DOM的光降解及其对典型污染物环境行为的影响

发布时间：2018-01-26 02:33

本文关键词： DOM 四环素模拟太阳光光降解　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着畜禽养殖业的快速发展，畜禽粪便产生量逐年增大，未经处理的畜禽粪便中含有高浓度的溶解性有机质（Dissolved organic matter，DOM）和未被完全吸收的抗生素，这些物质可以通过浸出、淋溶等过程进入环境。DOM是一种性质活泼的混合物，自身可以发生光降解，对水体环境中其它污染物的光化学过程也具有重要影响。同时，抗生素及其代谢物具有高度亲水性和生物稳定性，可在环境中迁移和蓄积，影响人体健康。因此，研究畜禽粪便DOM以及抗生素在环境中的光降解行为具有重要意义。本论文以大型养鸡场鸡粪为DOM来源，研究了DOM在水相和冰相中的光降解行为，以及光降解前后DOM的性质变化；考查了DOM的光降解对DOM与Cu2+、Zn2+结合性的影响；以应用最为广泛的抗生素——四环素（Tetracycline，TC）为代表，研究了其在水相和冰相中的光降解行为，，以及DOM对TC光降解的影响。论文主要得到如下结论：（1）在水相+模拟太阳光体系，DOM在5～40mg/L范围内，其光降解率先增大后减小，且浓度为20mg/L的DOM有最大光降解率；酸性和碱性条件均抑制了DOM的光降解；提高温度有利于DOM的光降解。（2）紫外光作用下，在水相中，20mg/L DOM光照48h降解率达85%。然而，在模拟太阳光作用下，无论在水相还是冰相中，DOM光解均非常缓慢，光照48h降解率只有7.2%和4.5%。（3）在水相+紫外光和水相+模拟太阳光体系中，随光照时间的增加，DOM的芳香度降低，且腐殖类物质和类富里酸物质含量减少；在冰相中，经模拟太阳光照，冻融作用令DOM的芳香度有所下降。（4）在三个体系下，DOM溶液的pH均随光照时间的增加而减小，但在水相+紫外光体系中，pH减小幅度比另外两个体系大。（5）在水相+紫外光、水相+模拟太阳光体系中，DOM经光照后，分子量35000Da部分的含量均有所减少，而中等分子量和小分子量部分的总含量均有所增加，尤其是在紫外光条件，分子量35000Da部分的含量减少更明显，而在冰相+模拟太阳光体系中DOM的分子量分布并无明显变化。（6）在水相+模拟太阳光和水相+紫外光体系中，DOM与Cu2+、Zn2+的结合性均随光照时间增加明显下降，而在冰相+模拟太阳光体系中的结合性无明显变化。（7）5～40mg/L TC在水相+模拟太阳光和冰相+模拟太阳光体系中的光降解均符合一级动力学方程，且在前一体系下的降解率明显高于后一体系。（8）DOM的加入均促进了20mg/LTC在两个体系中的光降解，但对冰相+模拟太阳光体系中TC的光降解的促进作用更为明显，且经不同光照时间后的DOM对TC光降解的促进作用也并不相同。
[Abstract]:With the rapid development of livestock and poultry breeding industry, the amount of animal manure production is increasing year by year. Untreated animal feces contain high concentrations of dissolved organic matter (dissolved organic matterus) and antibiotics that have not been completely absorbed. These substances can be leached, leaching and other processes into the environment. Dom is a kind of active mixture, which can be photodegraded by itself. At the same time, antibiotics and their metabolites are highly hydrophilic and biostable, and can be transported and accumulated in the environment. Therefore, it is of great significance to study the photodegradation of DOM in animal feces and antibiotics in the environment. In this paper, the photodegradation behavior of DOM in water and ice phase and the changes of DOM properties before and after photodegradation were studied using chicken manure as DOM source in large chicken farms. The effect of photodegradation of DOM on the binding of DOM to Cu2 zn _ 2 was investigated. The photodegradation behavior of tetracycline tetracycline (TCC), the most widely used antibiotic in aqueous and ice phases, was studied. And the effect of DOM on the photodegradation of TC. (1) in the range of 5 ~ 40 mg / L of Dom in aqueous simulated solar system, the photodegradation of Dom increased first and then decreased, and the maximum photodegradation rate of 20 mg / L of DOM was observed in the range of 5 ~ 40 mg / L ~ (-1) 路L ~ (-1) 路L ~ (-1) 路L ~ (-1); Both acidic and alkaline conditions inhibited the photodegradation of DOM. Increasing the temperature is beneficial to the photodegradation of DOM. The degradation rate of 20 mg / L DOM in aqueous phase under UV irradiation for 48 h reached 85%. However, under simulated solar light, both in water phase and ice phase, the degradation rate was 85%. DOM photolysis was very slow, and the degradation rates were only 7.2% and 4.5 after 48 h illumination. 3) the aromaticity of Dom decreased and the contents of humic and fulvic acid-like substances decreased with the increase of light time in aqueous ultraviolet and water-simulated solar system. In the ice phase, the aromaticity of DOM was decreased by freezing and thawing after simulated solar illumination. (4) in the three systems, the pH of Dom solution decreases with the increase of light time, but in the aqueous ultraviolet light system, the pH decrease is larger than that in the other two systems. (5) in the aqueous ultraviolet light, the contents of the molecular weight of 35000Da in the aqueous simulated solar system were decreased after irradiation. However, the total content of medium molecular weight and small molecular weight part increased, especially in ultraviolet light, the molecular weight of 35000Da part decreased more obviously. However, the molecular weight distribution of DOM does not change obviously in the ice-simulated solar system. (6) the binding properties of Dom and Cu2 ~ (2 +) Zn _ (2) in aqueous phase simulated solar system and aqueous phase ultraviolet light system decreased obviously with the increase of illumination time. However, there is no obvious change in the binding property in the ice phase simulated solar system. The photodegradation of 40 mg / L TC in both aqueous and ice-simulated solar systems accords with the first-order kinetic equation. The degradation rate in the former system was significantly higher than that in the latter system. The addition of Dom promoted the photodegradation of 20mg / LTC in the two systems, but the photodegradation of TC in the ice-simulated solar system was more obvious. The effect of DOM on the photodegradation of TC was different after different illumination time.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X713

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