微生物燃料电池同步脱氮产电性能及机理研究

发布时间：2018-06-02 02:28

本文选题：微生物燃料电池 + 反硝化　；参考：《浙江大学》2014年博士论文

【摘要】：面对环境污染和能源短缺的双重压力,传统高能耗的废水处理技术已难以满足可持续发展的要求。微生物燃料电池(Microbial fuel cell, MFC)以微生物为催化剂将废水中污染物蕴含的化学能直接转化为电能,可实现同步治污产电。但迄今为止,MFC研究主要集中在有机废水方面。在氮素污染凸现的今天,研发兼具脱氮产电功能的MFC对废水处理具有重大的现实意义。本文创建阳极反硝化微生物燃料电池(Anodic denitrification MFC, AD-MFC)和厌氧氨氧化微生物燃料电池(Anaerobic ammonium oxidation MFC, ANAMMOX-MFC),系统而深入地研究了AD-MFC和ANAMMOX-MFC的脱氮产电性能、影响因素和工作机理,主要结果如下： 1)创建了AD-MFC,探明了其同步反硝化产电性能。以反硝化菌富集培养物为生物催化剂,成功创建AD-MFC,实现了同步反硝化产电。AD-MFC具有良好的脱氮产电性能。在批式试验中,初始硝氮浓度和COD浓度分别为100.22±0.62mg/L和500.40±1.67mg/L, AD-MFC的最大容积反硝化速率、最大电压和最大功率密度分别达到0.31±0.01kgN/m3·d、602.80±5.42mV和908.42±0.07mW/m3。AD-MFC的产电过程呈现阶段性变化。由于阳极液中主导反应(反硝化、甲醇降解、内源呼吸和细胞水解发酵)依次演替,阳极电极电势不断变化,导致电压曲线呈现“降低-升高-再降低”的三阶段过程特性,未见国内外相关文献报道。AD-MFC蕴藏指示功能。硝氮消耗、COD消耗与电压损耗的Pearson相关系数分别达到0.9964和0.9917,电压变化与反硝化基质浓度变化呈显著线性相关,电信号可指示反硝化进程。 2)考察了基质浓度对AD-MFC脱氮产电性能的影响,揭示了AD-MFC污染物降解和产电动力学规律。 AD-MFC脱氮产电性能与基质浓度密切相关。在低浓度范围,提高基质浓度可提高微生物活性,强化AD-MFC脱氮产电能力,但在高基质浓度范围,基质产生自抑制,削弱AD-MFC脱氮产电能力。AD-MFC基质降解和产电动力学过程符合Han-Levenspiel模型。以该模型拟合得到的NO3-N降解、COD降解、输出电压、功率密度的最大值(rmax)、半饱和常数(Ks)和完全抑制浓度(Sm)分别为1.27kg N/m3·d.351.63mg/L和4301.25mg/L;5.14kgCOD/m3·d.1950.21mg/L和20050.69mg/L;1030.53mV.203.25mg/L和4950.36mg/L;1386.39mW/m3、293.47mg/L和4649.03mg/L。NO3--N半饱和常数(Ks)大于200mg NO3--N/L,完全抑制浓度(Sm)大于4000mg NO3--N/L,表明AD-MFC对高基质浓度具有较强的耐受性。AD-MFC适用于高浓度硝酸盐有机废水的除污和产电。初始NO3-N浓度和COD浓度分别为1999.95±2.86mg/L和10058±1.26mg/L时,最大反硝化速率、最大电压和最大功率密度分别达1.26±0.01kg N/m3·d、1016.75±4.74mV和1314.41±24.60mW/m3.其容积脱氮速率处于国内外文献报道的较高水平。 3)分析了AD-MFC物质转化特性、微生物功能空间分布、电子传递机制和功能菌群组成,揭示了AD-MFC工作机理。 AD-MFC产电过程与反硝化相耦合。单独以甲醇或硝酸盐作为基质时,两者不能被有效降解,AD-MFC产电能力也有限；只有当两者共存时,AD-MFC才能发挥脱氮产电效能。阳极上的生物膜和阳极液中的悬浮污泥均具有脱氮产电功能,其功能空间小于AD-MFC的总体功能空间,AD-MFC反硝化脱氮过程由电极生物膜和悬浮污泥协作完成。电极生物膜和悬浮污泥的反硝化功能空间分别为41.90%和67.98%,产电功能空间分别为52.26%和69.03%,悬浮污泥在AD-MFC功能空间中占据优势。电极生物膜和悬浮污泥具有不同的电子传递机制。电极生物膜主要依靠直接接触的方式进行电子传递；而悬浮污泥在不同反应阶段可产生多种中介体,主要依靠中介体为媒介进行电子传递。AD-MFC中功能菌群组成差异较大。接种污泥含有大量的球菌、杆菌和丝状菌,而电极生物膜主要为丝状菌和杆菌,悬浮污泥主要为球菌和丝状菌。菌群结构随产电过程发生演替,悬浮污泥和电极生物膜中微生物种类较接种污泥明显减少。AD-MFC中的优势菌群归属于γ-变形菌纲、p-变形菌纲、拟杆菌纲和Ignavibacteria纲,功能菌群主要为反硝化菌。 4)创建了ANAMMOX-MFC,探明了其同步厌氧氨氧化产电性能。以ANAMMOX菌富集培养物作为生物催化剂,成功创建ANAMMOX-MFC,实现了同步厌氧氨氧化产电。ANAMMOX-MFC具有良好的脱氮产龟性能。