生物阴极双室微生物燃料电池同步除碳脱氮与产电特性研究

发布时间：2018-06-27 21:41

本文选题：微生物燃料电池 + 生物阴极　；参考：《东华大学》2014年硕士论文

【摘要】：微生物燃料电池(MFC)以电极表面的功能微生物为催化剂,使阳极在低电势下氧化有机物,阴极在高电势还原电子受体,通过电子和质子的定向迁移在回路中形成电流。为了克服传统化学阴极MFC需要利用贵金属等催化剂在阴极进行氧气还原以及由于阳离子交换膜(CEM)选择透过性缺陷造成的阴极pH升高,本研究将硝化引入MFC阴极室,构建生物阴极双室微生物燃料电池。通过阴极室的筛选培养,实现用功能微生物替代传统重金属等作催化剂,利用硝化需好氧环境以及产生质子的特点,在阴极实现还原氧气产电和NH4+-N到N03--N的转化,避免阴极室pH升高对阴极微生物的代谢产生影响。首先,为了考察有机碳源对MFC阴极室微生物的影响,在完全自养(不投加有机碳源)和COD:N=1.7:1条件下,研究了硝化细菌的生长规律。结果表明,驯化后两种运行方式的硝化率均能达到99%以上,但在不同时期趋势却有所不同。两个反应器中亚硝酸细菌和硝酸细菌个数分别达到了2.5×106、4.5×104和2×106、7.5×l04cfu/mL,处于同一数量级上。然而由于1号反应器碳源的单一性,使其污泥浓度逐渐减小,而2号反应器相应值则逐渐增加。SEM表明两池在培养末期均有杆菌、球菌等的出现。在COD:N=1.7:1下,系统更易保持稳定性。同时,为了降低构建MFC的成本,比较了以碳毡和碳布作为阴极材料,在阴极利用功能微生物作为催化剂时电池的产电性能。结果表明,两电池启动时间基本相同,20d左右达到稳定,但稳定期碳布作阴极的电池电压比碳毡作阴极的电池电压高出了60mV左右。碳毡和碳布作阴极时,电池在10d和20d的最大功率密度分别由10.24、11.14mW/m2提升到了18.18、30.15mW/m2,相应内阻则分别由1000、600Ω降到了250、200Ω。扫描电镜(SEM)观察到两者不同表面特性导致碳毡对污泥附着强于碳布,进而使氧气传递受到限制,产电降低。接着,基于启动阶段的结果,选择碳布作为阴极材料,进行了MFC同步除碳、脱氮及产电的研究。分别研究了不同阳极进水COD、不同阴极进水氨氮、不同阴极室溶解氧(DO)对MFC产电及污染物去除的影响以及硝化在阴极室的作用。研究表明,在阳极进水COD为100、400、700、1000mg/L时,电池稳定期持续时间和电压逐渐升高,分别为10、50、60、90h以及136.4、145.7、164.9、190.1mV, COD去除率从74.85%上升到了89.89%,但库伦效率从7.15%下降到了5.66%。在阳极进水COD=700mg/L,阴极室DO=4mg/L时,随着阴极进水氨氮浓度的增加(40、80、120mg/L),氨氮去除速率有较大差别,在前24h分别为27、36.2、51.1mg/(L·d),但对电池产电无较大影响,稳定期电压相差不大,分别为165、177、194mV,表现出了一定适应性。在阳极进水COD=700mg/L,阴极进水氨氮浓度为80mg/L时,随着DO从2mg/L增加到4mg/L,72h氨氮降解速率基本相同,但电池产电性能逐渐提高,12h开路电压分别为556.8、592.1、597mV,最大功率密度分别为31、52.9、75.2mW/m2,平均电压分别为139、161、178mV左右。在硝化作用的研究中,发现阴极进水氨氮浓度为20mg/L时,阴极pH在前2h从7.15升高到7.62,但在硝化影响下后又逐渐降低并稳定在6.86,而进水中无氨氮时,阴极pH在前2h从7.58迅速上升到了8.62,而且后期无明显变化。最后分析了运行5个月的碳布阴极MFC微生物种群结构。用聚合酶链式反应(PCR)、变性梯度凝胶电泳(DGGE)技术对其中的细菌群落分布进行了研究。研究表明碳布阴极MFC阳极微生物菌属主要是Acinetobacter sp.、 Treponema、Pseudomonas saccharophila、 uncultured Anaerovorax sp.;阴极主要是Sediminibacterium、Treponema、 Pedobacter heparinus、uncultured Anaerovorax sp、Bartonella tamiae。其中Pseudomonas sp.、cinetobacter sp.为常见的阳极微生物产电菌。
[Abstract]:A microbial fuel cell (MFC) uses functional microbes on the surface of the electrode as a catalyst to oxidize the organic matter under the low potential of the anode. The cathode reduces the electron acceptor at a high potential and forms a current in the loop through the directional migration of electrons and protons. In order to overcome the traditional chemical cathode MFC, a catalyst such as precious metals should be used to carry oxygen to the cathode. Reduction and the increase of cathode pH caused by selective permeability defect of cation exchange membrane (CEM). In this study, nitrification was introduced into the MFC cathode chamber to construct a biocathode double chamber microbial fuel cell. Through screening and culture of the cathode chamber, the functional microorganism was used as a catalyst to replace the traditional heavy metals, and the aerobic environment and production were produced by nitrification. The characteristics of proton generation are the reduction of oxygen production and the conversion of NH4+-N to N03--N in the cathode. The increase of pH in cathode chamber will have an effect on the metabolism of cathode microorganisms.
First, in order to investigate the effect of organic carbon source on the microorganism of the MFC cathode chamber, the growth regularity of nitrifying bacteria was studied under the condition of complete autotrophic (not adding organic carbon source) and COD:N=1.7:1. The results showed that the nitrification rate of two operating modes after domestication could reach more than 99%, but the trend in different periods was different. Two reactors in Central Asia. The number of nitrate bacteria and nitrate bacteria reached 2.5 * 106,4.5 * 104 and 2 x 106,7.5 x l04cfu/mL, at the same order of magnitude. However, because of the single carbon source of the No. 1 reactor, the sludge concentration gradually decreased, while the corresponding value of the 2 reactor