Overview on the developments of microbial fuel cells

Electricity generation from biomass has captured a lot of attention these days. Many countries have inclined to start large-scale research projects so that the microbial fuel cells could be installed to fulfill the power requirements of domestic as well as industrial sectors. The chemical energy stored in the algal biomass can be harnessed for sustainable production of fuels and other value-added products. Bioelectricity production using algae seems to be a wise approach to extract energy from sunlight in an economic and sustainable manner. It is achieved through integration of photosynthesis with microbial fuel cell (MFC). Algae have been used commonly in MFCs to reduce oxygen at cathode or as a substrate for bacteria. However, sufficient electric current can also be generated at anode, where cytochromes help indirect shuttling of electrons generated in photosystem II of the algal cells and can be called as photosynthetic algal microbial fuel cell (PAMFC). Despite being environmental friendly, low efficiency makes these neoteric systems unviable. Hence, a good understanding is needed for the bioelectrochemical mechanisms working behind the electron transfer from algae to electrode. Oxygen is also a limiting factor among different variables viz. pH, substrate loading rate etc., affecting the fuel cell performance. The present review addresses the mechanism of electron transfer in algae and algae to electrode and the factors affecting the performance of PAMFC.

Algal growth in photosynthetic algal microbial fuel cell and its subsequent utilization for biofuels

Recent insights into microalgae-assisted microbial fuel cells for generating sustainable bioelectricity

Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are promising bioelectrochemical systems (BESs) for simultaneous wastewater treatment and energy/resource recovery. Unlike conventional fuel cells that are based on stable chemical reactions, these BESs are sensitive to environmental and operating conditions, such as temperature, pH, external resistance, etc. Substrate type, electrode material, and reactor configuration are also important factors affecting power generation in MFCs and hydrogen production in MECs. In order to discuss the influence of these above factors on the performance of MFCs and MECs, this study analyzes published data via data synthesis and meta-analysis. The results revealed that domestic wastewater would be more suitable for treatment using MFCs or MECs, due to their lower toxicity for anode biofilms compared to swine wastewater and landfill leachate. The optimal temperature was 25–35 °C, optimal pH was 6–7, and optimal external resistance was 100–1000 Ω. Although systems using carbon cloth as the electrodes demonstrated better performance (due to carbon cloth’s large surface area for microbial growth), the high prices of this material and other existing carbonaceous materials make it inappropriate for practical applications. To scale up and commercialize MFCs and MECs in the future, enhanced system performance and stability are needed, and could be possibly achieved with improved system designs.

https://www.mdpi.com/2313-0105/4/3/34/pdf

Factors Affecting the Effectiveness of Bioelectrochemical System Applications: Data Synthesis and Meta-Analysis

The interspecies electron transfer (IET) between microbes and archaea is the key to how the anaerobic digestion process performs. However, renewable energy technology that utilizes the application of a bioelectrochemical system together with anaerobic additives such as magnetite-nanoparticles can promote both direct interspecies electron transfer (DIET) as well as indirect interspecies electron transfer (IIET). This has several advantages, including higher removal of toxic pollutants present in municipal wastewater, higher biomass to renewable energy conversion, and greater electrochemical efficiencies. This review explores the synergistic influence of bioelectrochemical systems and anaerobic additives on the anaerobic digestion of complex substrates such as sewage sludge. The review discussions present the mechanisms and limitations of the conventional anaerobic digestion process. In addition, the applicability of additives in syntrophic, metabolic, catalytic, enzymatic, and cation exchange activities of the anaerobic digestion process are highlighted. The synergistic effect of bio-additives and operational factors of the bioelectrochemical system is explored. It is elucidated that a bioelectrochemical system coupled with nanomaterial additives can increase biogas–methane potential compared to anaerobic digestion. Therefore, the prospects of a bioelectrochemical system for wastewater require research attention.

/pdf/application-of-bioelectrochemical-systems-and-anaerobic-2v4a946y.pdf

Application of Bioelectrochemical Systems and Anaerobic Additives in Wastewater Treatment: A Conceptual Review

Because of the complexity of gear working condition, there are non-linear relationship between characteristic parameters and fault types. This paper proposes to apply the Support Vector Machine to set up the nonlinear mapping to solve the difficulties of gear fault diagnosis. Taking a certain gearbox fault signal acquisition experimental system for instance, Matlab software and its neural network toolbox are used to model and simulate. The simulation result shows the founded model has preferable learning and generalization capabilities, which performs effectively in the common gear fault diagnosis and it can identify various types of faults stably and accurately.

Jia Li Tang

Papers

Gear Fault Diagnosis with Support Vector Machine