论文部分内容阅读
利用光催化技术探讨了烟碱类杀虫剂噻虫胺在水体环境中降解的可行性,不同催化剂浓度、反应温度、底物浓度、溶液初始p H值和不同阴阳离子等因素对其光催化降解动力学的影响,及其初步的光催化降解机制.结果表明噻虫胺的光催化降解符合L-H动力模型,其降解假一级动力学速率常数为0.050 6 min-1.当催化剂用量(TiO_2)为3.0 g·L~(-1)时,噻虫胺的光催化降解速率最大;高温和较低的底物浓度有利于噻虫胺的光催化降解;溶液的初始p H值为5时噻虫胺的降解速率最大,强酸和强碱均不利于其光催化降解.而无机阴、阳离子对噻虫胺降解均有明显的抑制作用.最后,通过GC/MS对噻虫胺光催化降解中间产物进行了初步鉴定,研究发现在活性氧物种的作用下噻虫胺降解途径主要有母体化合物的羟基化,硝基胍基团中N—N的断裂,以及连接硝基胍和噻唑环的C—N键的裂解等.
The photocatalytic technology was used to investigate the feasibility of the degradation of clothianidin, a nicotine insecticide, in water environment. The effects of different catalyst concentrations, reaction temperature, substrate concentration, initial p H value and different anions and cations on the photocatalytic activity The results showed that the photocatalytic degradation of clothianidin was in accordance with the LH kinetic model and its pseudo first-order kinetic rate constant was 0.050 6 min-1. When the amount of catalyst (TiO 2 ) Was 3.0 g · L ~ (-1), the photocatalytic degradation rate of clothianidin was the highest. High temperature and low substrate concentration were favorable for the photocatalytic degradation of clothianidin. The initial p H value of the solution was 5 Clothianidin had the highest degradation rate, strong acid and strong base were not conducive to its photocatalytic degradation, while inorganic anion and cation had a significant inhibitory effect on clothianidin degradation.Finally, the photocatalytic degradation of clothianidin by GC / MS Intermediate products were initially identified, the study found that the role of reactive oxygen species of clothianidin degradation mainly hydroxylation of the parent compound, nitroguanidine group N-N cleavage, and the connection nitroguanidine and thiazole ring C-N cleavage and so on.