紫外辅助化学法降解二氯苯酚和十溴联苯醚的研究

发布时间：2018-03-31 04:03

本文选题：二氯苯酚　切入点：十溴联苯醚　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：卤代有机物化学性质稳定,容易在生物体内蓄积,并且具有较强的毒性和较高的三致效应(致癌、致突变和致畸),其中有很大一部分被列为环境优先控制的污染物。本研究以二氯苯酚(DCP)和十溴联苯醚(BDE-209)作为代表,对其进行紫外辅助化学法的降解研究。DCP是我国自然水体中主要的污染物之一,BDE-209是应用广泛的阻燃剂,二者都可以对环境和人类健康造成严重危害。本实验使用的紫外辅助化学法分为紫外催化湿式氧化法和紫外高级还原法两种。通过单因素实验优化最佳降解条件,并在最优条件下,进行脱卤离子和中间产物的检测,推测其降解机理。采用紫外催化湿式氧化法对DCP进行降解。研究表明,此方法对DCP降解效果显著,对于浓度为50 mg/L的DCP溶液,在pH值为3,H_2O_2投加浓度为50μmol/L,CuSO_4的投加浓度为1 g/L,紫外光强度为3.5 W/m2的条件下,反应40 min后,对DCP的去除率可达88.74%,在此条件下进行TOC和氯离子的测定,发现TOC去除率为69.9%,脱氯率为81.84%。说明此方法不仅有脱氯作用,还可将DCP开环矿化为CO2和H2O等。使用紫外高级还原法对DCP进行降解研究,选取Na_2SO_3和NaBH_4作为还原剂,发现NaBH_4的作用略强于Na_2SO_3,对于浓度为50 mg/L的DCP溶液,在pH值为12,NaBH_4的投加量为2 mmol/L,紫外光强度为3.5 W/m2的条件下,反应60 min后DCP去除率为83.79%。对其TOC和氯离子进行测定,发现此方法对DCP的降解主要以脱氯为主,脱氯率为50.32%,TOC去除率仅为8.6%。在证明了紫外高级还原法显著的作用后,选取更难降解的BDE-209作为目标物,同样选取Na_2SO_3和NaBH_4作为还原剂,发现NaBH_4的作用略强于Na_2SO_3,对于浓度为40 mg/L的BDE-209溶液,在pH值为12,NaBH_4的投加量为2 mmol/L,紫外光强度为3.5 W/m2的条件下,反应60 min后BDE-209去除率为89.25%。使用GC-MS对中间产物进行检测,发现其降解以脱溴为主,其中九溴、八溴联苯醚是主要的中间产物,本反应降解BDE-209主要以脱溴为主,而且会逐个脱掉溴原子。
[Abstract]:Halogenated organic compounds have stable chemical properties, easy to accumulate in organisms, and have strong toxicity and high triple-effect (carcinogenesis, carcinogenesis). Mutagenicity and teratogenicity, a large proportion of which are listed as environmentally priority control pollutants. In this study, dichlorophenol (DCP) and decabromodiphenyl ether (BDE-209) were used as examples. Degradation of BDE-209 by UV assisted chemical method. DCP is one of the main pollutants in natural water in China. BDE-209 is a widely used flame retardant. Both of them can cause serious harm to the environment and human health. The ultraviolet auxiliary chemical method used in this experiment is divided into two kinds: ultraviolet catalytic wet air oxidation method and ultraviolet advanced reduction method. The optimum degradation conditions are optimized by single factor experiment. Under the optimum conditions, the dehalogenation ions and intermediate products were detected, and the degradation mechanism was speculated. UV catalytic wet air oxidation method was used to degrade DCP. The results showed that the degradation effect of this method on DCP was remarkable. For DCP solution with 50 mg/L concentration, under the conditions of 50 渭 mol / L CUSO _ 4 and 50 渭 mol / L CUSO _ 4, the removal rate of DCP can reach 88.74% after 40 min reaction. Under these conditions, TOC and chloride ions are determined. The results show that the removal rate of TOC and dechlorination are 69.9 and 81.84 respectively. It shows that this method can not only dechlorinate, but also mineralize DCP into CO2 and H2O. The degradation of DCP is studied by ultraviolet advanced reduction method, and Na_2SO_3 and NaBH_4 are selected as reductants. It was found that the effect of NaBH_4 was slightly stronger than that of NaBH_4. For 50 mg/L DCP solution, the removal rate of DCP after 60 min reaction was 83.79 when the dosage of DCP was 2 mmol / L at pH 12 mg/L NaBHH4, and the UV intensity was 3.5 W/m2. It was found that the degradation of DCP by this method was mainly dechlorination, and the dechlorination efficiency was only 8.6. after proving the remarkable effect of ultraviolet advanced reduction method, the more difficult BDE-209 was chosen as the target, and the Na_2SO_3 and NaBH_4 were also selected as reducing agents. It was found that the effect of NaBH_4 was slightly stronger than that of NaBH_4. For 40 mg/L BDE-209 solution, the removal rate of BDE-209 was 89.25 when the dosage of BDE-209 was 2 mmol / L at pH 12 mg/L and UV intensity was 3.5 W/m2. GC-MS was used to detect the intermediate product. It was found that the degradation of BDE-209 was mainly debromination, in which pentabromyl and octabromodiphenyl ether were the main intermediate products. In this reaction, debrominated BDE-209 was mainly debrominated, and the bromine atoms were removed one by one.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X505

【参考文献】