【作者】 王珂；

【导师】 梁文艳；

【作者基本信息】 北京林业大学 ， 环境科学， 2008， 硕士

【摘要】 我国湖泊富营养化问题日益突出,水体中藻类的大量繁殖,造成生态环境和水质严重恶化,人们的饮用水安全遭受严重威胁,各种除藻杀藻技术成为当前的研究热点。其中电催化氧化技术因其操作简便易于实现自动化、与环境兼容等优点而备受关注。本论文建立了中性红染色法和TTC—脱氢酶还原法两种细胞活性测定法,对电催化氧化过程中,藻细胞活性的变化进行了研究。并从藻细胞活性的变化、溶液性质的改变入手研究了电催化氧化的灭藻效能及影响因素。从电流、羟基自由基、溶液pH等方面对电催化氧化灭藻的机制进行了探索。藻细胞活性检测方法研究的结果表明:TTC-脱氢酶还原法可以检测铜绿微囊藻细胞活性,并能很好地进行定量化测定。测定的最适条件是:pH=7.5~8.0 Tris-HCl作缓冲液配置0.2%氯化三苯基四氮唑(TTC),将细胞接入其中,于30~35℃培养8h~16h后,用50%乙醇提取细胞中还原生成的三苯甲臜(TPF),再用正己烷萃取去除色素干扰。而中性红染色法主要用于检测藻细胞个体完整性,0.02%中性红染色15min是染色的最佳条件。电催化氧化的灭藻效能研究中发现电催化氧化法具有较好的灭藻效果,细胞密度约为4×109~6×109个/L时,在4mA/cm2电流密度下以Na2SO4溶液为电解质处理7min,藻细胞脱氢酶活性大幅下降,TPF吸光值降至0.365,中性红染色率为30.1%,此时藻细胞再接入培养基中培养也无法繁殖生长,彻底失活。灭藻效果影响因素研究发现电流密度、反应时间和反应初始藻细胞密度对电催化氧化灭藻过程起着重要作用。增大电流密度、延长反应时间和降低初始细胞密度都能使藻细胞活性变弱,达到良好的灭藻效果。电解质种类对灭藻效果影响不显著,但直接以自然水体作为电解质,电催化氧化过程中藻细胞活性迅速下降,且没有剧毒的副产物生成。电解质离子强度对灭藻效果影响不大。电催化氧化灭藻的机制研究结果表明,电催化氧化灭藻是由电流、电场与自由基共同作用完成的,其中羟基自由基起主要作用。电催化氧化藻细胞过程中,溶液pH值的改变对藻细胞活性有一定影响。更多还原

【Abstract】 Eutrophication is becoming increasingly prominent in china. The massive propagation of algae is seriously worsening the ecological environment and the water quality, threatening the safety of drinking water. Many kinds of technology to eliminate algae and kill algae are the focus of the current research. The electrocatalysis oxidation technology which is simple, easily automation and compatible with the environment, has received many attention.Two measuring methods of cell viability which are the neutral red dyeing and the TTC- dehydrogenase activity determination are established in this paper. Study on the change of algae viability in the process of the electrocatalysis oxidation by the methods. From the change of algae viability and solution properties, it studies on the effectiveness and influencing factors of algae inactivation in the process of the electrocatalysis oxidation. The mechanism of algae inactivation by the electrocatalysis oxidation includes the current, hydroxyl radical, the pH value and so on. These aspects have been preliminarily explored.The results of research into algae viability detection show that: the method for TTC-dehydrogenase activity can detect the viability of microcystis aeruginosa, and make a quantitative determination well. The optimal conditions of determination is pH=7.5~8.0, Tris-HCl as a buffer solution deploy 0.2% TTC. Cell raise in the slution 8h~16h in 30~35℃, then extract TPF with 50% ethyl alcohol, at last use Hexane as extractant to remove pigment interference. The method of neutral red dyeing is mainly used to detect the integrity of individual algae cells, 0.02% neutral red dyes for 15min is the optimum condition.Studying on the effectiveness of algae inactivation in the electrocatalysis oxidation, we find the Ti/RuO2 electrocatalysis oxidation system has a better effectiveness of algae inactivation. When cell density is approximately 4×109~6×109/L and current density is 4mA/cm2, use Na2SO4 as electrolyte to treat sample for 7min, the dehydrogenase activity has a sharp decline, and the absorption value of TPF drops to 0.365, the dyeing rate of neutral red is 30.1%. At this time algae cell is unable to reproduce the growth even it is raised again in MA culture medium. We think cell is thoroughly inactivation.Studying on factors of algae inactivation in the process of the electrocatalysis oxidation, we find the current density, the reaction time and the cell initial density, play a important role in algae inactivation by the electrocatalysis oxidation. Increasing the current density, extending the reaction time and reducing the density of initial cells, all can make algae activity weak. Electrolyte types for the effectiveness of algae inactivation is not significant, but natural water as the electrolyte, the algae viability in process of the electrocatalysis oxidation rapidly declines and no highly toxic by-product is produced.Studying on the mechanism of algae inactivation by the electrocatalysis oxidation, the results show that: the electrocatalysis oxidation is accomplished by the combined action of the current, electric field and free radical. The hydroxyl radical plays a leading role. The change of pH value has little impact on the algae viability.更多还原