利用TiO2-ZnO复合纳米材料对小白菜中残留的4种常用有机磷类农药(乙酰甲胺磷、乐果、马拉硫磷、水胺硫磷)的去除效果进行了研究。结果表明,经过复合纳米材料处理的小白菜,4种有机磷农药的1 h平均去除率可以达到40%,5 h后可达80%以上。在相同的处理方法下,残留水胺硫磷的去除效果最好;小白菜中农药残留的去除率随初始浓度的增大而降低,当初始浓度从5 mg/L增大到40 mg/L时,初始浓度对乐果的残留量影响最大,其1 h去除率为原来的79%;另外还探讨了在TiO2-ZnO纳米复合材料作用下,小白菜中残留农药的光催化降解动力学过程,当农药初始浓度为5 mg/L时,反应速率常数与农药残留量的关系为ln(C0/Ct)=kt+B,为表观一级反应。

The photocatalytic degradation of organophosphorous pesticide residues in pakchoi by TiO2-ZnO complex nanomaterials was investigated in this paper.We took four organophosphorous pesticides in common use as researching object and obtained the results showing that different pesticides were removed at different rate.The average removal rate of the 4 kinds of pesticides residue was more than 40% after 1h and more than 80% after 5h.The removal effect of the isocarbophos was the best compared to the average residue removal percentage.The concentration of pesticide residues in pakchoi was higher,the degradation rate of pesticide residues in vegetable was lower.When the original concentration of the organophosphorous pesticide was 5 mg/L,the kinetic equation for photocatalytic degradation was derived as ln(C0/Ct) =kt + B,which fitted in with the first-order kinetic model.