Recent advance in microbial fuel cell reactor configuration and coupling technologies for removal of antibiotic pollutants

Microbial fuel cell (MFC) technology, as a biological treatment model that can convert antibiotic pollutants into electrical energy, has attracted extensive attention in recent years. Reactor configuration and coupling process play an important role in the treatment of antibiotic wastewater by the MFC, which will affect microbial activity, pollutant removal, and electricity generation. In this review, recent advances of reactor configuration (single chamber, double chamber, and cylinder) and coupling technology (wetland-MFC, sediment-MFC and membrane-MFC, and so on) of the MFC on treating of antibiotics are summarized, and their characteristics in the aspects of pollutant removal and power output are analyzed. Finally, through comparing removal quantity (mg antibiotics per day), the double chamber MFC as the individual treatment unit and the membrane-MFC exhibit better removal quantity.     

Recent advancements in real-world microbial fuel cell applications

This short review focuses on the recent developments of the Microbial Fuel Cell (MFC) technology, its scale-up and implementation in real world applications. Microbial Fuel Cells produce (bio)energy from waste streams, which can reduce environmental pollution, but also decrease the cost of the treatment. Although the technology is still considered “new”, it has a long history since its discovery, but it is only now that recent developments have allowed its implementation in real world settings, as a precursor to commercialisation.     

Optimization for the improvement of power in equal volume of single chamber microbial fuel cell using dairy wastewater

Microbial fuel cells (MFCs) are a type of sustainable technology that may treat wastewater and generate power at the same time. Therefore, researchers are being challenged to design a technically feasible bio electrochemical system that generates environmentally friendly and renewable electricity from waste water. The current research examined at how MFC may be used to generate electricity while treating real dairy wastewater (RDW) with Pseudomonas aeruginosa-MTCC-7814. The experiments were carried out in fed-batch mode for 15 days in two 300 ml single chamber microbial fuel cells (SCMFCs) that were connected in series. During a fed batch investigation, three process parameters such as inoculum percentage, temperature, and pH were optimized. Inoculum percentage, temperature, and pH were found to be optimal at 5%, 37 °C, and 7.4, respectively and the highest open-circuit voltage was found to be 1025 mV. The COD removal efficiency and columbic efficiency (CE) were found to be 95.84% and 37.13% respectively. The optimized fed batch process yielded the maximum current density and power density of 313 mA/m² and 105 mW/m², respectively. Thus, this work successfully demonstrates that connecting single chamber microbial fuel cells (SCMFCs) in series is a viable technique for generating sustainable power utilizing Pseudomonas aeruginosa-MTCC-7814 from dairy wastewater.     

双极室联合处理啤酒废水的微生物燃料电池

构建了双极室连续流联合处理废水的微生物燃料电池(MFC), 该MFC阳极室的出水直接用于阴极室的进水, 利用阴极室的好氧微生物进一步降解有机物. 以啤酒废水作底物, 研究了该MFC的产电性能和废水处理效果. 结果表明, 采用双极室连续流MFC可以大大提高废水的处理效果, 对啤酒废水化学需氧量(COD)的总去除率可达92.2%~95.1%, 其中阳极室中COD去除率为47.6%~56.5%. MFC的开路电压为0.451 V, 最大输出功率为2.89 W/m³. 实验中抑制MFC性能的主要因素是阴极的极化损失, 通过降低进入阴极室溶液的COD浓度、采用优质的阴极材料和加大阴极室内的曝气量等方法进一步优化电池的性能.     

氧化还原导电水凝胶制备及其在微生物燃料电池的应用

微生物细胞与微生物燃料电池阳极之间的电子传递效率是影响产电性能的关键因素.借助阳极修饰可以促进电子转移速率,提高电池的性能.本文合成了一种以聚4-乙烯基吡啶为骨架,中性红单体为氧化还原活性中心、具有良好导电性和生物兼容性的氧化还原水凝胶材料.其中通过共价键合固定氧化还原中介体,避免了对外界环境的二次污染.以该材料修饰碳纸作为阳极组装电池,实验表明经过修饰的生物阳极驯化周期缩短,阳极电势更接近NADH/NAD的平衡电位.该电池的功率密度较未修饰的电极的电池有明显的提高.     

Optimization of double chamber microbial fuel cell for domestic wastewater treatment and electricity production

Microbial fuel cells (MFCs) represent a new approach for treating waste water along with electricity production. The present study addressed electricity production from domestic wastewater using a mediator-less double chamber MFC. The electricity production was monitored under different operational conditions for both summer and winter samples. Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 mA with the maximal power intensity of 209 and 117 mW/m² in power duration of 24 h for the summer and winter samples, respectively. Scanning electron microscopy showed that the bacterial biofilm formation on the anode was denser for the summer sample than that when the winter sample was used, so was the total bacterial count. Therefore, samples taken during summer were considered better in electricity production and waste water treatment than those taken during winter basically because of the high microbial load during the hot season. In parallel, there was a decrease in both biological oxygen demand (BOD₅) and chemical oxygen demand (COD) values which reached 71.8% and 72.85%, respectively at the end of the operation process for the summer sample, while there was no evident decrease for the winter sample. Optimizing the operating conditions not only increased the potential of using domestic waste water in microbial fuel cells to produce electricity, but also improved the quality of the domestic waste water.     

