拟除虫菊酯类农药的降解研究

发布时间：2018-04-29 00:18

  本文选题：拟除虫菊酯 + 功夫菊酯　； 参考：《广西大学》2017年硕士论文

【摘要】：拟除虫菊酯类农药作为一种广谱、高效、低毒的杀虫剂而被广泛应用,大量的使用导致环境污染、生态破坏及危害人类健康等问题。如何有效去除环境中的这些农药已成为人们广泛关注的问题。本论文从光降解和微生物降解两方面研究了拟除虫菊酯类农药的降解行为,主要结果如下:1.对功夫菊酯和溴氰菊酯水溶液在不同光源下的降解进行了研究。结果表明,紫外光照射下的降解速率远远快于模拟太阳光照射,其降解速率分别加快了 50.97倍和54.51倍。同时在两种光照下的光降解过程符合一级动力学规律。2.应用纳米二氧化钛(nTiO2)作为光催化剂对功夫菊酯和溴氰菊酯水溶液进行模拟太阳光催化研究。结果表明,nTiO2起到了催化降解的作用,与不加nTiO2相比,降解速率分别加快了 12.22倍和8.48倍,且降解行为符合一级动力学规律。3.优化了模拟太阳光条件下催化剂的用量。结果表明,降解速率随着催化剂的量的增加先加快后减慢。对于功夫菊酯和溴氰菊酯水溶液,其最佳用量分别为 2.0 mg/L nTi02 和 0.8 mg/L nTi02。4.联合超高效液相色谱-质谱/质谱(UPLC-MS/MS)和气相色谱-质谱(GC-MS)对功夫菊酯和溴氰菊酯降解的产物进行了鉴定,同时推断其可能的降解路径。功夫菊酯的降解主要有酯键断裂,C-C键断裂,C-O键断裂,光氧化,光异构化,脱氰基,脱羟基等过程,其降解产物主要有间苯氧基苯甲醛、间苯氧基苯乙腈、α-氰基-3-苯氧基苄醇等。溴氰菊酯在水溶液中的光降解主要有酯键断裂,C-C键断裂,C-O键断裂,光氧化,脱氰基,脱羟基,重排等过程,其降解产物主要有间苯氧基苯甲醛、间苯氧基苯乙腈、间苯氧基苯甲酸甲酯等。5.从菊酯类农药生产厂的生化处理池的活性污泥中分离筛选到两株对功夫菊酯有较高降解能力的菌株A4和G3,分别能以功夫菊酯为唯一碳源和氮源生存。对筛选出来的菌株进行菌落形态观察和ITS序列测定,并构建系统邻近发育树,最终将其分别鉴定为棘孢曲霉(Aspergillusaculeatus)和草酸青霉(PeniPillium oxalicum)。6.采用高效液相色谱(HPLC)研究了初始浓度、接种量、pH、温度等对A4和G3菌株降解特性的影响。结果表明,菌株A4和G3对不同初始浓度的功夫菊酯的降解行为符合一级动力学规律;A4菌株在接菌量为0.015 g/L、pH为7.0、温度为28℃条件下降解效果最佳;G3菌株在接菌量为0.010g/L、pH为7.0、温度为28℃条件下降解效果最佳。
[Abstract]:Pyrethroid pesticides are widely used as a kind of broad spectrum, high efficiency and low toxicity insecticides, which lead to environmental pollution, ecological destruction and harm to human health. How to effectively remove these pesticides in the environment has become a widespread concern. In this paper, the degradation behavior of pyrethroid pesticides was studied from the aspects of photodegradation and microbial degradation. The main results were as follows: 1. The degradation of kungthrin and deltamethrin aqueous solution under different light sources was studied. The results showed that the degradation rate of UV irradiation was much faster than that of simulated solar irradiation, and the degradation rate was 50.97 times and 54.51 times faster, respectively. At the same time, the photodegradation process under two kinds of light is in accordance with the first-order kinetic law. Nanocrystalline TIO _ 2 (TIO _ 2) was used as photocatalyst to simulate the photocatalysis of kungthrin and deltamethrin in aqueous solution. The results showed that the degradation rate of NTiO2 was 12.22 times and 8.48 times faster than that without nTiO2, and the degradation behavior was in accordance with the first-order kinetic law .3. The amount of catalyst under simulated sunlight was optimized. The results showed that the degradation rate increased firstly and then slowed down with the increase of the amount of catalyst. For the aqueous solution of cypermethrin and deltamethrin, the optimum dosage is 2.0 mg/L nTi02 and 0.8 mg/L nTi02.4, respectively. The degradation products of krysanthemum and deltamethrin were identified by UPLC-MS / MS and GC-MSMS, and the possible degradation pathways were deduced. The degradation of kungthrin mainly includes ester bond breakage, C-C bond cleavage, photooxidation, photoisomerization, cyanide removal, dehydroxylation and so on. The main degradation products are m-phenoxy benzaldehyde, m-phenoxyphenyl acetonitrile, 伪 -cyano-3-phenoxy benzyl alcohol and so on. The photodegradation of deltamethrin in aqueous solution mainly includes ester bond breakage, C-C bond breaking, photooxidation, cyanide removal, dehydroxylation, rearrangement and so on. The main degradation products of deltamethrin are m-phenoxy benzaldehyde, m-phenoxybenzonitrile, and so on. Methyl m-Phenoxy benzoate, et al. Two strains A4 and G3 with high biodegradation ability were isolated from the activated sludge of biochemistry treatment pond in the production plant of pyrethroid pesticides. The strains A4 and G3 were found to be the only carbon source and nitrogen source respectively. Colony morphology and ITS sequence were observed and phylogenetic tree was constructed. The strains were identified as Aspergillus aculeatus and PeniPillium oxalicum.6respectively. The effects of initial concentration, inoculum pH and temperature on the degradation characteristics of A4 and G3 strains were studied by high performance liquid chromatography (HPLC). The results show that The degradation behavior of different initial concentrations of krysanthemum by strain A4 and G3 is in accordance with the first-order kinetic rule: the inoculation amount of A4 strain is 0.015 g / L ~ (-1) pH is 7.0, and the temperature is 28 鈩，

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