【作者】 赵建伟；

【导师】 黄廷林；

【作者基本信息】 西安建筑科技大学 ， 市政工程， 2006， 博士

【摘要】 富营养化水体中的蓝藻水华可导致微囊藻毒素（MC）含量升高，MC是肝毒素和肿瘤促进剂，其化学性质稳定，常规水处理工艺不能有效将其脱除，由此对饮用水的安全带来很大威胁。本文以天津市富营养化原水中的MC为研究对象，开展了MC分析方法、水华蓝藻中MC的提纯及鉴定、水中MC去除技术和MC氧化降解动力学及机理四个方面的深入研究，并取得了一定的成果。首先，对MC的HPLC检测条件和SPE富集条件进行了优化，在此基础上建立了高效、灵敏的SPE-HPLC富集分析检测方法，该方法具有很好的重现性、精密度和回收率，对MC的最低检测限可达0.1μg／L，适合用来分析水体中的痕量MC。根据MC的分子特性，对其质谱检测参数进行了优化，并与HPLC有机结合建立了MC的HPLC-ESI／MS分析方法，该方法进一步提高了检测的灵敏度，将绝对检测限降至pg级，且能有效进行MC及其降解产物的定性分析，为MC各方面研究工作的深入打下基础。围绕天津水华蓝藻，进行了MC提取、纯化及鉴定的研究工作。通过实验研究，优化了MC的提纯方法，该方法具有提取效率高、重现性好、提取毒素中杂质含量低等特点，可有效从水华蓝藻中提纯MC；调查发现，天津富营养化表层原水中的水华蓝藻主要由微囊藻组成，其在富集后藻浆液中所占比例超过90％；利用优化的提纯方法从水华蓝藻中提取出MC，并利用HPLC及HPLC-ESI／MS方法对提纯的MC样品进行了定性和定量分析，结果表明原水中的藻类可产生MCRR和MCLR两种毒素，且产毒强度较高，分别为432.89和322.51μg／g藻干重。通过对去除MC的单元工艺及其组合技术的研究发现：常规水处理工艺对MC的去除率较低，一般在50％以下，混凝甚至可导致水中DMC含量增加而出现负去除率；考察的三种预氧化剂氯、高锰酸钾和臭氧在适宜的投加量下均能较好地去除MC，且增加投加量可提高去除效果；常规工艺前设置预氧化工艺可提高对MC的去除率，且可避免由单独预氧化或单独混凝工艺造成的水体中DMC增加的现象；单独PAC吸附对DMC去除效果较好，对IMC去除效果较差，但整体对TMC的去除效果较差，去除率在30％左右，PAC经氧化改性后表面结构和表面化学性质发生变化，对藻毒素的去除效果有所提高；O₃和PAC的协同作用提高了对MC的去除率，去除效果好于两者单独应用；O₃预氧化+PAC吸附+混凝沉淀的联合工艺对水中TMC的去除率超过80％，可有效控制水中MC的含量；O₃预氧化+常规气浮、O₃预氧化+PAC吸附+常规气浮以及O₃预氧化+氧化改性PAC吸附+常规气浮三种组合工艺均能有效去除水中MC，对TMC的去除率分别达到85.3％、91.6％和96.2％；经组合工艺处理后，过滤出水中藻毒素的含量已很低，甚至在水体中消失，且后两种工艺能更好的去除水体中有机物；中试系统中常规工艺后的中间氧化、催化氧化、生物活性碳、消毒等深度处理工艺对水体中残留的MC有明显的去除效果，可将水中MC降至检测限以下，有效的保障了水厂出水的安全性；最后通过综合比较单元工艺及其组合工艺对MC、藻类以及有机物的去除效果，提出了针对富营养化原水制水工艺的选择依据。通过考察不同条件下氯、高锰酸钾和臭氧对MCLR的降解特性发现：三种氧化剂对MCLR的降解过程均呈准一级动力学模式，即ln（C／C₀）=-kt，且相关性较好；反应速率与MCLR的起始浓度无关，而受氧化剂初始浓度影响较大，与氯和高锰酸钾初始浓度成正比，与臭氧初始浓度的1.5次方成正比。提高反应温度有利于加速氧化剂对MCLR的降解，但影响并不显著，有效氯、高锰酸钾和臭氧降解MCLR的反应活化能分别为15.86、18.17、25.38kJ／mol；臭氧对MCLR的降解受pH值影响较大，随着pH值的增大降解速率迅速提高。通过对降解产物分子量及结构的分析，发现三种氧化剂降解MCLR的机理有所不同：有效氯可先与MCLR发生亲电加成反应生成氯乙醇-MCLR，再通过亲质子置换反应生成二羟基-MCLR；而高锰酸钾可直接将MCLR氧化成二羟基-MCLR，并在高锰酸钾过量的情况下可进一步氧化成二羰基—MCLR；臭氧可迅速将MCLR氧化成二羟基-MCLR，并瞬间将其进一步氧化成酮类或醛类有机物，在此过程产生的H₂O₂催化作用下，上述降解产物可被进一步氧化成羧酸类有机物。更多还原

