紫外光照射降解水中吡虫啉和啶虫脒的研究

Degradation of Imidacloprid and Acetamiprid in Aqueous Solution by Ultraviolet Irradiation

本文研究了紫外光照射技术对水模拟体系中吡虫啉和啶虫脒的降解作用,探讨了照射时间、紫外光强度、水模拟体系pH值和农药初始浓度等因素对降解效果的影响。结果表明,紫外光照射可有效降解水模拟体系中的吡虫啉和啶虫脒,且吡虫啉的降解效果优于啶虫脒。在本实验研究条件下,照射时间越长,紫外光强度越大,吡虫啉和啶虫脒的降解率越高;农药初始浓度越低,在相同照射时间下,吡虫啉和啶虫脒的降解率越高;中性和碱性的水模拟体系更利于啶虫脒的降解。采用紫外光强度为650μW/cm2的短波紫外光照射水体系30 min(pH 6,吡虫啉和啶虫脒初始浓度均为0.2μg/mL),吡虫啉和啶虫脒的降解率达到最大,分别为100%和46.30%。动力学研究表明,水模拟体系中吡虫啉和啶虫脒紫外光降解过程符合一级动力学模型(R2≥0.95)。

The effects of irradiation time,UV light intensity,pH of aqueous solution and initial concentration of imidacloprid and acetamiprid on both pesticides were studied.Results indicated that UV irradiation was effective in the degradation of imidacloprid and acetamiprid,while acetamiprid was more resistant to UV irradiation than imidacloprid.Furthermore,the degradation rate of both pesticides increased obviously with the increase of UV light intensity and irradiation time.The pH of the aqueous solution also showed significant influence on the degradation of acetamiprid,especially at alkaline and basic conditions.The maximum degradation rate of imidacloprid and acetamiprid were 100% and 46.30%,respectively,under 650 μW/cm2 UV light intensity for 30 min treatment with the initial concentration of 0.2 μg/mL（pH=6）.Moreover,the degradation of imidacloprid and acetamiprid in aqueous solution followed the first-order kinetics well（R2≥ 0.95）.