光催化强化微生物燃料电池构建及脱氮产电效果初探

发布时间：2018-01-11 12:05

本文关键词：光催化强化微生物燃料电池构建及脱氮产电效果初探　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：氮素排放是造成水体污染的最重要原因之一。微生物燃料电池(MFCs)可以在脱氮同时产生电能,为污水脱氮提供了新思路。通过文献分析发现MFCs脱氮面临着反硝化易、硝化难的瓶颈,而污水中氮素多以氨氮的形式存在,严重制约了MFCs技术的应用。本论文针对此问题提出了光催化与MFCs的结合技术,制作了光催化强化微生物燃料电池(Photo-MFCs),采用p、n型两种光催化剂实现光生电子和空穴的分离和富集,利用光生空穴的强氧化性加强MFCs阳极室的硝化效果,利用光生电子的强还原性加强MFCs阴极室的反硝化效果,从而解决MFCs硝化难的问题。同时,Photo-MFCs还能将MFCs脱氮反应与产电过程耦合,从而提高MFCs产电能力。论文在以有机物和氨氮作为混合基质和氨氮为单一基质条件下,分别研究了有机物、氨氮和硝态氮对Photo-MFCs脱氮和产电的影响;论文还研究了光催化对Photo-MFCs脱氮和产电的强化作用,并分析了Photo-MFCs中氮素的迁移转化途径以及电子传递过程,得到以下主要结论:①以有机物和氨氮为混合基质时,降低有机物的浓度,Photo-MFCs脱氮和产电效果都有所下降。当水力停留时间为12h,进水有机物浓度从122±2.8mg/L降低至0mg/L时,Photo-MFCs总氮的去除率降低了2.74倍,最高电流产生量由1.06m A降低为0.16m A。较低的有机物浓度有利于阳极室氨氮的硝化,当系统中不存在有机物时,阳极室氨氮的去除量从6.3±2.70mg/L增加到11.5±0.70mg/L,硝态氮的累积量从-0.7±1mg/L增加到6.7±0.7mg/L。②以氨氮作为唯一基质时,Photo-MFCs仍然能实现脱氮和产电,且氨氮浓度对Photo-MFCs脱氮和产电效果起主要作用,硝态氮浓度对系统总氮去除量和产电性能无显著影响。随着阳极室进水氨氮浓度的增加,Photo-MFCs脱氮和产电效果先增加后降低。当氨氮浓度为70mg/L时,Photo-MFCs脱氮和产电效果最好,12h内阳极室内氨氮的去除量达到19.3mg/L,硝态氮的累积量达到15.41mg/L;阴极室内硝态氮和总氮的去除量分别为22.3mg/L和17.1mg/L;Photo-MFCs最大电流为0.042m A,最大功率密度为3.68μW/m2。③当氨氮作为唯一基质时,Photo-MFCs阳极室去除的氨氮中62.6%转化为硝态氮,7%转化为亚硝态氮,0.9%扩散到了阴极室,其它部分的可能挥发至大气或被微生物同化吸收。阴极室中被去除的硝态氮主要被还原为氮气,有少量亚硝态氮累积。④光照有助于提升Photo-MFCs的脱氮和产电效果。在紫外光照射下,12h内Photo-MFCs阳极室内氨氮的平均硝化速率由0.58mg/(L·h)增加至1.34 mg/(L·h),阴极室反硝化速率由0.5mg/(L·h)增加至1.2mg/(L·h),平均产电量也由0.012m A增加至0.032m A。光照可增加电极的氧化还原性,有助于硝化和反硝化反应的发生。在光照时微生物燃料电池两极电势差由20m V增加到了72m V。光照过程中电子的传递过程为:氨氮→硝化细菌→n型半导体→p型半导体→反硝化细菌→硝酸盐→氮气。
[Abstract]:Nitrogen emission is one of the most important cause of the water pollution. Microbial fuel cell (MFCs) can also generate electricity in nitrogen removal, provides a new way for nitrogen removal from wastewater. Through the analysis we found MFCs denitrification facing denitrification, nitrification bottleneck difficult, and sewage in nitrogen in the form of ammonia there, seriously restricts the application of MFCs technology. This paper puts forward technology combined with photocatalysis and MFCs, making the enhanced photocatalytic microbial fuel cell (Photo-MFCs), using P, n two photocatalyst for photoinduced electron hole separation and enrichment, nitrification using strong oxidation photohole strengthen MFCs anode chamber, denitrification effect reduction by strengthening MFCs cathode chamber electron strong, so as to solve the difficult problem of nitration of MFCs. At the same time, Photo-MFCs can MFCs denitrification reaction process coupling and electricity production, from To improve the output power of MFCs. Based on the organic matter and ammonia nitrogen as ammonia mixed into a single matrix and matrix under the conditions of organic matter were studied, effects of ammonia and nitrate nitrogen of Photo-MFCs and electricity production; the paper also studies the photocatalysis of Photo-MFCs nitrogen removal and electricity production strengthening effect, and analysis of the way and the process of electron transfer in Photo-MFCs migration and transformation of nitrogen, the main