几种金属氧化物催化臭氧氧化降解p-CBA

Degradation of p-CBA by catalytic ozonation with several metal oxides as catalysts

选择Al2O3,TiO2,MnO2,Fe3O44种金属氧化物对溶液中的对氯苯甲酸(p-CBA)进行催化臭氧氧化降解。催化剂的表征结果显示:TiO2具有最大的比表面积,为93.84 m^2/g,Al2O3的比表面积最低,仅为10.28 m^2/g;MnO2和Fe3O4表面含有大量强酸性位,故其等电点较低,分别为1.45和1.82。4种催化剂对p-CBA的吸附能力与其比表面积相关,而催化臭氧氧化活性高低却与其等电点的高低顺序一致。Al2O3具有最高的等电点(6.92),也表现出相对较强的催化臭氧氧化活性。在臭氧通量6 mg/min、p-CBA初始质量浓度40 mg/L、Al2O3投加量0.5 g/L、反应时间40 min的条件下,p-CBA去除率达到58.6%,远高于单独臭氧化和吸附过程的去除率。

Several kinds of metal oxides such as Al2O3,TiO2,MnO2 and Fe3O4 were selected for the catalytic ozonation process to degrade p-chlorobenzoic acid(p-CBA)in aqueous solution.Characterization results of the catalyst show that:TiO2 has the largest specific surface area of 93.84 m^2/g,Al2O3 has the lowest specific surface area of 10.28 m^2/g;There are a large number of strong acid sites on the surface of MnO2 and Fe3O4,leading to their low isoelectric point of 1.45 and 1.82,respectively.The adsorption capability of the four catalysts to p-CBA is related to the specific surface area,while their catalytic activity for ozonation process is consistent with the order of their isoelectric points.Al2O3 has the highest isoelectric point(6.92)and exhibits relatively strong catalytic activity for ozonation.Under the conditions of ozone flux 6 mg/min,p-CBA initial mass concentration 40 mg/L,Al2O3 amount 0.5 g/L and reaction time 40 min,the removal rate of p-CBA reached 58.6%,which is much higher than that by single ozonation and adsorption.