利用啤酒废水发电的上流式生物燃料电池研究

以颗粒活性炭为阳极、气体扩散电极为阴极,以啤酒废水为基质构建了上流式直接空气阴极生物燃料电池(UACMFC),在连续运行条件下考察了其产电性能及进水COD浓度、外接电阻对电池性能的影响。结果表明,啤酒废水的COD浓度越大,UACMFC的输出电压和输出功率就越高,当COD为1 953 mg/L时,UACMFC的最大功率密度为13.54 W/m3;随着外接电阻的增大,对COD的去除量和库仑效率不断减小。试验结果表明,以啤酒废水作为生物燃料电池的燃料进行同步发电和降解有机物具有可行性。     

阳极厚度对填料型微生物燃料电池产电性能的影响

在阴极厚度(100mm)一致时,研究了不同阳极厚度(100、30和10mm)对填料型微生物燃料电池内阻、功率密度和库仑效率的影响.以乙酸钠为基质,采用厌氧污泥接种,三个反应器的启动期基本相同(10～11d).运行稳定后,三个反应器的内阻分别为(19.7±5.1)、(19.9± 5.4)、(22.2±6.0)Ω,阳极内阻分别为(1.1±0.2)、(1.6±0.4)、(3.4±0.2)Ω;最大面积功率密度分别为(689±128)、(672±74)、(637±87)mW/m2;最大体积功率密度分别为(3.4±0.6)、(5.2±0.6)、(5.8±0.8)W/m3;库仑效率分别为(15.1±1.8)%、(18.8±2.1)%和(19.6±0.8)%.可见,随着阳极厚度的增大,反应器的内阻减小,最大面积功率密度增大,但体积功率密度和库仑效率减小.     

微生物燃料电池降解啤酒废水及同步产电特性

通过构建无媒介双室型微生物燃料电池(MFC),考察其降解啤酒废水的效果及同步产电特性。研究了外接电阻、温度和阴极曝气等条件对MFC产电的影响,监测了电池外电压和电极电势的变化过程,分析了微生物燃料电池的运行机理。通过稳态放电法得到以碳纤维布作为阳极材料的双室型微生物燃料电池的内阻为1 000Ω,最大产电功率密度为375 mW/m2。以啤酒废水为底物的MFC对COD的去除率为84%左右,外电压为0.21 V,库仑效率约为15%;而在以葡萄糖为底物的条件下,MFC的外电压为0.3 V,对COD的去除率为89%,产电性能及除污效率均有所提高。     

以葡萄糖为底物的微生物燃料电池产电特性研究

以城市污水处理厂的好氧和厌氧污泥作为接种液,通过构建双室微生物燃料电池,考察了以葡萄糖为底物时连续流微生物燃料电池降解有机物及产电的特性.结果表明:以泡沫镍板、石墨板作为阳极时的产电效果较好;在一定温度范围内,提高温度可增大电池的输出电压和开路电压;对阴极室供氧可提高微生物燃料电池的开路电压和输出电压;随着外接电阻值的增大,微生物燃料电池的输出电流变小,符合原电池电极的一般规律.     

盐室和基质浓度对微生物脱盐电池性能的影响

微生物脱盐电池(MDC)是一种集污水净化、产电和脱盐为一体的新型水处理工艺。构建并运行了10 L级堆叠式树脂填充型微生物脱盐中试装置,考察了盐室初始浓度及阳极进水基质浓度对MDC运行效果的影响。初始盐室浓度升高时,平均电流较高,平均脱盐速率提高,但脱盐率降低;阳极基质降解速率基本符合米氏方程,当基质COD75 mg/L时,近似于零级反应,COD降解速率为71.5 mg/(L·h);在阳极水力停留时间为6 h且连续流运行模式下,当阳极进水COD在150~600 mg/L变化时,阳极出水COD浓度随进水COD浓度增加而增加,但阴极出水COD浓度均低于城市污水排放一级A标准限值,平均电流随进水COD浓度上升,脱盐率为64.1%~82.1%。这为进一步放大MDC反应器并研究脱盐速率提供了参考。     

