采用络合焙烧法制备了铈负载γ-Al2O3催化剂,置于电解槽中,构建电-多相催化体系,电解氧化处理腐植酸模拟废水。以COD值为考察指标,考察了络合硝酸铈和草酸的浓度及比例、络合pH值、焙烧温度对催化剂电催化活性的影响;其催化活性和重复稳定性与浸渍焙烧法催化剂进行比较,并通过SEM,XRD进行表征。结果表明:在硝酸铈和草酸的物质的量之比为1.5∶1,硝酸铈浓度0.06 mol.L-1,pH为3,焙烧温度823 K的条件下,制得的负载型催化剂催化效果达到最佳。用于电解处理腐植酸废水45 min,COD去除率可达到50%,在相同条件下比空白样的COD去除率提高了17%,在重复使用6次后仍具有较好的催化效果,虽然活性略低于浸渍法,但其稳定性明显高于浸渍法。
The Ce/γ-Al2O3 catalysts were prepared by an complexation-calcination method.The rare earth heterogeneous catalytic oxidation system was built by embedding the catalysts in electrolytic cell to electrolyze and oxidate humic acid.The effects of calcination temperature,the concentration of Ce(NO3)3,pH value and the ratio of Ce(NO3)3 to H2C2O4 on the activity of the catalysts and the comparison with the impregnated one in electro-catalytic activity and stability were studied.Meanwhile,their effectiveness in removing the organic compounds in humic acid was evaluated by measuring COD.The catalysts were characterized by XRD and SEM.The optimum conditions for the preparation of Ce /γ-Al2O3 catalysts were calcination at 823 K,0.06 mol·L-1 concentration of Ce(NO3)3,pH of 3 and 1.5 ratio of Ce(NO3)3 to H2C2O4,the removal rate of COD could reach 50% which was 17% higher than control sample after electrolyzation by Ce/γ-Al2O3 catalysts for 45 min.Compared to the impregnated one,complexation catalysts possessed better stability,even repeated use for 6 times,it also had good catalytic effect,but little poorer electro-catalytic activity than the impregnated one.