【作者】 徐冰冰；

【导师】 陈忠林；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2008， 博士

【摘要】 饮用水安全问题一直是国际研究的热点。目前人们正面临着确保饮用水水质安全的新考验——亚硝胺污染问题。亚硝胺是当前令人关注的一类具有强致癌性的化学物质,已发现近300种亚硝胺中80-90%具有致癌作用。美国加利福尼亚火箭引擎试验基地附近饮用水井中检测出高达400000 ng·L^-1的亚硝基二甲胺后,引发了人们对饮用水中亚硝胺污染的关注。此后,人们在氯及氯胺消毒后的饮用水及污水中也都检测到典型亚硝胺有机污染物的存在。亚硝胺污染物已经成为继卤代消毒副产物之后备受关注的饮用水新型消毒副产物。如何有效地去除水中亚硝胺污染,降低其再生成的可能性,是进一步提高饮用水水质、降低饮用水安全风险的根本保障。本文在建立水中典型亚硝胺污染物检测方法的基础上,采用紫外光辐射技术降解水中存在的典型亚硝胺污染物——亚硝基二甲胺（NDMA）、亚硝基二乙胺（NDEA）、亚硝基吡咯烷（NPyr）和亚硝基哌啶（NPip）。考察相关影响因素对紫外光降解典型亚硝胺污染物效能的影响,分析确定紫外光降解亚硝胺污染物的降解产物,并由此推测出紫外光降解水中亚硝胺污染物的反应途径。通过深刻理解紫外光降解水中亚硝胺污染物的规律,寻找去除水中亚硝胺污染物高效、可行的深度处理技术。首先,建立了水中典型亚硝胺的高效液相色谱分析方法。该方法能够快速测定水中存在的五种典型亚硝胺污染物,方法具有较好的线性关系、精密度和准确度相对标准偏差（RSD）均小于2%,水样加标回收率为85.2%～108%。以二烷基亚硝胺NDMA和NDEA作为直链亚硝胺的代表,考察紫外光降解直链亚硝胺的降解规律。实验结果表明,紫外光降解能够有效地去除水中存在的NDMA和NDEA。与NDMA相比,直链结构较长的NDEA更容易被紫外光降解。低溶液pH值有利于紫外光降解水中直链亚硝胺。紫外光降解水中存在的NDMA和NDEA都能够生成各自的前质二级胺、亚硝酸盐和硝酸盐。紫外光对水中直链亚硝胺降解是由于紫外光辐射使N-N键发生断裂所致。对环状环状亚硝胺NPyr和NPip紫外光降解的实验结果表明,紫外光降解能够有效地去除水中存在的NPyr和NPip。与NPyr相比,结构较为复杂的NPip更容易被紫外光降解。溶液pH值对紫外光降解NPyr的影响作用十分微弱,而对紫外光降解NPip的影响作用较大。紫外光降解水中NPyr和NPip的降解机理基本相同,均是由于紫外光辐射使N-N键发生断裂所致。作为主要紫外光降解亚硝胺的产物,脂肪胺、亚硝酸盐和硝酸盐均是亚硝胺形成的主要前质,一旦条件适宜,脂肪胺产物很可能再次生成具有强致癌性的亚硝胺。本文采用UV-O₃高级氧化技术降解水中存在的NDMA和NDEA。实验结果表明,UV-O₃不仅能够有效地去除水中存在的NDMA和NDEA,加快降解反应速率,同时还能有效控制脂肪胺和亚硝酸盐的生成,减小NDMA和NDEA再生成的可能性。最后,以NDMA为目标污染物,考察UV-O₃高级氧化技术对NDMA再生成的控制。实验结果表明,UV-O₃在降解NDMA的同时可以有效地控制二甲胺的生成量,显著降低亚硝酸盐的产量,将可降低或消除NDMA再次生成的可能性。UV-O₃反应体系中,NDMA可被降解生成产物二甲胺,而二甲胺又在随后的反应中被降解,从而使得反应体系中二甲胺的生成量减少;同时,由于羟基自由基能够与NDMA发生反应生成产物甲胺,导致受NDMA紫外光辐射生成二甲胺的机会减小,从而使得反应体系中二甲胺的生成量减少。更多还原