Insights into recent advances of chitosan-based adsorbents for sustainable removal of heavy metals and anions

With globally increased human population and industrialization, the natural sources of water are reduced and then contaminated. Therefore, development of advanced technologies for the efficient water treatment is becoming of the scope of each of the nation. One of the cost-effective and well-known technologies for wastewater treatment is adsorption of contaminants by natural biopolymer like chitosan (CS) due to its unique features such as availability, biodegradability, biocompatibility, eco-friendly and low-cost production. However, Cs suffers considerable limitations such as low adsorption capacity, low surface area and limited reusability. Thence, this review intended to provide an overview for recent advances of chitosan-based adsorbents that established better adsorption activities towards various hazard heavy metals, including: As(III), As(V), Cu(II), Cr(VI), Pb(II) and Cd(II) ions. In addition, the capabilities of chitosan-based adsorbents for the adsorptive removal of anions including phosphates and nitrates were discussed. Besides, the suggested adsorption mechanisms of these contaminants onto chitosan-based adsorbents and the research conclusions for the optimum conditions of the adsorption processes were explained in light of the currently reported studies. Furthermore, to emphasize the foremost research gaps and future potential trends that could inspire further researchers to find out the best solutions for water treatment problems.     

Electricity generation by an enriched phototrophic consortium in a microbial fuel cell

Microbial fuel cell (MFC) technology is a novel electricity generation process catalyzed by microorganisms. Much progress is made in the design and construction of MFCs, however the diversity of the electrochemically active microorganisms and the electricity generation mechanisms remain a black box. As sun is a predominantly unused energy resource, here we present a highly enriched phototrophic consortium that can produce electricity in an “H” typed MFC at a high power density (2650 mW m⁻², normalized to membrane area) in light, which was eightfold of that produced by non-enriched consortium in the same reactor. Light–dark shift experiments showed that light contributed to the electricity generation. A microbial excreted mediator assisted the electron transfer to the electrode. During the experiment, the accumulation of the mediator over time enhanced the electron transfer rate. The excitation–emission matrix fluorescence spectroscopy results indicated indole group containing compound representing the dominant mediator component.     

Development of a Novel Membrane‐less Microbial Fuel Cell (ML‐MFC) with a Sandwiched Nitrifying Chamber for Efficient Wastewater Treatment

A novel membrane‐less microbial fuel cell (ML‐MFC) which used the baffles instead of the ion exchange membrane (IEM) was developed for ammonium‐containing wastewater treatment and electricity generation. By means of installing an ideal nitrifying unit between the anodic and cathodic chamber, the novel ML‐MFC accomplished organics degradation and nitrogen removal without additional loop. The removal efficiencies of COD, NH₄⁺−N and TN achieved 97.07±0.47 %, 91.76±3.32 % and 87.66±1.59 %, respectively. Meanwhile, the effluent pH was near neutral and turbidity was quite low. In addition, the maximum power density of 1.007±0.032 W/m³ was obtained. Combined with the analysis of microbial community, electroactive bacteria (EAB) Desulfovibrio, Comamonas and Thiobacillus were enriched in biofilm. Considering the superior effluent quality and the promising energy potential, the novel ML‐MFC has good application prospects in efficient and sustainable wastewater treatment.     

Applicability of Alginate Film Entrapped Yeast for Microbial Fuel Cell

New strategies are proposed for modification of the anode of a Microbial Fuel Cell (MFC). Immobilization of yeast cells as electrogenic microorganism in MFC was reported using alginate. Yeast cells entrapment within alginate matrices was done through films deposited at the surface of a carbon felt electrode and the resulting anodes were characterized by chronoamperometry. Yeast entrapped within alginate films on carbon felt oxidized glucose and generates a current by direct and mediated electrons transfer from yeast cells to the carbon electrode. The result substantiated that immobilization of yeast for MFC could be a promising method to product green electricity.

