紫外光解提高有机物的可生化性

发布时间：2018-01-19 06:05

本文关键词： 苯酚 2 4 6-三氯酚吡啶生物降解紫外光解　出处：《上海师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着工业生产的快速发展,许多污染物的大量排放到自然水体,导致地表水甚至地下水受到了严重污染。其中尤其引起人们关注的是一些难以生物降解的有机污染物存在于自然水体中。对于一般的污染物,生物处理方法是人们首选的方法,因为生物处理技术的最突出优点就是经济可行,且可以易于应用于实际。但是对难降解有机废水的处理,单纯采用单一的生物方法处理时,生物处理方法有时难以体现出其优越性。因为大部分难降解有机污染物对微生物均有一定的生物抑制性,有些甚至还有生物毒性。本文以工业生产过程中常见的有机物,苯酚,2,4,6-三氯酚(TCP)和吡啶为研究对象。它们的供体特点是都是以苯环为基本结构的有机污染物。通过对这几种难降解有机污染物的研究,发现这3种污染物均为光敏性物质,在紫外光解后,它们会生成一定的中间产物,同时有机酸成为内源电子供体,可以加速难降解有机污染物的生物降解。首先对苯酚进行紫外光解,在紫外光解过程中,苯酚首先会分别形成对苯二酚和邻苯二酚,同时生成少量的有机酸。在此基础上提出了苯酚的紫外光解途径,随后对相关紫外光解中间产物的生成规律进行质量平衡计算。结果证实了苯酚的光解途径。在随后的生物降解过程中,以未经过紫外光解的样品为基准,比较了经过紫外光解之后,苯酚生物降解速率提高了39%。其次,对TCP先进行了紫外光解研究,发现TCP在紫外光解过程中,邻位(6号位)的氯离子优先脱落,生成2,4-二氯酚。随后再进一步脱氯生成4-氯酚。与此同时,6号位上加入一个羟基生成3,5-二氯邻苯二酚(3,5-DCC)。该紫外光解途径经过对氯(Cl)离子和碳(C)离子的质量衡算得以确认。随后对TCP进行生物降解,结果表明,TCP生物降解时,经过紫外光解预处理后的TCP溶液,其可生化性明显要优于未经过紫外光解预处理过的TCP溶液。这是由于经过紫外光解之后的TCP对微生物的抑制性得到缓解。最后对吡啶进行紫外光解研究,结果表明,吡啶经过紫外光解之后,也同样会生成一定的中间产物,如羟基吡啶,尤其是生成的有机羧酸,如丁二酸和甲酸。经过对吡啶中间产物进行质量平衡,并以此验证推测出的吡啶生物紫外光解途径。对经过紫外光解的吡啶溶液再进行生物降解研究,结果表明,经过紫外光解之后的吡啶溶液,其可生化性要明显优于未经过紫外光解的吡啶,其生物降解速率提高了20%至40%。总之,对于苯酚、氯酚和吡啶三种难降解有机物,经过紫外光解进行预处理后,它们的生物降解速率都有明显提高。该研究成果可以为类似的工业废水的实际处理提供理论依据和实践基础。
[Abstract]:With the rapid development of industrial production, a large number of pollutants are discharged into the natural water body. As a result, surface water and even groundwater are seriously polluted. Among them, some organic pollutants, which are difficult to biodegrade, exist in natural water bodies. Biological treatment is the preferred method, because the most prominent advantage of biological treatment technology is that it is economical and feasible, and can be easily applied in practice, but the treatment of refractory organic wastewater. The biological treatment method is difficult to reflect its superiority when it is only treated by a single biological method, because most of the refractory organic pollutants have certain biological inhibition to microorganisms. Some even have biological toxicity. In this paper, the common organic matter in industrial production, Phenol 2, 4. 6-trichlorophenol (TCPP) and pyridine were studied. Their donor characteristics were all organic pollutants with benzene ring as the basic structure. It was found that the three pollutants were Guang Min, and after UV photolysis, they would produce a certain intermediate product, and organic acid would become an endogenous electron donor. It can accelerate the biodegradation of refractory organic pollutants. Firstly, phenol is hydrolyzed by ultraviolet light. In the process of UV photolysis, phenol first forms hydroquinone and catechol, respectively. At the same time, a small amount of organic acid was formed. On the basis of this, the UV photodissociation pathway of phenol was proposed. The mass balance of the intermediate products was calculated. The results confirmed the photolysis pathway of phenol. In the subsequent biodegradation process, the samples without UV photolysis were used as the reference. The biodegradation rate of phenol was increased by 39% after UV photolysis. Secondly, the UV photolysis of TCP was carried out, and it was found that TCP was in the process of UV photolysis. The chlorine ions at the ortho (position 6) preferential shedding to produce 2o 4-dichlorophenol, followed by further dechlorination to produce 4-chlorophenol. At the same time, a hydroxyl group was added to the 6 site to form 3. 5-dichloro-catechol 3 ~ (5) DCCs. The UV photolysis pathway was confirmed by mass balance of chloro-chloro-Cl and C) ions. Subsequently, TCP was biodegraded and the results showed that. During the biodegradation of TCP, the TCP solution was pretreated by UV photolysis. Its biodegradability is obviously superior to that of TCP solution without UV photolysis. This is due to the abatement of the inhibition of microorganism by TCP after UV photolysis. Finally, the UV photolysis of pyridine was carried out. . The results show that pyridine also produces some intermediate products, such as hydroxy pyridine, especially organic carboxylic acid, after UV photolysis. For example, succinic acid and formic acid. Through the mass equilibrium of pyridine intermediate product, and verify the deduced pathway of pyridine biodegradation, the pyridine solution after UV photolysis was biodegradable. The results showed that the biodegradability of pyridine solution after UV photolysis was obviously better than that of pyridine solution without UV photolysis, and the biodegradation rate of pyridine solution was increased by 20% to 400.In short, for phenol. Chlorophenol and pyridine are three kinds of refractory organics, which are pretreated by UV photolysis. The results of this study can provide theoretical and practical basis for the practical treatment of similar industrial wastewater.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703

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