La2O3和CeO2的制备及催化臭氧氧化对氯硝基苯

为提高单独臭氧氧化去除水中有机污染的能力,分别以La(NO3)3.6H2O和Ce(NO3)3.6H2O为前驱体,采用水解沉淀法制备La2O3和CeO2粉体,利用X射线衍射、N2吸附、扫描电镜以及红外光谱分析技术对样品的晶相结构、粒径大小、比表面积、孔容、孔径分布以及表面官能团等进行表征.以蒸馏水配制的对氯硝基苯溶液(pCNB)为目标物,考察La2O3和CeO2的催化臭氧氧化活性.结果表明,La2O3和CeO2对pCNB的吸附作用有限,20 min的吸附率分别为6.7%和9.9%.臭氧对pCNB的去除能力有限,反应20 min的去除率仅为37.2%,以La2O3为催化剂时,去除效果有明显增加,反应20 min时去除率为82.1%,而以CeO2为催化剂时,去除效果反而没有O3单独氧化效果好,20 min时的去除率仅为24.3%.

Synthesis of lanthanum oxide and cerium oxide and ozonation catalytic activities of p-chloronitrobenzene

To improve the efficiency of ozonation for removal of organic pollution from water,lanthanum oxide and cerium oxide were prepared as catalysts for the catalytic ozonation by hydrolysis of La(NO3)3·6H2O and Ce(NO3)3·6H2O,respectively.The physicochemical features including crystallite phases,crystallite size,BET surface area,total pore volume and functional groups of the catalysts were characterized by XRD,N2adsorption,SEM and FTIR spectrum analysis.The ozonation catalytic activities of lanthanum oxide and cerium oxide were tested by catalytic ozonation of trace p-chloronitrobenzene(pCNB) in water.The results showed that the adsorption rates of pCNB by lanthanum oxide and cerium oxide in 20 min were 6.7% and 9.9%,respectively.The removal rate of pCNB by ozone alone in the reaction for 20 min was only 37.2%.The removal rate of pCNB was significantly increased by adding lanthanum oxide as the catalyst,and the pCNB removal rate of 82.1% was obtained after the reaction for 20 min,while the pCNB removal of 24.3% was obtained after the reaction for 20 min by using cerium oxide as the catalyst.