     

共基质改善MFC处理链霉素废水及产电性能的研究

以K_3[Fe(CN)_6]和NaCl混合溶液为阴极液,以驯化的人工湖泊底泥为微生物菌种,以链霉素废水为阳极液,构建微生物燃料电池实验系统,研究添加共基质前后微生物燃料电池的废水处理效果与同步发电性能。结果表明,以链霉素废水为阳极液的微生物燃料电池的产电能力及废水处理效果均较差,并且随着链霉素浓度的增大而进一步恶化;但将葡萄糖作为共基质添加至阳极链霉素废水后,微生物燃料电池的产电能力和废水处理效果均显著提高。链霉素浓度为50 mg/L时,未添加共基质的微生物燃料电池处理链霉素废水的COD去除率为52%,产电电流密度为25 m A/m~2,输出电压为4.72 m V;添加共基质后,COD去除率为92%,稳态产电电流密度为300 m A/m~2,稳态输出电压为54 m V。     

微生物燃料电池生物阴极

微生物燃料电池(microbial fuel cells, MFCs)利用微生物处理废水的同时产电,是一种清洁可再生能源技术。近年来新兴起的生物阴极是指阴极室中的功能微生物附着在电极表面形成生物膜,电子由电极传递给微生物并发生相应的生物电化学反应;是微生物燃料电池研究的一个重要方向。本文根据厌氧、好氧操作体系的不同将生物阴极进行分类;归纳总结了微生物组成、电极和分隔材料的研究进展,探讨了生物阴极在去除污染物和生成高附加值产品中的实际应用,并提出了其将来发展的可能方向。     

Engineering nanostructures of CuO-based photocatalysts for water treatment: Current progress and future challenges

Nowadays, increasing extortions regarding environmental problems and energy scarcity have stuck the development and endurance of human society. The issue of inorganic and organic pollutants that exist in water from agricultural, domestic, and industrial activities has directed the development of advanced technologies to address the challenges of water scarcity efficiently. To solve this major issue, various scientists and researchers are looking for novel and effective technologies that can efficiently remove pollutants from wastewater. Nanoscale metal oxide materials have been proposed due to their distinctive size, physical and chemical properties along with promising applications. Cupric Oxide (CuO) is one of the most commonly used benchmark photocatalysts in photodegradation owing to the fact that they are cost-effective, non-toxic, and more efficient in absorption across a significant fraction of solar spectrum. In this review, we have summarized synthetic strategies of CuO fabrication, modification methods with applications for water treatment purposes. Moreover, an elaborative discussion on feasible strategies includes; binary and ternary heterojunction formation, Z-scheme based photocatalytic system, incorporation of rare earth/transition metal ions as dopants, and carbonaceous materials serving as a support system. The mechanistic insight inferring photo-induced charge separation and transfer, the functional reactive radical species involved in a photocatalytic reaction, have been successfully featured and examined. Finally, a conclusive remark regarding current studies and unresolved challenges related to CuO are put forth for future perspectives.     

微生物电解电池制氢*

在微生物燃料电池（MFC）的基础上发展而来的微生物电解电池（MEC）为生物制氢提供了一种全新的方法。本文综述了自2005年MEC发明以来取得的研究进展。简要介绍了MEC制氢的基本原理和系统的评价参数;比较了不同MEC系统结构和电极材料对体系产氢效能的影响;讨论了MEC制氢实际应用中存在问题和限制因素;提出了MEC制氢今后的研究思路和发展趋势;展望了MEC在利用生物质制氢和有机废水资源化利用中的应用前景。     

石墨烯基杂化材料在微生物燃料电池电极中的应用

微生物燃料电池（MFC）是利用生物催化剂将污水有机物中的化学能直接转化为电能的技术,因其功率密度和能量转化效率低,电极制作成本高,限制了其大规模实际应用。因此如何提高电极的催化性能并降低电极制作成本成为MFC的研究重点方向。由于石墨烯基杂化材料具有良好的导电性和催化特性,因此石墨烯基杂化材料成为在MFC电极应用中的热点之一。本文综述了近年来MFC石墨烯基杂化电极材料的最新研究进展,重点讨论了改性石墨烯电极、金属及非金属/石墨烯杂化电极、金属氧化物/石墨烯杂化电极、聚合物/石墨烯杂化电极和石墨烯凝胶电极的设计思路和制备方法及其催化性能,着重分析了石墨烯基阳极和阴极杂化材料对MFC产电性能的影响。最后对石墨烯基杂化材料在MFC应用中存在的问题及研究前景进行了总结和展望。     

Comparative Study of Electrochemical Performance and Microbial Flora in Microbial Fuel Cells by Using Three Kinds of Substrates

This work aimed to investigate the distinct electrochemical performance and microbial flora of microbial fuel cells(MFCs)in relation to different single hazardous fed fuels.Three replicate MFCs were inoculated with the same microbial consortium from a coking wastewater treatment plants wherein ammonium chloride(ammoniiim chlo-ride-fed MFC,N-MFC),phenol(phenol-fed MFC,P-MFC)and potassium sulphide(potassium sulphide-fed MFC,S-MFC)were the sole substrates and main components of real coking wastewater.With initial concentrations of am-monium chloride,phenol and potassium sulphide of 0.75,0.60 and 0.55 g/L,the removal efficiencies reached 95.6%,90.6%and 99.9%,respectively,whereas the peak output power densities totalled 697,324 and 1215 mW/m^2.Micro-bial community analysis showed that the respective addition of substrate substantially altered the microbial community structure of anode biofllm,resulting in changes in relative abundance and emergence of new strains and further affecting the electrochemical properties of MFCs.The chemical oxygen demand(COD)removal efficiency of real coking wastewater,in which,the inoculum was the combined biomass from the three MFCs,reached 82.3%.     