在连续试验中,进水NH4+-N和N02--N浓度分别从25mg/L和33mg/L逐渐提升至250mg/L和330mg/L时,NH4+-N、 NO2--N和TN去除率分别保持在90%、90%和80%以上,容积脱氮速率最大可达3.01±0.27kg N/m3·d,最大电压和最大功率密度可达225.48±10.71mV和1308.23±40.38mW/m3,是目前文献报道的最高MFC脱氮负荷。ANAMMOX-MFC阳极极化显著,阳极电荷传递电阻约占ANAMMOX-MFC总电阻的60%,是限制ANAMMOX-MFC产电的瓶颈因素。ANAMMOX-MFC也蕴含指示功能。在一定范围内(25mg/L～250mg/L),输出电压随进水NH4+-N浓度线性变化,可以指示NH4+-N浓度,这种指示功能主要来自于不同NH4+-N浓度所致的氨氧化速率变化。 5)考察了温度、pH和中介体对ANAMMOX-MFC脱氮产电性能的影响,优化了ANAMMOX-MFC的操作条件。温度可显著影响ANAMMOX-MFC的脱氮产电性能。ANAMMOX-MFC脱氮产电的最适温度约为30℃；高于或低于此温度时,容积脱氮速率和输出电压同步降低；温度变化引起生物反应变化是导致ANAMOX-MFC产电性能变化的主要原因。pH也可影响ANAMMOX-MFC的脱氮产电性能。ANAMMOX-MFC脱氮产电的最适pH为7～8；pH影响ANAMMOX-MFC容积脱氮速率和输出电压的同步性较低；pH所致的生物反应变化和阳极电极电势变化共同引发了ANAMMOX-MFC产电性能变化。中介体可强化ANAMMOX-MFC产电性能。低浓度(0.01mmol/L)的中性红、2-羟基-1,4-萘醌和吩噻嗪等对应电子传递链前端、分子量较小、结构简单的中介体,可有效降低阳极电荷转移电阻,显著强化ANAMMOX-MFC产电性能；而灿烂甲酚蓝和血红素等对应电子传递链后端、分子量较大、结构相对复杂的中介体,对ANAMMOX-MFC产电性能的强化作用较弱；中介体浓度过高(0.01～0.02mmol/L)会抑制生物反应,致使ANAMMOX-MFC产电能力不升反降。 6)研究了ANAMMOX-MFC的物质转化特性、功能菌群组成、微生物功能空间分布和电子传递机制,揭示了ANAMMOX-MFC工作机理。 ANAMMOX-MFC产电过程与ANAMMOX反应相耦合。单独以氨或亚硝酸盐作为基质时,ANAMMOX菌富集培养物发生水解,脱氮产电过程无法维持；氨氧化与亚硝酸盐还原相耦合,只有当氨和亚硝酸盐共同作为产电基质时,ANAMMOX-MFC才能持续发挥脱氮产电功能。阳极上的生物膜和阳极液中的悬浮污泥均具有同步厌氧氨氧化产电功能,ANAMMOX-MFC脱氮产电过程也由电极生物膜和悬浮污泥协同完成。ANAMMOX-MFC中电极生物膜和悬浮污泥分别在不同的功能空间中占据优势,电极生物膜和悬浮污泥的厌氧氨氧化功能空间分别为30.14%和53.43%,产电功能空间分别为59.52%和47.87%。电极生物膜和悬浮污泥具有不同的电子传递机制。电极生物膜主要依靠直接接触方式进行电子传递；而悬浮污泥主要依靠中介体为媒介进行电子传递,基质中的NO2-N组分可作为潜在的中介体,悬浮污泥自身也可产生中介体。ANAMMOX-MFC中的功能菌群组成存在一定差异。电极生物膜上的ANAMMOX菌厌氧氨氧化体更大,铁颗粒数量较多,血红素c含量较高,胞外多聚物(Extracellular polymeric substances,EPS)含量较少,有助于增强胞外电子传递能力。悬浮污泥中的微生物种类与接种污泥类似,而电极生物膜中的微生物种类与接种污泥差异较大。ANAMMOX-MFC中的优势菌群归属于p-变形菌纲、γ-变形菌纲、酸杆菌纲、Ignavibacteria纲和浮霉状菌门,功能菌群是由ANAMMOX菌、反硝化细菌和其他多种细菌组成的共生体系。
[Abstract]:In the face of the dual pressure of environmental pollution and energy shortage, the traditional high energy waste water treatment technology has been difficult to meet the requirements of sustainable development. Microbial fuel cell (MFC) uses microorganism as the catalyst to convert the chemical energy contained in the wastewater directly into electric energy, and can achieve synchronous pollution control and produce electricity. MFC research is mainly focused on organic wastewater. In the present situation of nitrogen pollution, it is of great practical significance to research and develop MFC with the function of denitrification and electricity production for wastewater treatment.
