Research On The Degradation Of Environmental Organic Pollutants Of Farm Chemical Herbicides

With the rapid development of modern agriculture and pesticide industry,a variety of herbicides are widely used.At the same time,a certain number and kinds of herbicides have been entered into the water which would inevitably produce pollution to the ecological environment,and do harm to nature and human beings.Degradation of Nicosulfuron,as a typical kind of herbicide,was investigated in this paper.By the method of contrast experiment and single factor experiment,influencing factors and regularity of degradation process was studied.Meanwhile,optimal reaction conditions of UV-electrochemical system were determined,the kinetic analysis of the reaction process was carried out,and the degradation pathway was deduced according to the degradation products.Main research contents are as follows:1)Degradation process of Nicosulfuron wastewater was studied by method of advanced oxidation and bio-chemical system.In advanced oxidation process,electrochemical,photochemical,UV-electrochemical system was applied to removing Nicosulfuron.Experimental results show removal rate was 63.8%,45.8% and 99.1% respectively.This indicates that advanced oxidation process of Nicosulfuron removal was effective,but the removal efficiency of UV-electrochemical system was the best.In the biochemical system,aerobic activated was applied for removal of Nicosulfuron,meanwhile,effects of temperature,reaction time and pH value were also studied in the process of Nicosulfuron degradation.Through the optimization of the reaction process,we reached the best degradation rate 83.2%.Through a comparative study of the two methods and Nicosulfuron degradation by the influence of the pH value of the larger,under acidic conditions,the degradation efficiency of higher than neutral and alkaline conditions.PH plays a major role in the degradation of Nicosulfuron.Degradation efficiency of acid was higher than that of neutral and alkaline conditions.2)Discusses the UV electrochemical degradation kinetics equation.The results show that UV-electrochemical degradation of Nicosulfuron followed first-order kinetics,and the correlation coefficient was good.3)In this paper,Nicosulfuron degradation products of aerobic activated sludge system and UV-electrochemical system was conducted under LC-MS.Nicosulfuron degradation products was M1-M7,The product of M1,M3,M4 which obtained by activated sludge system and UV-electrochemical system are consistent.