生物阴极微生物脱盐燃料电池驱动电容法深度除盐性能研究

发布时间：2018-03-21 14:35

本文选题：微生物脱盐燃料电池　切入点：生物阴极　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：自从1980年之后,全球范围内的海水淡化装机容量大幅度上升,海水淡化规模以每年最高30%的速度在增长。在使用海水淡化增加饮用水的同时,能源的消耗巨大,在最近建设的反渗透海水淡化厂中,能量的消耗大约为3到4 k Wh/m3,能源的短缺及过高的运行成本,限制了其广泛应用。特别是对于远离陆地的海岛及长期海上作业的轮船等特殊环境,由于没有足够的电能而无法从海水中获得淡水。2009年,微生物脱盐燃料电池(Microbial desalination cell,MDC)的提出使得在不消耗电能的情况下实现海水淡化成为可能。经过5年多的研究,MDC技术虽然在脱盐效率上有所提高,但是由于MDC阴极中仍使用难以循环利用的铁氰化钾溶液或昂贵的铂(Pt)做催化剂的空气阴极,限制了MDC的扩大化、降低了实际应用的可能性。在MDC脱盐过程中,随着脱盐室盐浓度的降低,其系统的内阻导致脱盐效率的显著下降,这方面的特性也使得MDC不适用于低浓度含盐水,难以将海水脱盐到可饮用的标准。针对以上问题,本研究在开发廉价可持续性催化剂、MDC与其他技术耦合深度脱盐等方面做了系统性研究。提出了以同步脱盐、产电为目的的生物阴极MDC;并将生物阴极MDC产生的电能用于驱动膜电容脱盐技术(Membrane capacitive deionization,MCDI)进行深度脱盐。为MDC低成本应用于海水除盐获得淡水方面提供新思路。开发了以微生物作为阴极催化剂的空气阴极MDC。与不添加微生物作为催化剂的曝气阴极相比,MDC阴极电极表面生长的生物膜能够降低阴极的内阻、提高MDC的输出电压和输出功率,从而提高了MDC的脱盐速率。运行稳定后在1000Ω外电阻条件下的最高电压可达570 m V,对于初始浓度为35 g/L的模拟海水,经过480 h的运行后,盐浓度最低可以降到1 g/L以下,去除率可达90%以上。但随着盐水浓度的降低,脱盐速率大幅度下降,对于1 g/L以下的盐溶液,脱盐速率只有35 g/L时的16%。MDC脱盐室内盐溶液浓度的降低会导致电池内阻的急剧上升,其脱盐速率也大幅度降低。当盐水浓度为1 g/L时,运行48 h后,内阻由217Ω上升为793Ω。为了实现能量自给的深度脱盐,提出用MDC驱动MCDI深度脱盐的连用技术。当处理1 g/L的低浓度含盐水时,MCDI的处理效果要远高于传统的电容脱盐技术(CDI)的处理效果。与0.8 V的直流稳压电源相比,以MDC作为MCDI供电可使MCDI具有更高的电吸附容量,当两个MDC并联为MCDI供电时,MCDI的吸附容量为直流稳压电源供电的1.6倍。MDC与MCDI系统耦合后不仅实现对MCDI脱盐的连续运行,并且MDC自身在供电的同时,相比于固定外阻200Ω的条件下,脱盐室的电导率下降速度提高了36.2%。经过MDC与MCDI联用处理18个周期后,处理水可以达到饮用标准。经过5500h的运行,生物阴极MDC的功率密度、库伦效率及脱盐速率分别下降71%,44%和27%,主要是由于阴离子交换膜和阳离子交换膜上的生物沉积造成的。膜污染不仅会引起膜通透性的下降,还会升高电池的内阻。对系统内微生物相的分析表明,MDC阳极微生物多样性要低于报道的MFC阳极微生物组成。在MDC中Proteobacteria的含量要高于MFC阳极中大约30%。在MDC系统中,阴极生物膜中的Planctomycetes含量要远高于阳离子交换膜(CEM),表明生物阴极的好氧反应有助于Planctomycetes累积。经过长期运行后,发现脱盐室内会出现微生物污染。脱盐室内微生物污染的主要原因是阳极内的有机物成分通过AEM进入到脱盐室内污染了脱盐水。为解决该问题,设计了带缓冲室的四室MDC,分别增加了质子交换膜(PMDC)和增设阳离子交换膜(CMDC)。与三室MDC相比,PMDC和CMDC在外电阻1000Ω情况下两端电压分别下降33.8%和37.4%。对于初始浓度为35 g/L的盐溶液,在前240 h内,PMDC的脱盐性能优于三室MDC。并且PMDC能够有效地防止乙酸根和磷酸根进入到盐水中,PMDC中乙酸根和总磷的转移量分别为105.7±26.3 mg/L和28.8±9.8 mg/L,只是MDC中的15.8%和35.6%。采用生物阴极MDC和膜电容脱盐法技术,能够将模拟海水(Na Cl浓度35 g/L)的含盐量降到饮用水标准(氯化物250 mg/L)。但由于其中有机物的渗透问题,仍需要对脱盐后的水进行后续处理。虽然有诸多问题,但MDC-MCDI技术使得远离陆地的海岛及远航船只在不消耗电能的情况下获得淡水成为可能。
[Abstract]:Since 1980, global desalination capacity increased substantially, desalination scale to the highest annual growth at a rate of 30%. In the use of desalination increased drinking water at the same time, the energy consumption is huge, in the recent construction of reverse osmosis desalination plant, energy consumption is about 3 to 4 K Wh/m3, the energy shortage and high operating cost, limits its wide application. Especially for away from the land of the island and maritime operations ships and other special circumstances, because there is not enough power to get fresh water from seawater desalination.2009, microbial fuel cell (Microbial desalination, cell, MDC) makes in the consumption of electrical energy to achieve desalination possible. After 5 years of study, although the MDC technology improves the efficiency of desalination, but because MDC is still difficult to follow the use of cathode Using potassium ferricyanide solution or expensive platinum ring (Pt) air cathode catalyst, limiting the MDC expansion, to reduce the possibility of practical application. In the MDC desalination process, with the decrease of desalination chamber salt concentration, resistance of the system resulting in a significant decrease in the efficiency of desalination, this characteristic also makes MDC is not suitable for the low concentration of salt water, to the desalination of seawater to drinking standards. To solve the above problems, the research on sustainable development of cheap catalyst, made a systematic study of MDC and other technical aspects. The coupling depth desalting is proposed to synchronize the desalination, producing electricity for biocathode MDC purposes; and biocathode MDC generated electricity is used to drive the membrane capacitance (Membrane capacitive deionization, desalination technology MCDI) depth desalting. MDC low cost used in seawater desalination provides a new way to obtain fresh water. Developed with The air microorganism as cathode MDC. cathode catalyst with no microbial aeration as compared to cathode