In this paper, an anodic denitrifying microbial fuel cell (Anodic denitrification MFC, AD-MFC) and an anaerobic ammoxidation microbial fuel cell (Anaerobic ammonium oxidation MFC, ANAMMOX-MFC) are established. The performance, influence factors and working mechanism of AD-MFC and ANAMMOX-MFC are systematically studied. The main results are as follows:
1) AD-MFC was established to verify its synchronous denitrification power generation performance.
The AD-MFC was successfully created with the enrichment of the denitrifying bacteria as a biocatalyst, and the simultaneous denitrification and electricity production of.AD-MFC was achieved. In the batch test, the initial Nitron concentration and COD concentration were 100.22 + 0.62mg/L and 500.40 + 1.67mg/L respectively, the maximum denitrification rate of AD-MFC, the maximum voltage and maximum power The production process of the density of 0.31 + 0.01kgN/m3. D, 602.80 + 5.42mV and 908.42 + 0.07mW/m3.AD-MFC showed a phased change. Due to the leading reaction in the anode (denitrification, methanol degradation, endogenous respiration and cell hydrolysis fermentation) successively successional succession, the anode electrode potential changed continuously, resulting in the voltage curve showing "decrease - rise - then decrease" The characteristics of the three stage process have not been reported in the domestic and foreign related literature on the.AD-MFC implication function. Nitrate consumption, the Pearson correlation coefficient of COD consumption and voltage loss are 0.9964 and 0.9917 respectively, and the voltage changes have a significant linear correlation with the change of denitrification matrix concentration, and the electrical signals can indicate the denitrification process.
2) the effect of substrate concentration on AD-MFC denitrification and electricity generation was investigated, and the degradation and electrokinetics of AD-MFC pollutants were revealed.