初始干密度对非饱和土变形及强度影响的试验研究

通过压力板仪测定并对比分析了不同初始干密度下粉质黏土的土水特征曲线;使用GDS非饱和土三轴仪,进行了不同初始干密度、不同基质吸力下非饱和粉质黏土的强度试验。结果表明:van Genuchten模型可以较好拟合不同初始干密度粉质黏土土水特征曲线;试样进气值与初始干密度呈正相关,持水能力和水稳定性随初始干密度的增大逐渐增大;相同初始干密度的非饱和粉质黏土强度随基质吸力的增大而增大,随着基质吸力的增大,基质吸力对试样抗剪强度的贡献值逐渐变小。不同初始干密度的试样体积变化均随着基质吸力的增大而减小,且初始干密度越大,不同基质吸力试样体变越接近一致。重塑非饱和粉质黏土的应力-应变关系可以用双曲线模型来描述,试样切线模量随基质吸力的增大而增大。     

不同环境下有机防护型阻锈剂阻锈效果研究

钢筋锈蚀导致的结构破坏日趋严重。使用阻锈剂是防止锈蚀的一种主要手段,试验采用有机防护型阻锈剂,通过分析碳钢电极在不同阻锈剂浓度、pH值、Cl-浓度以及不同温度时混凝土模拟孔溶液中的电化学行为,利用交流阻抗谱法分析有机防护型阻锈剂的阻锈效果。研究得出,有机防护型阻锈剂能有效的防止钢筋锈蚀,且随着阻锈剂浓度的增加,阻锈效率逐渐升高;随着模拟孔溶液pH值的增大,阻锈效率呈先增大后减小的趋势,在pH=11.3时达到最大;考虑氯离子浓度和温度不同的影响时,得到在氯离子浓度为3.5%、温度为25℃时阻锈效率最大。通过试验研究全面分析了在不同环境下有机防护型阻锈剂的阻锈效果,为有机防护型阻锈剂的广泛应用提供了科学依据。     

双圆筒曝气阴极微生物燃料电池处理猪场废水研究

通过构建双圆筒曝气阴极微生物燃料电池(MFC)系统并处理实际猪场废水,可使能源利用与环境保护紧密结合。研究了系统的启动过程,启动完成后微生物在电极表面的形态,以及稳定运行过程中输出电压的变化、对COD的去除效果、最大功率密度、表观内阻、库仑效率。结果表明:采用实际猪场废水成功启动MFC后,阳极表面附着大量的球菌。稳定运行一个周期,能够获得700mV的稳定输出电压,对COD的去除率为74.8%,库仑效率为12.8%,最大输出功率密度为1.02W/m~2,表观内阻为23.25Ω,开路电压为821.5mV。而在优化条件下,能获得600mV的稳定输出电压,对COD的去除率为73.8%,库仑效率为20.9%。     

微波协同低碱预处理对污泥MFC性能的影响

分别以原泥、微波预处理污泥和微波协同低碱预处理污泥为微生物燃料电池(MFC)的阳极底物,通过比较其产电性能和污泥泥质变化,考察微波协同低碱预处理技术对改善MFC污泥资源化效果的影响。结果表明,污泥经微波协同低碱预处理后,进一步提高了MFC的产电能力和污泥降解效果。微波协同低碱预处理组的稳定输出电压升至(610±10)m V(外阻R=500Ω),稳定时间延长至17 d;最大产电功率密度提高到14.90 W/m3;反应器运行23 d,对TCOD的去除率增至43.5%,库仑效率提高到6.59%。随着反应器的运行,以预处理污泥为底物的MFC,污泥SCOD浓度先下降后上升,而以原泥为底物时污泥SCOD浓度始终处于上升趋势;氨氮浓度随反应器运行先上升然后逐渐降低;污泥p H值一直下降,且微波协同低碱预处理组下降最多。     

山岭隧道衬砌换热器地源热泵能效的影响因素研究

为了分析山区环境下的隧道衬砌换热器地源热泵能效,建立了隧道衬砌换热器的瞬态传热三维数值计算模型。分析了制冷工况下隧道衬砌换热器地源热泵的运行能效。分析结果表明：地源热泵能效比随着风速的增大先减小后增大;随着围岩导热性的增强而增大,但增大速率逐渐降低;随着围岩初始地温的升高呈线性减小。上述因素敏感性分析结果表明,风速对隧道衬砌换热器地源热泵能效比的影响程度最小,初始地温最大。随着管长的增加,初始地温对地源热泵能效比影响权重逐渐增大,风速和围岩导热系数的影响权重逐渐减小。     