increased gradually by.SEM indicating that the two pool appeared at the end of the culture and appeared in COD. Under N=1.7:1, the system is more stable. At the same time, in order to reduce the cost of building MFC, the electric performance of the battery is compared with the carbon felt and carbon cloth as the cathode material and the cathode using the functional microorganism as the catalyst. The results show that the starting time of the two battery is basically the same, the 20d is stable, but the stable carbon cloth is used as the cathode battery. The voltage of the cell voltage is about 60mV higher than that of the carbon felt as the cathode. When the carbon felt and carbon cloth are used as the cathode, the maximum power density of the 10d and 20d increases from 10.24,11.14mW/m2 to 18.18,30.15mW/m2, respectively, and the corresponding internal resistance is reduced from 1000600 Omega to 250200 Omega respectively. The scanning electron microscope (SEM) observed that the different surface characteristics lead to the carbon felt pairs. Sludge adhesion is stronger than that of carbon cloth, which limits oxygen production and reduces electricity production.
Then, based on the results of the start-up phase, the carbon cloth was selected as the cathode material, and the simultaneous removal of carbon, nitrogen and electricity in MFC was carried out. The effects of different anode influent COD, different cathode influent ammonia nitrogen, different cathode chamber dissolved oxygen (DO) on the production of MFC and the removal of pollutants and the effect of Nitrification on the cathode chamber were studied. When the extreme influent COD is 1004007001000mg/L, the duration and voltage of the battery stability increase gradually, 10,50,60,90h and 136.4145.7164.9190.1mV respectively. The removal rate of COD increases from 74.85% to 89.89%, but the efficiency of Kulun decreases from 7.15% to 5.66%. in the anode influent COD=700mg/L, the cathode chamber DO=4mg/L, with the cathodic influent ammonia nitrogen concentration. The increase (40,80120mg/L), the removal rate of ammonia nitrogen is very different, the former 24h is 27,36.2,51.1mg/ (L. D), but it has no big effect on the battery production, and the voltage of the stable phase is not very different, and it is 165177194mV, respectively, which shows certain adaptability. When the anode influent COD= 700mg/L, the concentration of the ammonia nitrogen in the cathode is 80mg/L, as DO increases from 2mg/L to 2mg/L. 4mg/L, 72h ammonia nitrogen degradation rate is basically the same, but the battery production performance increases gradually, 12h open circuit voltage is 556.8592.1597mV, the maximum power density is 31,52.9,75.2mW/m2, the average voltage is about 139161178mV respectively. In the study of nitrification, it was found that when the concentration of ammonia nitrogen was 20mg/L, the cathode pH was in the front 2H from 7. .15 increased to 7.62, but gradually decreased and stabilized at 6.86 after nitrification, while the cathode pH increased rapidly from 7.58 to 8.62 in the former 2h, and there was no obvious change in the later period.
Finally, the microorganism population structure of the carbon cathode MFC was analyzed for 5 months. The bacterial community distribution was studied by polymerase chain reaction (PCR) and denaturalization gradient gel electrophoresis (DGGE). The study showed that the microorganism of the carbon cathode MFC anode was mainly Acinetobacter sp., Treponema, Pseudomonas saccharophila, uncult. Ured Anaerovorax sp.; the cathode is mainly Sediminibacterium, Treponema, Pedobacter heparinus, uncultured Anaerovorax SP, Bartonella tamiae., which is a common anode microorganism producing bacteria.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.45;X703

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