【作者】 梁志霞；

【导师】 梁文艳；

【作者基本信息】 北京林业大学 ， 环境科学， 2012， 硕士

【摘要】 水华蓝藻产生的藻毒素是破坏水质环境、影响人类健康的主要因素。本文以DSA电极(形稳电极)为阳极,通过电极材料、光电反应器、光电协同作用和影响因素的探讨,研究光电催化氧化法对藻毒素MCLR的降解效能,并采用发光菌急性毒性实验、蚕豆根尖微核实验和单细胞凝胶电泳实验,分析MCLR粗提液降解过程中水质急性毒性和遗传毒性变化,评价该方法的安全性。研究表明RuO2/TiO2电极对MCLR的降解效果最好,这与其表面涂层均匀的龟裂状形貌、大量的锐钛矿型和金红石相的Ti02,较高的析氧电位和伏安电荷量有关。电极数量由2片增至6片时,MCLR去除率由55.9%提高到79.6%。浸入式光电反应器的电流效率高于外辐照式。电极表面的Ti02在光电催化氧化降解MCLR的过程中发挥了明显的光催化作用。光电催化氧化的去除率大于光催化氧化和电催化氧化之和,表明后两者的耦合过程产生了一定的协同作用。辐照光源和电流密度存在最佳匹配条件,分别为UVC辐照、电流密度10mA/cm2和UVA辐照、电流密度1.0mA/cm2,此条件下光电协同作用最显著。在光电催化氧化过程中,随极板间距增大而出现的去除率下降取决于电催化过程,而不是光催化过程；MCLR去除率随其初始浓度增加而减小。MCLR粗提液具有较强的毒性,能够抑制发光菌发光、诱导蚕豆根尖产生微核、造成小鼠淋巴细胞DNA损伤,光电催化氧化降解MCLR粗提液的过程中,会产生了具有较强急性毒性的物质,使发光菌相对发光度逐渐降低,从109.6%减小为零,但这些物质不具有明显的遗传毒性,随着处理时间的延长微核率和DNA损伤水平逐渐减小,最终与阴性对照组无显著差异(P<0.05)。光电催化氧化法能够有效减小水样遗传毒性。更多还原

【Abstract】 The pollution of algal and its metabolite microcystins cause serious threats to human. The degradation of algal toxin microcystin-LR (MCLR) by photoelectrocatalytic oxidation and detoxification were studied, including anodes selection, reactor design, influence factors, and the toxicity changes during the process of photoelectrocatalytic oxidation were detected by the luminescent acute toxicity test, vicia faba root tip micronucleus method and single-cell gel electrophoresis assay, and the security of the method was discussed.The results showed that the anode materials had great influence on the degradation of MCLR and RuO2/TiO2anode had the best effect with compact surface morphology, favorable crystal form of TiO2, high oxygen evolution potential and voltammetry charge. MCLR removal rate increase form55.9%to79.6%as the increase of the number of electrode form2to6. The immersion type reactor obtained higher current efficiency of MCLR than the external radiation reactor. Besides, TiO2on the electrode surface present obvious photocatalytic effects. The degradation efficiency of photoelectrocatalytic oxidation was higher than that of the sum of photocatalytic oxidation and electrocatalytic oxidation, showing a certain synergetic effect. The best synergetic effect was obtained under optimum match condition of irradiation source and current density, which were irradiation UVC, current density10mA/cm2and irradiation UVA, current density1.0mA/cm2.The removal efficiency in photoelectrocatalytic oxidation decreased along with the increase of the plate distance, which was correlative with electrocatalytic process rather than photocatalytic process; The MCLR removal efficiency decreased with the increase of its initial concentration in photoelectrocatalytic oxidation.Crude MCLR could reduce luminosity of luminescent bacteria, induce Vicia faba root tip micronucleus and DNA damage. During photoelectrocatalytic oxidation process, some acute toxic substances were produced and led to the decrease of relative luminosity of luminescent bacteria from109.6%to zero, but those substances were not genotoxicity, as the treatment progressing, the micronucleus rate and cells DNA damage decreased, the genotoxicity of water samples showed a significantly decline (P<0.05). Photoelectrocatalytic oxidation was effective in reducing genotoxicity.更多还原