TiO_2对几种农药在土壤中光降解的催化作用

Effect of TiO_2 on photodegradation of several pesticides in surface soil

以太阳光为光源,研究了TiO2添加量、土壤厚度对毒死蜱、苯线磷、克百威、多菌灵在土壤中光催化降解的影响,并分析了毒死蜱、苯线磷初始浓度对其光催化降解的影响。结果表明,这4种农药的光降解均符合准一级动力学方程,随着TiO2添加量从0mg/kg增加到200mg/kg,光催化降解一级动力学常数逐渐增加。这4种农药在不同厚度含有TiO2的土壤中的光催化降解率不同;在土壤厚度较大的情况下,相应的半衰期也较长;在土壤中添加毒死蜱、苯线磷浓度相对较低的情况下,其对应的光催化降解较快。

Photolysis of 4 pesticides （chlorpyrifos, fenamiphos, carbonfuran and carbendazim） with TiO2 as catalyst under sunlight illumination was investigated to determine the effect of TiO2 dosage, thickness of the surface soil and initial concentration of pesticides on photodegradation efficiency. The results showed that photodegradation of several pesticides fitted the quasi first-order kinetic equation, the constant of photolysis kinetics increased with increasing the TiO2 dosage from 0 to 200 mg/kg. Thickness of the surface soil played an important role on pesticides photolysis, the pesticides in deep soil had a relative long half-life and slow photolysis rate. The degradation rate of chlorpyrifos and fenamiphos increased with decreasing their initial concentration.