用于生物电化学系统的石墨烯电极新进展

可持续社会的发展需要成本低, 并从废物或废水中提取能源或将能源转化为产品的环境友好技术. 近年兴起的生物电化学系统(BESs)利用微生物催化不同电化学反应, 是将废物或废水中能量转化为电能等多种产品的发展前景广阔的新技术. 当有关反应的吉布斯自由能小于零, 系统输出电能, 此时的BESs即为微生物燃料电池(MFCs); 相反, 若反应的吉布斯自由能为正值, 此时的BESs被称为微生物电解电池(MECs). 随着研究工作的不断深入和拓展, BESs的电极性能已成为制约其应用的瓶颈. 石墨烯以其独特的结构和优异的材料性能在BESs领域, 特别是MFCs中得以应用. 本文参考了最新的文献资料, 综述了石墨烯应用于BESs的发展现状, 包括应用于MFCs的石墨烯电极、掺杂石墨烯电极、担载石墨烯电极, 对其在MECs中可能的应用, 以及未来发展趋势予以展望.     

阳极改性对微生物燃料电池处理秸秆水解物性能影响

以玉米秸秆稀酸水解液为阳极底物,用污水处理厂活性污泥为产电微生物菌源构建双室微生物燃料电池(MFC),采用三种不同方法改性阳极碳毡,并对其MFC产电性能进行研究。结果表明,以未改性碳毡(CC)、HNO_3酸解CC(HNO_3/CC)、壳聚糖改性CC(chitosan/CC)、PDADMAC/α-Fe_2O_3层层自组装改性碳毡(PDADMAC/α-Fe_2O_3/CC)的MFC的最大产电量分别为248、315、452和522 mV,最大功率密度分别为54.6、92.7、203.8和248.1 mW/m~2,COD的去除率分别为82.21%、81.46%、82.53%和86.44%。循环伏安曲线显示,PDADMAC/α-Fe_2O_3层层自组装改性的阳极碳毡具有较高的氧化还原电位。电化学阻抗谱图表明,PDADMAC/α-Fe_2O_3层层自组装改性碳毡的极化内阻最小,为7Ω。几种改性材料为阳极的MFC性能依次为PDADMAC/α-Fe_2O_3/CC壳聚糖/CCHNO_3/CC空白CC。     

Discover the possibilities: microbial bioelectrochemical systems and the revival of a 100-year�Cold discovery

Microbial fuel cells (MFC) can be considered as archetype microbial bioelectrochemical systems that exploit the bioelectrocatalytic activity of living microorganisms for the generation of electric current. ??Microbial fuel cells represent a novel technology that is still in its infancy?? is a typical statement in the current articles to describe the state of research on microbial fuel cells. It is a quite absurd statement for a technology that to the date has a history of 100?years. At the same time, it is quite correct since the actual, systematic MFC development has started only about a decade ago. The history of the MFC development reads like a science fiction novel??we read about space research and autonomous robots (??gastrobots??). But yet, the current tremendous interest in this technology is rather down to earth??it is about energy recovery and wastewater treatment. To understand the presence and to predict and actively shape the future, it is a good opportunity to look into and learn from the past. This article shall go on a short journey through the past 100?years of microbial fuel cells. This is not to be understood as a comprehensive and complete survey of the MFC literature and development. It is rather a personal view on critical aspects in the past development and the possible future of this technology.     

Electrochemical disinfection – State of the art and tendencies

Electrochemical disinfection has gained increasing interest in many sectors of social and industrial life. The reason is the growing need to disinfect the air, water, and special surfaces of different nature such as drinking water, wastewater, pool water, and other water qualities or surfaces. New research studies are reported and discussed. A stronger orientation on engineering aspects is intended. Following tendencies can be identified - research on complex liquid systems, implementation of risks consideration seen from by-product formation, and better cooperation between researchers and industry oriented to improve cell design and disinfection technology. Partially, reaction kinetics is studied and discussed at higher levels of likelihood. Furthermore, it can be found that more and more research papers deal with hybrid technologies to create novelty, to use synergistic effects and to meet the demands of real system treatment under practical conditions. A major focus can be identified for wastewater treatment/disinfection emphasizing electrocoagulation and electro-photocatalysis.