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题名: Ce-MCM-48催化削减臭氧氧化过程中溴酸根生成势的效能与机理
作者: 陆晓巍
学位类别: 硕士
答辩日期: 2010
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 强志民 ; 张涛
关键词: MCM-48 ; ; 臭氧氧化 ; 溴酸盐生成势 (BFP) ; 水处理
中文摘要:       臭氧具有杀菌和氧化有机物的作用,被广泛地应用于饮用水处理中。如果水中含有溴离子(Br-),在臭氧氧化过程中会生成溴酸根(BrO3-)。BrO3-是一种具有潜在致癌性的臭氧化副产物。多相催化臭氧化技术可以强化对单独臭氧化难去除的有机物的能力,选择合适的催化剂,可以在臭氧氧化过程中削减BrO3-生成势。本论文在实验室中合成了不同Si/Ce比(200、100、66和30)的骨架含铈(Ce)的介孔分子筛MCM-48,研究了它们在含Br-水臭氧氧化过程中对BrO3-生成势的削减作用。合成的催化剂通过X射线衍射(XRD)、氮气(N2)吸附—解吸、X射线光电子能谱(XPS),零电荷点(pHpzc)等手段进行了表征。在合成的催化剂中,Si/Ce比为66的MCM-48(Ce-MCM-48(66))可以最有效地削减BrO3-生成势(> 90%),同时可以强化臭氧氧化去除水中具有代表性的难去除农药——莠去津(atrazine)还。另外,Ce-MCM-48(66)在半连续实验中显示出了良好的持续削减BrO3-生成势的效能。溶液pH值在5.5 ~ 9.5范围内,Ce-MCM-48(66)催化臭氧化(O3/Ce-MCM-48(66))对BrO3-生成势的削减率保持较高水平。 关于无机溴吸附、溴元素平衡、臭氧衰减的进一步研究揭示了O3/Ce-MCM-48 (66)相对于单独臭氧氧化削减BrO3-生成势的机理。结果显示Ce-MCM-48(66)对BrO3-,Br-和HOBr/OBr-没有明显的吸附。相对于单独臭氧氧化,在O3/Ce-MCM-48(66)加速了臭氧(O3)分解,抑制了分子O3氧化Br-生成次溴酸/次溴酸跟(HOBr/OBr-)。Ce-MCM-48(66)削减BrO3-生成势的另一个原因可能是其在臭氧氧化过程中降低了生成的H2O2的生成浓度。
英文摘要:
      Ozone is commonly used for bacteria disinfection and organic pollutant oxidation in drinking water treatment. Bromate (BrO3-) will be generated during ozonation if water contains bromide (Br-). BrO3- is a potentially carcinogenic ozonation byproduct. Heterogeneous catalytic ozonation, which is designed to improve recalcitrant pollutant removal during ozonation, may be applied to minimize the bromate formation potential (BFP) through choosing appropriate catalyst. This work investigated the synthesis of cerium (Ce) incorporated mesoporous sieves, MCM-48 with different Si/Ce ratios (i.e., 200, 100 and 66) and their effectiveness on the BFP minimization during ozonation of Br--containing water. The prepared catalysts were characterized with X-ray diffraction (XRD), Nitrogen (N2) adsorption-desorption, X-ray photoelectron spectroscopy (XPS) and pH of surface zero charge (pHpzc). Among the catalysts synthesized, the Ce-MCM-48 with the Si/Ce ratio of 66 could most effectively minimize the BFP (> 90%) and simultaneously enhance the degradation of a model pesticide compound, atrazine which is hard to remove during ozonation. In addition, the Ce-MCM-48 (66) exhibited a steady activity in minimizing BFP during semi-continuous experiments. The percent reduction of BrO3- in catalytic ozonation with Ce-MCM-48(66) (O3/Ce-MCM-48 (66)) maintained at high levels in the range of solution pH form 5.5 to 9.5. Additional experiments on inorganic bromine species adsorption, bromine mass balance, and ozone decomposition clarified the mechanism of BFP minimization during O3/Ce-MCM-48 (66) in comparison to ozonation alone. Results indicate that the adsorption of BrO3-, Br- and HOBr/OBr- on the catalyst was insignificant. Compared with ozonation alone, O3/Ce-MCM-48 (66) accelerated O3 decomposition, thus inhibited the oxidation of HOBr/OBr- to BrO3- by molecular O3. Another possible reason for BFP minimization by Ce-MCM-48 (66) might exist in that it reduced the concentrations of H2O2 generated from ozone decomposition.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35015
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
陆晓巍. Ce-MCM-48催化削减臭氧氧化过程中溴酸根生成势的效能与机理[D]. 北京. 中国科学院研究生院. 2010.
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