光电催化—电极生物膜体系构建及其环境应用研究

发布时间：2019-03-06 18:08

【摘要】：近年来,环境污染和能源短缺已成为制约社会发展的重要因素。本文自行设计了集成光催化法、电催化法和生物膜法的反应器,着重研究其在废水脱氮和还原溶于水中的二氧化碳为甲烷方面的应用,致力于解决环境污染和能源短缺问题。1.光催化-电极生物膜体系：将光催化法和电极生物膜法结合,利用可见光照射阳极来催化NH4+-N氧化为N2、NO3--N和NO2--N,阴极自养反硝化生物膜将水中或阳极生成的N03--N和N02--N还原为N2,实现对水中无机氮污染物的同步去除。本部分利用AgI/TiO2-NTs阳极和自养反硝化生物膜阴极构建了光催化-电极生物膜反应器,考察了反应器在不同外加电压和pH值条件下对NH4+-N、NO3--N和N02--N去除效率的影响。在最佳运行条件下(可见光照射,外加电压3V和pH值为8),NH4+-N 12 h的去除率比无光照时提升了3倍,达到71.1%；NO3--N的浓度从20 mg/L下降为5.7 mg/L,去除率为74%；NO2--N的积累量为0.6 mg/L,仅为其他条件下的50%；总氮的最大去除率达到89.6%左右。反应器表现出良好的稳定性,AgI/TiO2-NTs阳极在循环使用5次后对NH4+-N去除率仍能维持在70%左右；过程中生物膜生长良好,反硝化作用稳定,生物脱氢酶活性维持在13.Oμg/(mL·h)左右,没有出现下降趋势。2.电催化-改性电极生物膜体系：将电催化法和电极生物膜法结合,利用厌氧生物膜将溶解于水中的CO2还原为CH4,利用电极体系为生物膜还原CO2提供充足的电子促进反应进行,实现对CO2的回收、利用。本部分利用改性碳布电极和厌氧颗粒污泥构建了电催化-电极生物膜反应器,使用Cu改性生物膜电极的反应器10天的CH4积累浓度达到了14 mmol/L左右,使用Fe改性生物膜电极的反应器10天的CH4积累浓度为7 mmol/L左右,均明显高于使用普通生物膜阴极反应器的CH4积累浓度。体系运行稳定,使用Cu改性生物膜阴极的反应器中对CO2还原率为15%(12%C还原为CH4,3%C还原为甲酸、乙酸)；使用Fe改性生物膜阴极的反应器CO2还原率为12%(7%C还原为CH4,5%C还原为甲酸、乙酸)。通过对各生物膜群落多样性分析可知：电流对生物膜中群落起到筛选的作用,通电驯化下生物膜群落多样性变低,电流环境有利于生物膜中产甲烷菌生长。
[Abstract]:In recent years, environmental pollution and energy shortage have become important factors restricting social development. In this paper, an integrated photocatalysis, electrocatalysis and biofilm reactor was designed, and its application in denitrification of wastewater and reduction of carbon dioxide dissolved in water to methane was studied. To address environmental pollution and energy shortages. 1. Photocatalysis-electrode biofilm system: the photocatalysis and electrode biofilm method are combined to catalyze the oxidation of NH4-N to N _ 2, no _ 3 / N and NO2--N, by visible light-emitting anode. The cathode autotrophic denitrification biofilm reduced the N _ 0 _ 3 ~ N and N _ 2 ~ (2 +) produced in water or anode to N _ 2, and achieved the simultaneous removal of inorganic nitrogen pollutants in water. The photocatalysis-electrode biofilm reactor was constructed by using AgI/TiO2-NTs anode and autotrophic denitrification biofilm cathode. The effects of applied voltage and pH on NH4-N were investigated. The effect of NO3--N and N 02 / N removal efficiency. Under the optimum operating conditions (visible light irradiation, applied voltage of 3V and pH value of 8), the removal rate of NH4-N for 12 h was 3 times higher than that without illumination, reaching 71.1%; The concentration of NO3--N decreased from 20 mg/L to 5.7 mg/L, and the accumulation of 0.4 mg/L, was only 50% of that under other conditions, and the maximum removal rate of total nitrogen was about 89.6%. The reactor showed good stability, and the removal rate of NH4-N by AgI/TiO2-NTs anode was still about 70% after 5 cycles. The biofilm grew well and the denitrification was stable. The biodehydrogenase activity remained about 13.O渭 g / (mL 路h), and there was no decreasing trend. 2. Electrocatalysis-modified electrode biofilm system: combining electrocatalysis method with electrode biofilm method, using anaerobic biofilm to reduce CO2 dissolved in water to CH4, using electrode system to provide sufficient electron-facilitated reaction for the reduction of CO2 by biofilm. Realize the recovery and utilization of CO2. In this part, the electrocatalytic-electrode biofilm reactor was constructed using modified carbon cloth electrode and anaerobic granular sludge. The CH4 accumulation concentration of the reactor using Cu modified biofilm electrode reached about 14 mmol/L for 10 days. The accumulation concentration of CH4 in Fe modified biofilm electrode reactor for 10 days was about 7 mmol/L, which was significantly higher than that of CH4 accumulation in conventional biofilm cathode reactor. The CO2 reduction rate was 15% (12% C reduced to CH4,3%C to formic acid and acetic acid) in the reactor using Cu modified biofilm cathode. The CO2 reduction rate of Fe modified biofilm cathode was 12% (7% C reduced to CH4,5%C to formic acid and acetic acid). By analyzing the diversity of biofilm communities, we can see that current plays a role in screening the community in biofilm, and the diversity of biofilm community becomes lower under electrification, and the current environment is beneficial to the growth of methanogenic bacteria in biofilm.
【学位授予单位】：浙江工商大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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