【Abstract】 Cyanobacterial blooms in the eutrophic water could direct cause the concentration of Microcystin （MC） increases. MC is hepatotoxin and tumor promoter, its chemical property is so stable that conventional water treatment processes can not remove it effectively. This brought a great threat to the safety of drinking water. Around MC in Tianjin’s eutrophic water , the research were carried out successfully which included analytical method, purification and identification means , removal technique, oxidative degradation kinetics and mechanism.The high performance liquid chromatography （HPLC） detection of MC and the solid phase extraction （SPE） enrichment of MC were optimized, and then the highly effective and sensitive SPE-HPLC method was established, which have good reproducibility, precision and returns-ratio. The minimum detection limit could achieve 0.1μg/L. So it adapts to analysis the trace MC in water. After the optimization of mass spectrum examination parameter according to the MC molecule properties, the organic combination of HPLC with MS formed the HPLC-ESI/MS analytical method which increased the sensitivity further, cut down the detecting limit to pg level. This method is also able effectively to carry out the qualitative analysis of MC and its degradation product, which lays the foundation for the in-depth study of MC.The research was carried on about the extraction, purification and identification of MC. Through the experimental study, the purification method of MC was optimized, which has the characteristics of high extraction rate, good reproducibility and low impurity content and can effectively purify MC from water blooms. The investigation discovered that the microcystis is major intergrant of cyanobacteria in Tianjin’s eutrophic water and its content is over 90 percent. Using the HPLC and HPLC/ESI-MS method to analyze qualitatively and quantitatively of MC sample purified from cyanobacteria, it indicated that the alga in the raw water may produce two kind of microcystin such as MCRR and MCLR, and each intensity was higher, respectively 432.89 and 322.51μg / g dry weight of algae.Through the comparison of MC removal effects in unit technologies and their combination, several conclusions achieved as follow: MC could be only removed by less than 50 percent in conventional water treatment process, and coagulation even resulted in deficit removal efficiency because of the DMC content increasing. Three pre-oxidants such as chlorine, potassium permanganate and ozone could remove MC effectively with appropriate dosage, and increase of the dosage may improve the removal efficiency. Setting up pre-oxidation before conventional process can increase the removal rate of MC; it eliminates the phenomenon of MC’s increase which due to the separate pre-oxidation or coagulation process. The adsorption of a single PAC was efficiency to the removal of DMC and inefficiency to IMC, while it was inefficiency to TMC for about 30 percent removal rate; The surface texture and chemical properties of PAC was modified by oxidation to enhance the removal of MC. The synergistic action of ozone and PAC was more conductive to the removal of MC than their application alone. The combined process of pre-oxidation of ozone + PAC adsorption + coagulation and sedimentation had over 80 percent removal rate of TMC to control the MC content in water effectively; three kinds of combined process such as pre-oxidation of ozone + conventional gas floatation, pre-oxidation of ozone + PAC adsorption + conventional gas floatation and pre-oxidation of ozone + modified PAC adsorption + conventional gas floatation could remove the MC effectively and the removal rate of TMC was 85.3, 91.6 and 96.2 percent in turn. After treated by combined processes, the MC in filtered water was very low even disappeared, and the two later could remove organic more effectively. In experiment system, the deep treatment followed conventional processes, such as medial oxidation, catalysis oxidation, biological active carbon, disinfection and so on, could ensure the water from plant safety because the removal effects to the residual MC were clear as to detecting limit below. Finally, through the comprehensive comparison of the removal effects of MC, alga and organic in unit and combined processes, it suggested a basis for the selection of water treatment processes suitable to eutrophia source water.Through the comparison of degradation properties of MCLR by chlorine, potassium permanganate and ozone under different conditions, it was found that the MCLR degradation processes of three oxidants complied with pseud-first-order kinetics mode as ln（C/C₁） =-kt. reaction rate had nothing to do with initial concentration of MCLR, while influenced greatly by oxidant initial concentration that were direct ratio to chlorine and KMnO₄ and 1.5 power direct ratio to ozone. Increase temperature did well to accelerating degradation but not outstanding. Reaction activation energy between MCLR and active chlorine, KMnO₄ and ozone were 15.86, 18.17, 25.38kJ/mol in turn. pH had great influence on the degradation of MCLR by ozone and increase of pH accelerated degradation.The analysis of the molecular weight and texture of degradation products discovered that mechanism of MCLR degradation by three oxidants were different. Active chlorine could take place additive reaction with MCLR to generate chlorohydrin-MCLR, and the halogen in the chlorohydrin may then undergo a nucleophilic substitution reaction with the solvent to form dihydroxyl-microcystin. While KMnO₄ could oxidize MCLR to dihydroxyl-MCLR directly, and under the condition of excessive KMnO₄, it could further oxidize to dicarbonyl-MCLR. Ozone could quickly oxidize MCLR to dihydroxyl-MCLR and further oxidize to alkone or aldehyde organic immediately. Under H₂O₂ catalysis action which generated during the course, above degradation products could further oxidize to carboxylic acid organic.更多还原