The performance of AD-MFC denitrification is closely related to the matrix concentration. In the low concentration range, the increase of substrate concentration can increase the activity of microorganism and strengthen the capacity of AD-MFC removal of nitrogen, but at the high matrix concentration, the matrix produces self inhibition, and the capacity of AD-MFC denitrification is weakened, and the degradation of.AD-MFC matrix and the electrokinetic process are in accordance with the Han-Levenspiel model. The NO3-N degradation, COD degradation, the maximum output voltage, the maximum power density (Rmax), the semi saturation constant (Ks) and the total inhibitory concentration (Sm) are 1.27kg N/m3. D.351.63mg/L and 4301.25mg/L respectively, and 5.14kgCOD/m3. D.1950.21mg/L and 20050.69mg/L. The NO3--N semi saturation constant (Ks) is larger than 200mg NO3--N/L, and the total inhibitory concentration (Sm) is greater than 4000mg NO3--N/L. It shows that AD-MFC has strong tolerance to high matrix concentration and is suitable for the removal of pollution and electricity production in high concentration nitrate organic wastewater. The initial NO3-N concentration and COD concentration are divided into 1999.95 + 2.86mg/L and 10058 +. The rate, maximum voltage and maximum power density are 1.26 + 0.01kg N/m3. D, 1016.75 + 4.74mV and 1314.41 + 24.60mW/m3., and their volumetric denitrification rates are at higher levels reported in the literature at home and abroad.
3) the transformation characteristics of AD-MFC substance, the spatial distribution of microbial function, the mechanism of electron transport and the composition of functional flora were analyzed, and the working mechanism of AD-MFC was revealed.
The AD-MFC production process is coupled with the denitrification phase. When methanol or nitrate is used as the substrate, both can not be effectively degraded and the capacity of AD-MFC production is limited. Only when both coexist, AD-MFC can exert the efficiency of nitrogen removal and production. The biofilm and the suspended sludge on the anode have the function of denitrification and electricity production, and its function space Less than AD-MFC's overall function space, AD-MFC denitrification process is completed by electrode biofilm and suspended sludge. The denitrification function space of electrode biofilm and suspended sludge is 41.90% and 67.98% respectively, and the function space of electricity production is 52.26% and 69.03% respectively. The suspended sludge occupies the advantage in AD-MFC function space. Electrode biofilm and suspension The floating sludge has different electron transfer mechanisms. The electrode biofilm mainly relies on direct contact, while the suspended sludge can produce a variety of intermediaries in the different reaction stages, mainly depending on the mediator as the medium for the electronic transfer of functional bacteria in.AD-MFC, and the inoculated sludge contains a large number of cocci and rods. Bacteria and filamentous bacteria, and electrode biofilm mainly filamentous bacteria and bacilli, suspended sludge is mainly cocci and filamentous bacteria. The structure of the bacteria group is successional with the process of electricity production. The microbial species in the suspended sludge and electrode biomembrane are obviously less than the inoculated sludge. The dominant bacteria in.AD-MFC belong to gamma deforminum, p- Proteus, bacteriobacteria and Ig Navibacteria class, the functional flora is mainly denitrifying bacteria.
4) ANAMMOX-MFC was established, and its synchronous anammox power generation performance was proved.
ANAMMOX-MFC was successfully created with the enrichment culture of ANAMMOX bacteria as a biocatalyst. The performance of nitrogen producing tortoise with synchronous anaerobic ammonia oxidation production.ANAMMOX-MFC was achieved. In continuous experiments, when the concentration of influent NH4+-N and N02--N gradually increased from 25mg/L and 33mg/L to 250mg/L and 330mg/L, NH4+-N, NO2--N and TN removal rates were guaranteed respectively. The maximum volumetric denitrification rate is up to 3.01 + 0.27kg N/m3 d at 90%, 90% and 80%. The maximum voltage and maximum power density can reach 225.48 + 10.71mV and 1308.23 + 40.38mW/m3. The highest MFC denitrogenation load of the current literature is.ANAMMOX-MFC anode polarization significant, and the anode charge transmission resistance accounts for 60% of the total ANAMMOX-MFC resistance, which is limited ANA. The bottleneck factor of MMOX-MFC production.ANAMMOX-MFC also contains indicator function. In a certain range (25mg/L to 250mg/L), the output voltage varies linearly with the concentration of the influent NH4+-N, which can indicate the concentration of NH4+-N. This indicator function mainly comes from the change of the rate of ammoxidation caused by different NH4+-N concentrations.
