under the same operating conditions. The COD removal rate of water samples was increased by 32.9%.