臭氧氧化诺氟沙星及其产物生物毒性研究

发布时间：2018-02-07 09:25

  本文关键词： 诺氟沙星 臭氧氧化 中间产物 生态毒性 发光菌 斑马鱼　出处：《山东建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：水环境中抗生素的残留对生态环境以及人类健康构成的威胁日趋严重,而现有污水处理技术难以对其有效去除。臭氧作为一种氧化能力较强的氧化剂,能有效去除抗生素母体,然而有毒副产物的产生是困扰臭氧技术应用的主要问题。本课题以诺氟沙星为目标抗生素,臭氧氧化为技术手段,主要研究了臭氧对诺氟沙星的降解能力及降解过程中产生的中间产物的可生物降解性能;以发光菌的发光率为毒性评价手段,通过研究诺氟沙星及臭氧氧化诺氟沙星中间产物对发光菌抑制作用探讨了臭氧氧化前后诺氟沙星毒性变化,并推测了可能的中间产物;利用斑马鱼为受试生物,针对诺氟沙星及臭氧氧化诺氟沙星中间产物对斑马鱼死亡率及微核率进行研究,考查了臭氧氧化诺氟沙星中间产物的毒理性。研究结果如下:臭氧氧化初始浓度为5mg/L的诺氟沙星溶液,去除率随着臭氧投加量的增加而逐渐升高,通过研究pH对去除率的影响,可发现,臭氧对诺氟沙星的氧化效果在pH11的环境下要比pH3的环境下好,但去除率也并非一直升高,当臭氧投加量大于10 mg/L时,去除率均趋于平缓。对臭氧氧化诺氟沙星过程中指标变化测定显示,当pH3的氧化环境且臭氧投加量为20mg/L时,臭氧氧化诺氟沙星溶液过程中对DOC的去除效果最佳,UV_(254)在不同的pH氧化条件下,基本都是逐渐降低的趋势,且pH 11条件下对UV_(254)的去除效果相较与另两个条件而言效果略差;随着臭氧投加量的增加,诺氟沙星中的N原子经氧化逐渐脱离诺氟沙星游离出来,以氨氮和NO3—形式存在。臭氧氧化诺氟沙星后的溶液生物降解性逐渐升高,说明生成的中间产物易于生物降解。费氏弧菌的发光抑制率与诺氟沙星浓度有较强的相关性,诺氟沙星初始浓度为500mg/L时,诺氟沙星对费氏弧菌的发光抑制率为65%左右。臭氧氧化诺氟沙星中间产物对发光菌发光抑制研究表明,pH11的氧化条件下,氧化后的溶液对费氏弧菌的发光抑制率随时间的递增呈现一直升高的趋势,通臭氧时间相同的前提下发光抑制率均低于pH3和pH7的结果。对臭氧氧化诺氟沙星中间产物分析,中间产物HCHO的生成受氧化环境pH的影响,酸性条件下甲醛的生成要低于中性和碱性条件,从生物砂对甲醛的降解作用来看,虽不能完全降解但降解作用也较为稳定,都能将HCHO降至0.7mg/L以下。斑马鱼微核率随着诺氟沙星浓度的升高呈现上升趋势,说明诺氟沙星浓度越大,致突变率越高,毒性就会越大。以250 mg/L的诺氟沙星溶液为原液,伴随臭氧浓度的增加,诺氟沙星中间产物对斑马鱼红细胞微核率的影响出现急剧下降,当臭氧投加量为2.5mg/L时,斑马鱼红细胞微核率为2‰,并且随着臭氧投加量的增多微核率逐渐升高,当臭氧投加量达到10 mg/L时微核率基本稳定在3‰左右。
[Abstract]:Antibiotic residues in water environment pose more and more serious threats to ecological environment and human health, but it is difficult to remove them effectively by existing wastewater treatment technology. Ozone, as an oxidant with strong oxidation ability, can effectively remove antibiotic parent body. However, the production of toxic by-products is the main problem that puzzles the application of ozone technology. In this paper, norfloxacin as the target antibiotic, ozone oxidation as the technical means, The biodegradation ability of ozone to norfloxacin and the biodegradability of intermediate products produced during the degradation were studied. By studying the inhibitory effect of norfloxacin and norfloxacin intermediate products on luminescent bacteria, the toxic changes of norfloxacin before and after ozonation were studied, and the possible intermediates were speculated. Zebrafish were used as tested organisms. The mortality and micronucleus rate of zebrafish were studied by using norfloxacin and norfloxacin intermediate products. The toxicity of the intermediate product of norfloxacin by ozone oxidation was investigated. The results are as follows: the removal rate of norfloxacin solution with the initial ozone oxidation concentration of 5 mg / L increases with the increase of ozone dosage, and the effect of pH on the removal rate is studied. It was found that the oxidation effect of ozone on norfloxacin was better in pH11 than in pH3, but the removal rate did not always increase. When the amount of ozone added was more than 10 mg/L, The determination of the index changes in the process of ozone oxidation of norfloxacin showed that when the oxidation environment of pH3 and the dosage of ozone was 20 mg / L, In the process of ozonation of norfloxacin solution, the removal efficiency of DOC was the best. Under different pH oxidation conditions, the DOC removal effect was decreased gradually, and the removal effect of DOC was slightly worse at pH 11 than that under the other two conditions. With the increase of ozone dosage, the N atom in norfloxacin was oxidized and dissociated from norfloxacin and existed in the form of ammonia nitrogen and no _ 3-. The biodegradability of the solution of norfloxacin was gradually increased after ozonation of norfloxacin. The results showed that the intermediate product was easy to biodegrade, and the luminescence inhibition rate of Vibrio ferryi was strongly correlated with the concentration of norfloxacin, when the initial concentration of norfloxacin was 500 mg / L, The luminescence inhibition rate of norfloxacin against Vibrio flexneri is about 65%. The luminescence inhibition rate of the oxidized solution against Vibrio ferrovirii has been increasing with the increase of time, and the luminescence inhibition rate of the oxidized solution under the same ozone time is lower than that of pH3 and pH7. The intermediate products of norfloxacin ozonation were analyzed. The formation of intermediate product HCHO was influenced by the pH of oxidation environment, and the formation of formaldehyde in acidic condition was lower than that in neutral and alkaline condition. From the degradation of formaldehyde by biological sand, although it could not be completely degraded, the degradation effect was relatively stable. The micronucleus rate of zebrafish increased with the increase of norfloxacin concentration, indicating that the higher the concentration of norfloxacin, the higher the mutagenicity, the greater the toxicity. With the increase of ozone concentration, the effect of norfloxacin intermediate product on erythrocyte micronucleus rate of zebrafish decreased sharply. When ozone dosage was 2.5 mg / L, the micronucleus rate of zebrafish erythrocyte was 2 鈥，

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