5) the effects of temperature, pH and intermediaries on the nitrogen and nitrogen generation of ANAMMOX-MFC were investigated, and the operating conditions of ANAMMOX-MFC were optimized.
The temperature can significantly affect the performance of nitrogen and electricity of ANAMMOX-MFC, the optimum temperature of.ANAMMOX-MFC is about 30 C. When the temperature is above or below the temperature, the volume denitrification rate and the output voltage synchronously decrease, and the change of the temperature caused by the change of the biological reaction is the main cause of the transformation of the electrical property of ANAMOX-MFC, and the.PH can also affect the ANAMMOX-MFC. The optimum pH for denitrification and production of nitrogen and electricity by.ANAMMOX-MFC is 7~8, and the synchronization of ANAMMOX-MFC volume denitrogenation rate and output voltage is lower by pH; the changes of biological reaction and anode electrode potential caused by pH lead to the change of electrical property of ANAMMOX-MFC. The medium can strengthen the property of ANAMMOX-MFC production and low concentration (0.01mmol/). The neutral red, 2- hydroxy -1,4- naphthoquinone and phenothiazine, which correspond to the front-end of the electron transfer chain, have a small molecular weight and a simple structure, which can effectively reduce the anode charge transfer resistance and significantly enhance the property of the ANAMMOX-MFC production, while the back end of the electron transfer chain, such as brilliant Cresol Blue and heme, is larger, and the structure is relatively complex. The medium, which has a weak strengthening effect on the electrical properties of ANAMMOX-MFC, is too high (0.01 ~ 0.02mmol/L) to inhibit the biological reaction, which causes the power production capacity of ANAMMOX-MFC to decrease and reverse.
6) we studied the material transformation characteristics of ANAMMOX-MFC, the composition of functional flora, the spatial distribution of microbial function and the mechanism of electron transport, and revealed the working mechanism of ANAMMOX-MFC.
The ANAMMOX-MFC production process is coupled with the ANAMMOX reaction. When ammonia or nitrite is used as the substrate, the enrichment culture of ANAMMOX bacteria is hydrolyzed and the process of nitrogen removal is not maintained; the ammonia oxidation and nitrite reduction are coupled. Only when the ammonia and nitrite are used as the substrate for the production of electricity, the ANAMMOX-MFC can continue to play the power of denitrification and production. Function. Both the biofilm on the anode and the suspended sludge in the anodic liquid have the function of synchronous anammox production. The process of ANAMMOX-MFC denitrification and electricity production is also accomplished by the synergistic completion of electrode biological membrane and suspended sludge in the.ANAMMOX-MFC electrode biofilm and suspended sludge in different functional spaces, electrode biofilm and suspended sludge. The function space of anammox is 30.14% and 53.43%, respectively, and the function space of the electricity is 59.52% and the 47.87%. electrode biofilm and the suspended sludge have different electron transfer mechanism. The electrode biofilm mainly relies on the direct contact mode to carry on the electron transfer, and the suspended sludge is mainly mediated by the medium by the medium. The NO2-N components in the medium can also be used as potential intermediaries, and the suspended sludge itself can also produce a certain difference in the composition of functional bacteria in the intermediary.ANAMMOX-MFC. The anaerobic ammonia oxidizing body of ANAMMOX bacteria on the electrode biofilm is larger, the amount of iron particles is more, the content of heme C is higher, and the extracellular polymer (Extracellular polymeric substances, EPS) is contained. The amount of the microorganism in the suspended sludge is similar to the inoculated sludge, while the species in the biofilm of the electrode biological membrane are different from the inoculated sludge, and the dominant bacteria in the.ANAMMOX-MFC are attributed to the p- Proteus, the gamma deforma, the acid phylum, the Ignavibacteria class and the floating mycophenolate, and the functional bacteria. The group is a symbiotic system composed of ANAMMOX bacteria, denitrifying bacteria and many other bacteria.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：X703;TM911.45

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