水中典型卤代甲烷降解影响因素研究

发布时间：2018-10-14 08:55

【摘要】：近年来饮用水消毒副产物(DBPs)因为种类多、毒性大、分布广而备受关注。DBPs产生于水厂末端的消毒过程,生成后缺乏有效的去除方法。管网作为连接水厂和用户的必经环节,其间发生的降解作用可影响DBPs的稳定性,并决定其发生、分布和毒性。然而,DBPs在管网内的环境行为目前了解较少,不同DBPs之间行为差异的原因也不明确。同时,突发性水污染事件的增加促使净水装置进入家庭,而当前家庭方式对DBPs的去除效果了解较少。因此,有必要对DBPs稳定性开展系统有序的研究。本课题通过测定三种卤代甲烷在各种管网条件下的降解行为,重点研究了三种卤代甲烷在水解、氧化、和还原过程中的稳定性;同时,考察了多种家庭方式对三种卤代甲烷的去除效果。水解实验表明:三种卤代甲烷的水解反应符合准一级反应,且为碱性水解,符合水解方程和阿伦利乌斯方程。反应速率随着温度和p H的增加而增加,水解速率的排序为:三溴甲烷三氯甲烷二碘甲烷。卤素离子对水解影响不大,不同水体中的水解速率略有差异。三氯甲烷和三溴甲烷水解产物为对应的卤素离子。氧化实验表明:在0-10 mg/L浓度范围内,余氯以及氯胺的氧化作用对三种卤代甲烷稳定性并没有比较明显的影响。还原实验表明:零价铁的还原作用可以使三卤代甲烷在酸性条件下迅速降解,在中性以及碱性条件下降解较慢;最佳投加量为8 g/L;Fe2+和腐殖酸会促进零价铁对卤代甲烷的还原作用;单独的SO32-、Fe2+、腐殖酸对卤代甲烷无明显还原作用;不同水体下的还原速率为海水超纯水自来水湖水。紫外光解实验表明:三氯甲烷则不能被UV254nm光解,三溴甲烷和二碘甲烷则在UV254nm下光解迅速且符合一级反应动力学;p H、Cl-、Br-对光解无影响;I-、NO3-可以促进光解作用;Fe3+、腐殖酸可以抑制光解;在超纯水中光解速率快于其他水体。反渗透(RO)净水器实验表明:前置三级滤芯对三种卤代甲烷的去除效果大小为:颗粒活性炭PP棉压缩活性炭;流速越低,去除率均越高;低浓度卤代甲烷去除率高于高浓度。反渗透膜对三种卤代甲烷均有着极高的去除率(99%);去除率和压力、浓度、p H均无关。所以家用净水器在正常使用情况下对于卤代甲烷的去除是有效的。去除卤代甲烷的家庭方式包括热水壶、微波炉、超声清洗机、风扇、搅拌机(如豆浆机、榨汁机)等家用电器,去除的原理主要利用的是卤代甲烷的易挥发特性,实验结果表明:温度、风速、超声、转速、微波均能促进了卤代甲烷的挥发,其影响大小为:转速超声温度风速微波。可见这些家庭方式对于应急处理饮用水中卤代甲烷是可行的。本课题尝试了多种去除卤代甲烷的方式方法,并取得的较好的实验结果,研究结果可为典型卤代甲烷在管网中的环境行为提供基础数据,并为民众应对突发性水污染时采取的措施提供参考意见。
[Abstract]:In recent years, (DBPs), a by-product of drinking water disinfection, has attracted much attention because of its variety, toxicity and wide distribution. DBPs is produced in the disinfection process at the end of water plant, and there is no effective removal method after it is produced. As a necessary link to connect water plants and users, the degradation of pipe network can affect the stability of DBPs and determine its occurrence, distribution and toxicity. However, little is known about the environmental behavior of DBPs in pipe networks, and the reasons for the differences among DBPs are not clear. At the same time, the increase of sudden water pollution events impels the water purification device to enter the home, but the current household mode has little understanding of the effect of DBPs removal. Therefore, it is necessary to carry out systematic and orderly research on the stability of DBPs. In this paper, the degradation behavior of three halogenated methane under various pipe network conditions was determined, and the stability of three halogenated methane in hydrolysis, oxidation, and reduction was studied. The removal efficiency of three halogenated methane by various household methods was investigated. The hydrolysis experiments showed that the hydrolysis of the three halogenated methane was in accordance with the quasi first order reaction and the alkaline hydrolysis, which was in accordance with the hydrolysis equation and the Arrhenius equation. The reaction rate increased with the increase of temperature and pH, and the order of hydrolysis rate was as follows: trichloromethane dichloromethane. The effect of halogen ions on hydrolysis was not significant, but the hydrolysis rate was slightly different in different water bodies. Trichloromethane and tribromomethane hydrolysates are the corresponding halogen ions. The oxidation experiments showed that the oxidation of residual chlorine and chloramine had no obvious effect on the stability of the three halogenated methane in the concentration range of 0-10 mg/L. The reduction experiments show that the reduction of zero-valent iron can rapidly degrade trihalomethane under acidic conditions and slow degradation in neutral and alkaline conditions. The optimum dosage of 8 g / L Fe _ 2 and humic acid could promote the reduction of halomethane by zero valent iron; with SO32-,Fe2 alone, humic acid had no effect on the reduction of halogenated methane; and the reduction rate under different water bodies was that of water, tap water, lake water, water and water, respectively. UV photolysis experiments showed that trichloromethane could not be photolysis by UV254nm, tribromomethane and diiodomethane could be photolysis rapidly under UV254nm and accord with first-order reaction kinetics, pHCl-Br- had no effect on photolysis, I-no _ 3- could promote photolysis, and Fe3, humic acid could inhibit photolysis. The photolysis rate in ultrapure water is faster than that in other water bodies. The experiment of reverse osmosis (RO) water purifier shows that the removal efficiency of three halogenated methane is as follows: granular activated carbon PP cotton compressed activated carbon, the lower the flow rate, the higher the removal rate, and the higher the removal rate of low concentration halogenated methane is higher than that of high concentration. The reverse osmosis membrane has a very high removal rate (99%) of three halogenated methane, and the removal rate is independent of pressure and concentration of, p H. Therefore, household water purifiers in normal use for halogenated methane removal is effective. Household appliances used to remove halogenated methane include hot kettle, microwave oven, ultrasonic cleaning machine, fan, mixer (such as soy milk machine, juicer) and other household appliances. The principle of removal is mainly based on the volatile characteristics of halogenated methane. The experimental results show that temperature, wind speed, ultrasonic speed, rotational speed and microwave can all promote the volatilization of halogenated methane. This shows that these household methods are feasible for emergency treatment of halogenated methane in drinking water. In this paper, several methods of removing halogenated methane have been tried, and good experimental results have been obtained. The results can provide basic data for the environmental behavior of typical halogenated methane in the pipe network. It also provides the reference for the people to deal with the sudden water pollution.
【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】：2014
【分类号】：TU991.2

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