Co-MTiO_2对几种有机磷农药的光催化降解效果

Photocatalytic Degradation of Several Organophosphorus Pesticides over Co-MTiO_2

为了制备能光催化降解有机磷农药的高效、稳定催化剂,以钛酸异丙酯为钛源,表面活性剂十二烷基胺为模板剂,采用水热合成法,通过直接嵌入的方式制备了Co掺杂的锐钛矿型纳米介孔二氧化钛(Co-MTiO2),在500W高压汞灯的照射下催化降解乙酰甲胺磷、氧化乐果、敌百虫和敌敌畏4种有机磷农药。结果表明:Co-MTiO2为热稳定性和比表面积高的纯锐钛矿晶型的介孔二氧化钛材料,金属Co离子已经完全掺杂到TiO2的骨架和表面上,没有检测到氧化钴和钴钛酸;光照时间、催化剂用量、农药初始浓度、体系pH值对光催化降解效率有很大的影响,随光照时间和催化剂用量的增加,4种有机磷农药的光降解效率均逐渐增大,催化剂的添加量为0.2g/L、农药的初始浓度为20mg/L时光降解效率最大,pH的影响较为复杂。催化剂具有很好的光催化活性和稳定性,重复使用3次光催化活性仅有微小的改变。

In order to prepare more efficient and stable catalysts which could be employed to efficiently catalytic degradation of organophosphorus pesticides in light conditions,Cobalt-doped mesoporous titania（Co-MTiO2） with anatase crystalline structural wall was prepared by direct incorporation pathway using 1-dodecylamine as structure-directing agent and titanium tetraisopropoxide as titania source.The structures of the material were characterized by nitrogen adsorption,XRD,HRTEM,FT-IR and XPS,the photo-catalytic degradation of four organophosphorus pesticides（acephate,omethoate,trichlorfon,dichlorvos） over the Co-MTiO2 were studied using high pressure mercury lamp as light resource,the effects of illumination time,catalyst dosage,original concentration,pH were discussed.The results indicated that the catalyst exhibited highly thermal stability,high specific surface area and large pore size;and there was no peaks corresponding to cobalt oxides and cobalt titanate observed.The illumination time,catalyst dosage,original concentration,pH value had great influence on the photocatalytic degradation of the organophosphorus pesticides,the photocatalytic degradation increased gradually with the increasing of illumination time and catalyst dosage,the photocatalytic degradation reached maximum when catalyst dosage was 0.2 g/L,initial concentration was 20 mg/L,the effect of pH was more complex.The repeatability of the catalyst indicated that material was a good catalyst with high photo-catalytic activity and stability,which could be reused three times with catalytic activity changed little.