本文選題：磺酰脲除草劑 + 飲用水處理��； 參考：《南京農(nóng)業(yè)大學》2014年碩士論文

【摘要】：磺酰脲除草劑可以有效除去雜草,因其具有高效低量、施藥時間范圍寬等特點在世界范圍內(nèi)得到廣泛應用。但這類除草劑不易揮發(fā)、不易光解且選擇性強,對不同作物的敏感性差異很大,會毒害后茬作物。進入環(huán)境中的磺酰脲除草劑會通過各種途徑遷移進入天然水體,如果受污染水體作為飲用水水源,這些農(nóng)藥將有可能直接暴露給人體。然而常規(guī)飲用水處理過程能否有效去除此類除草劑尚不清楚。本研究采用實驗室模擬常規(guī)飲用水處理工藝,選取氯磺隆、甲磺隆、氯嘧磺隆、氯吡嘧磺隆和氟胺磺隆5種長殘效磺酰脲除草劑作為研究對象,研究它們在4個典型的飲用水處理單元(包括混凝、活性炭吸附、氯化消毒和臭氧消毒)中的去除情況。結(jié)果發(fā)現(xiàn),只有不到10%的磺酰脲除草劑可通過混凝沉降過程去除；活性炭吸附較為有效,此單元中這些除草劑的去除率隨著活性炭投加量的增大而增大,去除率為50%-70%,但即使投加量增至20 mg·L-1時,仍不能達到完全去除；臭氧消毒對磺酰脲除草劑的去除非常有限；加氯消毒對此類除草劑的去除率最高,但也不能完全去除,此單元中不同種類除草劑的降解表現(xiàn)迥異,氯磺隆和甲磺隆更易被去除。從實際情況出發(fā),本研究還考察了飲用水處理過程(即混凝-沉淀-過濾-加氯消毒連續(xù)處理)對5種磺酰脲除草劑的去除效果。對比單獨氯化的結(jié)果發(fā)現(xiàn),該過程可以大幅提高這些農(nóng)藥的去除率。其中,對去離子水配制的樣品中的除草劑得到完全去除,但成分更加復雜的天然水樣中仍有部分除草劑殘留。當在加氯消毒前增設活性炭吸附單元,結(jié)果發(fā)現(xiàn)此措施可顯著提升天然水樣的去除率,使之達到100%去除。雖然整個飲用水處理過程可以完全去除磺酰脲除草劑,而且加氯消毒單元的去除率最高,但對這些除草劑的氯化反應進行深入研究發(fā)現(xiàn),這一過程中它們都生成了結(jié)構(gòu)穩(wěn)定的產(chǎn)物。在加氯量足夠的情況下,產(chǎn)物生成量取決于除草劑的初始濃度；而且這些產(chǎn)物也不隨加氯量和時間的增加而進一步降解；另外,通過質(zhì)譜分析證明,它們和磺酰脲分子中的雜環(huán)結(jié)構(gòu)(如三嗪結(jié)構(gòu)等)相關,可能具有生態(tài)毒性�？偠灾�,磺酰脲除草劑母體雖然可以在常規(guī)飲用水處理過程中被完全去除,但氯化過程中生成的產(chǎn)物并不能被完全降解,依舊具有危害人體的潛在風險。所以,本研究可為全面、準確評價這類農(nóng)藥的生態(tài)風險以及對人體的可能暴露水平提供依據(jù)。
[Abstract]:Sulfonylurea herbicides are widely used in the world because of their high efficiency and low quantity and wide application time. However, these herbicides are not volatile, easy to photolysis and highly selective. The sensitivity of these herbicides to different crops is very different, which will poison the next crop. Sulfonylurea herbicides that enter the environment will migrate into natural water bodies through various channels. If polluted water is used as a source of drinking water, these pesticides may be directly exposed to human body. However, it is not clear whether conventional drinking water treatment can effectively remove such herbicides. In this study, the conventional drinking water treatment process was simulated in laboratory. Five long residual sulfonylurea herbicides, chlorsulfuron, mesulfuron, chlorosulfuron, clopimuron and flurazuron, were selected as the research objects. Their removal from four typical drinking water treatment units, including coagulation, activated carbon adsorption, chlorination and ozone disinfection, was studied. The results showed that less than 10% of the sulfonylurea herbicides could be removed by coagulation and sedimentation, and the adsorption of activated carbon was more effective. The removal rate of these herbicides in this unit increased with the increase of the amount of activated carbon. The removal rate was between 50 and 70, but even when the dosage was increased to 20 mg L-1, it could not be completely removed; the removal of sulfonylurea herbicides by ozone disinfection was very limited; and chlorine disinfection had the highest removal rate of such herbicides, but it could not be completely removed. The degradation of different herbicides in this unit is very different, and chlorsulfuron and mesulfuron are more easily removed. The removal effect of five sulfonylurea herbicides by the process of drinking water treatment (i.e. coagulation-precipitation-filtration and chlorination disinfection continuous treatment) was also investigated. Compared with the results of chlorination alone, this process can significantly improve the removal rate of these pesticides. The herbicides in the samples prepared by deionized water were completely removed, but some herbicide residues were still found in the natural water samples with more complex composition. When activated carbon adsorption unit was added before chlorination, it was found that the removal rate of natural water samples could be significantly improved by this measure, and the removal rate of natural water samples could reach 100%. Although sulfonylurea herbicides can be completely removed during the whole process of drinking water treatment, and the removal rate of chlorinated disinfection units is the highest, the chlorination reaction of these herbicides has been studied in depth. In this process they all produce products of structural stability. When chlorine is sufficient, the amount of the product is determined by the initial concentration of the herbicide, and these products do not degrade further with the amount and time of chlorine added; in addition, mass spectrometry shows that, They are related to heterocyclic structures in sulfonylurea molecules (such as triazine) and may be ecotoxic. In a word, although the parent of sulfonylurea herbicides can be completely removed during the treatment of conventional drinking water, the products produced in the chlorination process can not be completely degraded, which still has the potential risk of harming the human body. Therefore, this study can provide a basis for comprehensive and accurate assessment of ecological risks of these pesticides and possible exposure to human body.
【學位授予單位】：南京農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU991.2;X592

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本文編號：1884985