【Abstract】 Drinking water risk issue has been an international research hotspot. At present people are facing many new drinking water risks, nitrosamine pollution is one of these new risks. Previously, the focus of nitrosamines mainly concentrated in food, daily consumer goods as well as air pollution, and other fields. Since N-nitrosodimethylamine （NDMA） had been detected up to 400000 ng·L^-1 in drinking water wells near to California rocket engine test site, it triggered the concerns of nitrosamines in drinking water. Since then, NDMA, N-nitrosopyrrolidine （NPyr）, and N-nitrosopiperidine （NPip） had been also detected in the chlorination and chloramination of drinking water and sewage. Nitrosamines has become a new concern of drinking water disinfection by-products （DBPs） after the halogenated DBPs. Nitrosamines is stable, and is not likely to bioaccumulate, biodegrade, adsorb to particulate matter, or volatilize difficult. Conventional water treatments can not deal with removal of nitrosamines effectively. In order to improve drinking water quality, it is essential to develop effective treatment methods for nitrosamines removal, and reducing the possibility of their regeneration.In this paper, UV direct photolysis of nitrosamines, such as NDMA, N-Nitrosodiethylamine （NDEA）, NPyr and NPip in aqueous was investigated. The objectives were not only to assess the removal efficiency of nitrosamines photodegradation by UV irradiation, but also to identify the products of each nitrosamine photodegradation, and deduce the degradation pathways especially. Then, the more effectual and thorough treatment for nitrosamines removal from water can be find out on the basis of these results.Firstly, the analysis method of nitrosamines in water was set up. Nitrosamines were analyzed by reverse phase high performance liquid chromatogram （HPLC） with UV detection. The method can not only detert the nitrosamines quickly, but also has good linear relationship, precision and accuracy. The relative standard deviation of the method was less than 2%, and the recovery with standard addition was 85.2%～108%.Taken the alkylation nitrosamines NDMA and NDEA as straight-chain nitrosamines representatives, the law of straight-chain nitrosamines degradation by UV irradiation was studied. The result showed that UV irradiation was an effective method for NDMA and NDEA removal from water. Compared with the NDMA, the longer straight-chain structure of NDEA makes it easy for UV degradation. Solution pH had great effects on NDMA and NDEA photodegradation by UV irradiation. Degradation of NDMA and NDEA by UV can generate their precursors, nitrite and nitrate. The mechanisms of NDMA and NDEA degradation by UV were basically the same, which were both considered as a result of N-N bond fission due to UV irradiation.Taken the NPyr and NPip as ring nitrosamines representatives, the law of ring nitrosamines degradation by UV irradiation was studied. The result showed that UV irradiation was an effective method for NPyr and NPip removal from water. Compared with the NPyr, NPip was easy for UV degradation. Solution pH did not affect the NPyr degradation by UV. However, solution pH had different effect on NPip photodegradation by UV irradiation. The mechanisms of NPyr and NPip degradation by UV were both considered as a result of N-N bond fission due to UV irradiation.As the major degradation products of nitrosamines, aliphatic amines, nitrite and nitrate are also the important precursors for nitrosamines. Once the appropriate conditions, aliphatic amines were likely to regenerate nitrosamines again. In order to eliminate NDMA contamination completely, and minish the possibility of NDMA regeneration at the same time, control of DMA formation became the key problem. In this paper, degradation of NDMA and NDEA by advanced oxidation technology UV-O₃ were carried out. The results showed that, UV-O₃ not only could degrade NDMA and NDEA effectively, accelerate the degradation rate, but also could control the formation of DMA, DEA and NO₂^- effectively, reduce the the possibility of regeneration. Hydroxyl radicals grnerated in UV-O₃ system due to the introduction of ozone, which resulted in increasing the rate of NDMA and NDEA degradation. In UV-O₃ process, not only UV irradiation takes part in the degradation of nitrosamines, but also the hydroxyl radicals were involved in the degradation of pollutants. Therefore, UV-O₃ advanced oxidation technology was more capacity to the degradation of organic matter.Finally, the control of NDMA regeneration by UV-O₃ advanced oxidation technology was investigated. The results showed that UV-O₃ could degrade NDMA effectively, and control the formation of the DMA, resulting in reducing or avoiding the possibility of NDMA regeneration. As UV, ozone and the hydroxyl radicals in UV-O₃ process, the mechanism of controlling on DMA formation became very complicated. On one hand, after being produced from NDMA, DMA was degraded by ozone or hydroxyl radicals. On the other hand, the mechanism of NDMA degradation was changed by introducing ozone into UV process. Reaction of NDMA and hydroxyl radical produced MA resulted in reducing the yields of DMA.更多还原