The effect of real-time external resistance optimization on microbial fuel cell performance

This work evaluates the impact of the external resistance (electrical load) on the long-term performance of a microbial fuel cell (MFC) and demonstrates the real-time optimization of the external resistance. For this purpose, acetate-fed MFCs were operated at external resistances, which were above, below, or equal to the internal resistance of a corresponding MFC. A perturbation/observation algorithm was used for the real-time optimal selection of the external resistance. MFC operation at the optimal external resistance resulted in increased power output, improved Coulombic efficiency, and low methane production. Furthermore, the efficiency of the perturbation/observation algorithm for maximizing long-term MFC performance was confirmed by operating an MFC fed with synthetic wastewater for over 40 days. In this test an average Coulombic efficiency of 29% was achieved.     

碱处理污泥为底物的微生物燃料电池产电特性

利用剩余污泥作为接种体,在不添加任何营养元素的情况下,成功启动了两室型微生物燃料电池(MFC)。对剩余污泥进行碱解预处理,考察将其作为MFC底物的可行性,同时分析了剩余污泥经不同时间的碱处理,MFC产电性能的变化及其对污泥的降解效果。结果表明:利用碱预处理污泥作为底物时,MFC的稳定输出电压、最大产电功率密度和对TCOD的去除率均提高,同时周期运行时间延长。并且,随着碱处理时间的延长,MFC的稳定输出电压、产电功率密度和对TCOD的去除率均增大。当碱处理时间为24 h时,稳定输出电压达到630 mV(外阻R=500Ω),最大产电功率密度为11.73 W/m3,对TCOD的去除率为25.3%。这与碱处理使得固体有机物被水解有关。     

Effect of nitrate on the performance of single chamber air cathode microbial fuel cells

The effect of nitrate on the performance of a single chamber air cathode MFC system and the denitrification activity in the system were investigated. The maximum voltage output was not affected by 8.0mM nitrate in the medium solution at higher external resistance (270-1000Omega), but affected at lower resistance (150Omega) possibly due to the low organic carbon availability. The Coulombic efficiency was greatly affected by the nitrate concentration possibly due to the competition between the electricity generation and denitrification processes. Over 84-90% of nitrate (0.8-8.0mM) was removed from the single chamber MFCs in less than 8h in the first batch. After 4-month operation, over 85% of nitrate (8.0mM) was removed in 1h after the MFC was continuously fed with a medium solution containing nitrate. Only a small amount of nitrite (<0.01mM) was detected during the denitrification process. The similar denitrification activity observed at different external resistances (1000 and 270Omega) and open circuit mode indicates that the denitrification was not significantly affected by the electricity generation process. No electricity was generated when the MFC fed with 8.0mM nitrate was moved to a glove box (no oxygen), indicating that the bacteria on the cathode did not involve in accepting electrons from the circuit to reduce the nitrate. Denaturing Gradient Gel Electrophoresis (DGGE) profiles demonstrate a similar bacterial community composition on the electrodes and in the solution but with different dominant species.     

负离子空气净化器去除氨气的试验研究

针对负离子空气净化器去除氨气的有效性开展了试验研究.利用风道式空气净化性能实验台研究了负离子去除氨气的效率与迎面风速、外施电压、初始氨气浓度的关系.在环境试验舱里测试了负离子净化器样机去除氨气性能的有效性.结果 表明:负离子样机能较有效地去除氨气;在其他条件不变时,该负离子装置对氨气的去除效率随风速的增大而逐渐降低;随...     