conclusions are as follows: 1 with organics and ammonia as the mixed matrix, reduce the concentration of organics, nitrogen and Photo-MFCs generate electricity are decreased. When the HRT is 12h and the influent organic concentration decreased from 122 to 2.8mg/L. 0mg/L, the total nitrogen removal rate of Photo-MFCs decreased by 2.74 times, the highest current generated by the 1.06M A 0.16m A. is reduced to lower the concentration of organic matter to the anode chamber nitrification of ammonia, when organic matter does not exist in the system, Yang The amount of ammonia nitrogen removal chamber increased from 6.3 + 2.70mg/L to 11.5 + 0.70mg/L, increase the accumulation of nitrate nitrogen from -0.7 + 1mg/L to 6.7 + 0.7mg/L. 2 with ammonia as the sole substrate, Photo-MFCs can still achieve nitrogen and electricity production, and ammonia concentration on nitrogen removal in Photo-MFCs and the effect of producing electricity plays a main role. No significant influence of the concentration of nitrate nitrogen removal of total nitrogen and electricity production performance. With the increase of the anode chamber of influent ammonia concentration, Photo-MFCs nitrogen removal and the effect of producing electricity increases first and then decreases. When ammonia concentration is 70mg/L, the best Photo-MFCs nitrogen and the effect of producing electricity, removal rate of ammonia nitrogen reached 12h in the anode chamber 19.3mg/L, the accumulation of nitrate nitrogen removal in the cathode chamber reaches 15.41mg/L; nitrate nitrogen and total nitrogen were 22.3mg/L and 17.1mg/L respectively; Photo-MFCs 0.042m maximum current of A, the maximum power density of 3.68 W/m2. when the ammonia as the sole substrate, The 62.6% is transformed into nitrate nitrogen in ammonia nitrogen removal of the anode chamber Photo-MFCs, 7% converted to nitrite, 0.9% spread to other parts of the cathode chamber to the atmosphere may volatile or absorbed by microbial assimilation. Nitrate nitrogen was removed mainly by reduction of nitrogen in the cathode chamber, a small amount of nitrite nitrogen accumulation. The light will help improve Photo-MFCs denitrification and the effect of producing electricity. Under UV irradiation, the average nitrification rate of 12h Photo-MFCs in the anode chamber of ammonia nitrogen by 0.58mg/ (L h) increased to 1.34 mg/ (L - H), the cathode chamber denitrification rate by 0.5mg/ (L h) increased to 1.2mg/ (L - H), the average amount of electricity produced by the 0.012m A 0.032m A. to increase light can increase the electrode oxidation, contribute to nitrification and denitrification. In the light poles of potential microbial fuel cell by 20m V to the 72m V. light in the process of electron transfer process for ammonia: Nitrifying bacteria, N type semiconductors, P type semiconductors, denitrifying bacteria, nitrate, and nitrogen.

【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;TM911.45

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