纳米零价铁降解污染物碘造影剂的过程和机理研究

发布时间：2018-01-14 10:48

本文关键词：纳米零价铁降解污染物碘造影剂的过程和机理研究　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：碘造影剂(Iodinatedcontrastmedia,ICM)被广泛用于在诊断检查期间内部身体结构如器官,血管和软组织的成像,一般会通过人体排泄尿液进入污水系统。传统的污水处理方法无法有效去除碘造影剂,导致其在环境中的积累和同化到生物系统中,会对环境及人体造成长期的不利影响。另一方面,纳米零价铁(Nano zero-valent iron,nZVI)独特的性能被广泛应用于各类污染物的去除。本文以典型的碘造影剂泛影酸钠(Diatrizoatesodium,DTA)为研究对象,分别研究了厌氧以及好氧条件下纳米零价铁(nZVI)对其的降解过程和机理,研究结果将为污染物碘造影剂的强化去除提供技术支持并推动纳米零价铁的应用。本文的研究内容和主要结论如下:1、厌氧条件下研究了 nZVI对DTA的还原脱卤作用的可行性,考察并探究了 DTA脱卤后产物的可生化性。研究发现,厌氧条件下nZVI可以有效的进行DTA的脱卤去除。DTA的降解效效率随着nZVI剂量的增加而增加,随着溶液pH值升高而降低,nZVI陈化时间对DTA脱卤有负面影响;低浓度的天然有机质可以提高DTA降解效果,而在高浓度下则有负面影响:与硫酸盐不同,硝酸盐和磷酸盐的存在强烈抑制DTA去除。另外,相比于DTA本身,还原产物DAB A可以通过好氧生物处理降解,说明利用nZVI对DTA脱卤后其产物的可生化性得到了较为显著的提高。2、好氧条件下研究了 nZVI对DTA降解的可行性,考察了 nZVI剂量、溶液pH、竞争性阴离子等对DTA降解的影响,并探究DTA的降解机理。研究发现好氧条件下利用nZVI也可以实现DTA的降解。DTA降解效率随着nZVI剂量的增加而增加,随着溶液pH值升高而降低,硝酸盐的存在强烈抑制DTA去除,而磷酸盐的存在却没有明显的影响。然而,DTA降解过程中总有机碳去除效果不佳,表明好氧条件下利用nZVI无法有效实现DTA的矿化。机理研究结果表明,好氧条件下nZVI降解DTA既有脱卤反应,也存在高级氧化过程。
[Abstract]:Iodine contrast media (ICM) is widely used in imaging internal body structures such as organs, blood vessels and soft tissue during diagnostic examinations. The traditional sewage treatment method can not effectively remove iodine contrast agent, resulting in its accumulation and assimilation into the biological system in the environment. On the other hand, the nanocrystalline zero-valent iron Nano zero-valent iron can cause long-term adverse effects on the environment and human body. The unique properties of nZVI have been widely used in the removal of various pollutants. In this paper, the typical iodine contrast agent Diatrizoatesodium DTAs was used as the research object. The degradation process and mechanism of NZVI were studied under anaerobic and aerobic conditions. The results will provide technical support for the enhanced removal of iodine contrast agent and promote the application of nanometer zero-valent iron. The research contents and main conclusions of this paper are as follows: 1. The feasibility of dehalogenation of nZVI on DTA was studied under anaerobic conditions. The biodegradability of the dehalogenated products of DTA was investigated. Under anaerobic conditions, nZVI could effectively dehalogenate DTA. The degradation efficiency of DTA increased with the increase of nZVI dose, and decreased with the increase of pH value of the solution. The aging time of nZVI has a negative effect on DTA dehalogenation. Low concentrations of natural organic matter can improve the degradation of DTA, but at high concentrations, there is a negative effect: unlike sulfate, the presence of nitrate and phosphate strongly inhibit DTA removal. Compared with DTA itself, the reduction product DAB A can be degraded by aerobic biotreatment, which indicates that the biodegradability of DTA dehalogenated by nZVI is improved by 2.2. The feasibility of DTA degradation by nZVI was studied under aerobic conditions. The effects of nZVI dosage, pH of solution and competitive anion on DTA degradation were investigated. The degradation mechanism of DTA was investigated. It was found that the degradation efficiency of DTA could also be achieved by using nZVI under aerobic conditions with the increase of nZVI dosage. With the increase of pH value of the solution, the presence of nitrate strongly inhibited the removal of DTA, but the presence of phosphate had no obvious effect. However, the removal of total organic carbon was not good during the degradation process. The results show that the mineralization of DTA can not be realized effectively by using nZVI under aerobic conditions. The results of mechanism study show that the degradation of DTA by nZVI under aerobic conditions has both dehalogenation reaction and advanced oxidation process.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;TQ421.7

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