A comparative study on treatment of wastewaters with various biodegradability and various pH values using single‐chamber microbial fuel cells

This work assessed the performance of a single‐chamber microbial fuel cell (MFC) with various substrates. Primary settled domestic wastewaters were used to simulate wastewaters of high biodegradability; while phenol‐based wastewaters and benzene‐based wastewaters were used to simulate wastewaters of low biodegradability. Experiments were performed at initial pH values of 6, 7 and 8. The maximum voltage production, power density and removal of substrate were obtained using primary settled domestic wastewater, whereas the lowest values were obtained using phenol‐based wastewater. The maximum chemical oxygen demand removal efficiency, phenol removal efficiency and benzene removal efficiency were 80.8, 63.3 and 77.8%, respectively. The performance of the MFC was enhanced by increasing the influent pH. The lowest coulombic efficiencies were obtained from phenol‐based wastewater and benzene‐based wastewater, which indicated that electrogenic bacteria were not the primary microorganisms responsible for the biodegradation of low biodegradable wastewater.     

Electricity generation from cysteine in a microbial fuel cell

In a microbial fuel cell (MFC), power can be generated from the oxidation of organic matter by bacteria at the anode, with reduction of oxygen at the cathode. Proton exchange membranes used in MFCs are permeable to oxygen, resulting in the diffusion of oxygen into the anode chamber. This could either lower power generation by obligate anaerobes or result in the loss in electron donor from aerobic respiration by facultative or other aerobic bacteria. In order to maintain anaerobic conditions in conventional anaerobic laboratory cultures, chemical oxygen scavengers such as cysteine are commonly used. It is shown here that cysteine can serve as a substrate for electricity generation by bacteria in a MFC. A two-chamber MFC containing a proton exchange membrane was inoculated with an anaerobic marine sediment. Over a period of a few weeks, electricity generation gradually increased to a maximum power density of 19 mW/m(2) (700 or 1000 Omega resistor; 385 mg/L of cysteine). Power output increased to 39 mW/m(2) when cysteine concentrations were increased up to 770 mg/L (493 Omega resistor). The use of a more active cathode with Pt- or Pt-Ru, increased the maximum power from 19 to 33 mW/m(2) demonstrating that cathode efficiency limited power generation. Power was always immediately generated upon addition of fresh medium, but initial power levels consistently increased by ca. 30% during the first 24 h. Electron recovery as electricity was 14% based on complete cysteine oxidation, with an additional 14% (28% total) potentially lost to oxygen diffusion through the proton exchange membrane. 16S rRNA-based analysis of the biofilm on the anode of the MFC indicated that the predominant organisms were Shewanella spp. closely related to Shewanella affinis (37% of 16S rRNA gene sequences recovered in clone libraries).     

Modelling study of an upflow microbial fuel cell catalysed with anaerobic aged sludge

An electrochemical model for an upflow dual-chambered microbial fuel cell (MFC) process is proposed in this study. The model was set up on the basis of the experimental results and the analysis of biochemical and electrochemical processes in the MFC biocatalysed with anaerobic aged sludge and alternatively fuelled with a synthetic acetate-based and actual domestic wastewaters. Simulation of the process shows that the model describes the process reasonably well with correlation coefficients higher than 0.97. The analysis of model simulation illustrates how the current output depends mainly on the substrate concentration as well as other main variables. The relationship between the current output and over-voltage is revealed by the modelling study. For acetate-based wastewaters with initial chemical oxygen demand (COD) concentrations of 350, 700, 1050, and 1400 mg/L, maximum observed power densities were 290, 405, 448, and 525 mW/m² associated with maximum COD removals of 84%, 88%, 83%, and 82%, respectively.     

两瓶型微生物燃料电池处理垃圾渗滤液的研究

采用两瓶型微生物燃料电池(MFC)处理垃圾渗滤液,考察了其产电情况和对污染物的降解效果.结果表明:渗滤液中的有机物在阳极室得到了较好的去除,当进水COD为1 105mg/L时,对COD的去除率约为78.3%.随着渗滤液比例的增大,电流密度和功率密度逐步下降,这是由于阳极室溶液的电导率下降造成的.随着渗滤液浓度的增加,输出电压、电流密度和功率密度增大,同时MFC的产电周期明显延长,从COD为502 mg/L时的4d增加到COD为1105mg/L时的近7d.当以渗滤液为底物时,相比以乙酸钠为底物的情况,MFC的最大功率密度有所降低,从2.0 W/m3下降为0.78 W/m3,内阻也有所增大,从300Ω增加到约500Ω.