catalyst, MDC biofilm growth on the surface of the cathode electrode can decrease the cathode resistance, improve MDC output voltage and output power, thereby improving the MDC desalination rate. After the stable operation of the highest voltage up to 1000 ohm resistance in external conditions 570 m V, the initial concentration of simulated seawater 35 g/L, 480 h after the operation, the lowest salt concentration can be reduced to below 1 g/L, the removal rate can reach more than 90%. But with lower salt concentration, the desalting rate decreased to below 1 g/L, salt solution, reduce the concentration of indoor 16%.MDC desalination of salt the solution is only 35 g/L when the desalination rate will lead to a sharp rise in the internal resistance of the battery, the desalting rate is also greatly reduced. When the salt concentration was 1 g/L, 48 h after operation, the internal resistance increased to 79 from 217. 3. In order to achieve energy self-sufficiency in desalting, put forward to drive the MCDI MDC for desalting technology. When treated with 1 g/L of low concentration of saline water, the treatment efficiency of MCDI is much higher than the traditional capacitive desalination technology (CDI) treatment effect. Compared with the DC power supply of 0.8 V, with MDC as the MCDI power supply can make the MCDI has a higher adsorption capacity, when the two MDC parallel MCDI power supply, the adsorption capacity of MCDI for the DC power supply 1.6 times.MDC and MCDI coupling system not only realize continuous operation of MCDI desalination, and MDC itself in the power supply at the same time, compared to the fixed external resistance 200 Omega conditions, conductivity decreased desalination chamber rate increased 36.2%. after MDC combined with MCDI treatment after 18 cycles of treatment can reach the standard of drinking water. After the operation of 5500h, power density of biocathode MDC, and the desalting rate efficiency of Kulun Don't drop 71%, 44% and 27%, mainly due to biological deposition of anion and cation membrane. The membrane pollution can not only cause the decline of membrane permeability, the internal resistance of battery is also increased. According to the analysis of the system of microorganisms, microbial diversity is lower than that of MDC anode anode microbial composition. MFC reports the content of Proteobacteria in MDC was higher than that of MFC anode is about 30%. in the MDC system, the content of Planctomycetes cathode in the biofilm is much higher than the cation exchange membrane (CEM), showed that the aerobic reaction biocathode contributes to the accumulation of Planctomycetes. After a long run, found that indoor microbial contamination. Desalination will appear the main reason of microorganisms indoor pollution is desalination of organic compounds in the anode through the AEM into the desalted water desalination indoor pollution. In order to solve this problem, designed with a buffer chamber and four MDC, Increase of the proton exchange membrane (PMDC) and a cation exchange membrane (CMDC). Compared with three MDC, PMDC and CMDC in the voltage across the 1000 resistor under salt solution were decreased 33.8% and 37.4%. for the initial concentration of 35 g/L, within the first 240 h, PMDC 3 and MDC. is better than the desalination performance PMDC can effectively prevent the acetic acid and phosphate into salt water, transfer amount of acetate and total phosphorus in PMDC is 105.7 + 26.3 + 9.8 mg/L and 28.8 mg/L respectively, only 15.8% in MDC and 35.6%. using the technology of bio cathode MDC and membrane capacitance desalination, can be simulated seawater (Na concentration of 35 Cl g/L) the salt content is reduced to the standard of drinking water (250 mg/L chloride). But because the permeability of organic matter, still need follow-up treatment of desalinated water. Although there are many problems, but the MDC-MCDI technology makes the island far away from land and ships in It is possible to get fresh water without consumption of electricity.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P747

【参考文献】