Photolysis characteristics of oxathiapiprolin in aqueous solution
[Aims]This study aims to explore the photolysis characteristics of oxathiapiprolin in water,and provide reliable basis for the rational use and environmental safety evaluation of this pesticide.[Methods]High performance liquid chromatography was used to investigate the photodegradation kinetics of oxathiapiprolin.The effects of light source,pH,initial concentration,humic acid,and TiO2 on the photolysis of oxathiapiprolin in water were studied.[Results]Under the irradiation of a 500 W mercury lamp,a 20 W mercury lamp or a 500 W xenon lamp,the half-lives of oxathiapiprolin were 2.7 min,18.1 min or 770.2 h,respectively;using a 20 W mercury lamp as the light source,the order of the effect of buffer solution pH on the photolysis rate of oxathiapiprolin was pH 4＞pH 9＞pH 7.There was no significant difference in degradation rate when the initial mass concentration of oxathiapiprolin was 1 and 5 mg/L,but as the concentration of oxathiapiprolin increased to 10 mg/L,the degradation rate decreased;the higher the concentration of humic acid added,the stronger the inhibitory effect on the photodegradation of oxathiapiprolin.When the mass concentration of TiO2 was 1 mg/L,it had a promoting effect on the photolysis of oxathiapiprolin.When the mass concentration of TiO2 increased to 5,10 or 80 mg/L,it had an inhibitory effect on the photolysis of oxathiapiprolin.[Conclusions]With a 20 W mercury lamp as the light source,the photolysis half-life of oxathiapiprolin under different conditions is less than 3 h.Oxathiapiprolin belongs to the category of easily photolytic pesticides.Acidic and alkaline solutions can promote the photolysis of oxathiapiprolin;the light source and initial concentration are important factors that affect the degradation of oxathiapiprolin;there is a negative correlation between the concentrations of humic acid and the photolysis rate of oxathiapiprolin;TiO2 at low concentrations promote the degradation of oxathiapiprolin,while TiO2 at high concentrations inhibit its degradation.
NETL
NSTL
万方数据
