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题名	水华污染的水体特征与微囊藻毒素光催化降解机理研究
作者	方艳芬
学位类别	博士
答辩日期	2011-05-26
授予单位	中国科学院研究生院
授予地点	北京
导师	程根伟
关键词	光催化 水华 藻毒素 降解机理
其他题名	Characteristic of Water Pollation of Algal Bloom and Photocatalytic Degradation Mechanism of Microcystis
学位专业	自然地理学
中文摘要	本论文分别制备和筛选了具有可见光活性的溴氧化铋（BiOBr）和异相Fenton催化剂，较为深入地研究了这两种催化剂降解微囊藻毒素-LR的机理，得到一些科学性的研究结果。 1. 在可见光照射下，制备的BiOBr能有效降解中性水体中的微囊藻毒（MC-LR）。通过质谱数据发现，在微囊藻毒素降解过程中出现了12种中间产物，BiOBr不仅造成藻毒素(2s,3s,8s,9s)-3-氨基-9-甲氧基-2,6,8-三甲基-10-苯基-4,6-二烯酸（Adda）链上的共轭二烯键和Ｎ-甲基脱氢丙氨酸（Mdha）基团上的不饱和双键的断裂，还具备去除D-异谷氨酸（D-Glu ），D-赤-β-甲基天冬氨酸（D-MeAsp）链上羧基和L-精氨酸(L-Arg)链上胍基的独特能力。BiOBr催化剂能选择性地破坏MC-LR的关键毒性部位，表明其将在治理饮用水处理上具有很大的应用前景。 2. 研究了BiOBr 催化剂在UV和可见光激发下所表现的降解行为和对应的活性氧的差异。结果发现，可见光照射下，产生大部分羟基自由基来自O2和导带电子的系列还原反应，它是导致底物有效降解的进攻途径之一。另一条途径是空穴直接氧化诱导的水解反应，使得表观上H2O中的氧进入氧化产物。 3. 在可见光照射下(λ>450 nm)，以负载Fe2+的NaY分子筛制备得到Fe2+-NaY催化剂（简称FeY），研究了FeY/H2O2降解微囊藻毒素-LR（MC-LR）的机理，推测了可能的降解路径和三处易被氧化的位点。
英文摘要	We prepared and selected bismuth oxide bromide (BiOBr) and heterogeneous Fenton catalyst (FeY), especially focus on the photocatalytic degradation mechanism of microcystin-LR using these catalysts. The details are as follows： 1. Bismuth oxide bromide, BiOBr, was used to catalyze the degradation of microcystin-LR (MC-LR) in water at neutral pH under visible light. During the investigation, twelve intermediates from MC-LR decomposition were identified by LC-MS. In addition to attacking MC-LR at the typically susceptible sites (i.e., the conjugated double bond of the Adda chain and terminal unsaturated bond of the Mdha chain), the BiOBr photocatalyst has the remarkable ability to decarboxylate the free acid groups on D-glutamic acid (Glu) and methyl-D-aspartic acid (MeAsp), and oxidizing guanidine group of L-arginine (L-Arg). Our results indicate that BiOBr, a photocatalyst that selectively destroys sites crucial to MC-LR toxicity, shows great promise as a means of effectively treating drinking water. 2. The Bismuth oxybromide photocatalysis mechanism was firstly proposed using Oxygen-18 isotopic labeling experiment and electron spin resonance spectral (ESR). The results indicate hydroxyl radical predominates the degradation of the substrates and efficient attacking involved two pathway. One is that the reduction reaction of H2O2 followed by the series reaction of O2 and electron on the conduction band. The another is that direct hole oxidation followed by the hydrolysis. 3. Under visible light irradiation (λ>450 nm), the degradation mechanism of microcystin-LR is studied using H2O2 and FeY catalyst, which is prepared by means of loading Fe2+ to the molecular sieve NaY. The results indicate the possible pathways and three vulnerable oxidation sites are put forward.
语种	中文
公开日期	2013-01-30
内容类型	学位论文
源URL	[http://192.168.143.20:8080/handle/131551/4863]
专题	成都山地灾害与环境研究所_山地表生过程与生态调控重点实验室
推荐引用方式 GB/T 7714	方艳芬. 水华污染的水体特征与微囊藻毒素光催化降解机理研究[D]. 北京. 中国科学院研究生院. 2011.

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