Simultaneous Bioelectricity Generation Research Articles

Wastewater remediation and bioelectricity generation in dual chambered salt bridge microbial fuel cell: A mini‐review

AbstractThe purpose of this article is to assess the feasibility analysis of microbial fuel cells (MFCs), particularly in the configuration of dual chamber salt bridge microbial fuel cell (DCSB‐MFC), as a promising approach for simultaneous bioelectricity generation and wastewater remediation. The application of a salt bridge presents an economically viable alternative to the use of a proton exchange membrane, which is known for its high cost, in the construction of MFCs. This arrangement has been demonstrated to offer significant benefits in terms of enhancing the performance of new elements and evaluating operational parameters. However, it also encounters issues related to the total internal resistance (Rint) of the MFCs as well as power density (P). In addition, it has been found that traditional packing materials such activated carbon and gravel demonstrate poor permeability, internal resistance, and slow biofilm growth. Furthermore, there is a necessity to search for electrodes that possess high resistance to corrosion and are cost‐effective to achieve optimal bioelectricity generation. Therefore, this article aims to emphasize the research areas that require attention. By addressing these areas, the actual implementation of this configuration can be brought closer to practical implementation.

Variation of graphene/titanium dioxide concentration as electrocatalyst for an oxygen reduction reaction in constructed wetland-microbial fuel cells

Constructed wetlands-microbial fuel cells (CW-MFC) are an innovative technology used for simultaneous bioelectricity generation and wastewater treatment. This is possible due to the installation of macrophytes in an electrode configuration, in which electroactive microorganisms use organic substrates as biofuel. One way to improve the electrochemical performance of CW-MFCs is through the impregnation of cathodic electrocatalysts. Therefore, in this study the bioelectricity production capacity of CW-MFCs was evaluated from the oxygen reduction reaction (ORR). For this study, the concentrations 0 (CW-MFC1), 0.5 (CW-MFC2), and 1 mg/cm2 (CW-MFC3) of graphene/titanium dioxide (G/TiO2) as electrocatalyst on the cathodes were evaluated. Using the Koutecky-Levich analysis, it was determined that the ORR transfer mechanism arises via a 4-electron pathway. The electrokinetic parameters of Tafel slope, charge transfer coefficient, and exchange current density determined the efficiency of the ORR, registering 92 mV/dec, 0.93 (α), and 2.30 x10-3 mA/cm2, respectively for CW-MFC3. The highest electrochemical performance was obtained at a concentration of 1 mg/cm2 (CW-MFC3) of G/TiO2, generating 144 mW/m2 of power density, 157 Ω of internal resistance, −150 mV of anodic potential, and 383 mV of cathodic potential. The surface modification carried out on the cathodes resulted in a catalytic increase in the ORR.

Bioelectricity generation from corn plant microbial fuel cell (PMFC) using natural bamboo charcoal as electrodes and Shewanella oneidensis

Environmentally friendly energy is a burning issue in recent years due to the protection of the earth and the sustainable future. In this study, simultaneous bioelectricity generation and corn (Zea mays L.) harvesting have been carried out by using natural bamboo charcoal as electrode materials. Cathode was placed as parallel (horizontal) to and vertical to the surface, respectively in two corn plant microbial fuel cells. Another 2 cells have been prepared as blank PMFC but to compare the effects of plants. Voltage data has been measured once in a day for a total of 70 days (10 weeks). Weather factors such as mean temperature, solar radiation, precipitation were used to see the effects of these parameters in bioelectricity generation. It was noted that horizontal placement of cathode was better than that of vertical placement for power output (320 mW/m2 and 128 mW/m2, respectively). The peak voltage was around 980 mV, 120 mV (blank) for horizontal and 620 mV and 90 mV(blank)for vertical placement when the resistance was 100 Ω. Solar radiation and precipitation were more prominent weather factors for bioelectricity generation than the mean temperature. It was proved that simultaneous bioelectricity generation and corn harvesting can be possible by using plant microbial fuel cells.

Simultaneous removal of sulfide and bicarbonate from synthetic wastewater using an algae-assisted microbial fuel cell

ABSTRACT The anaerobic digestion (AD) process is one of the most practiced technologies for the remediation of organic waste and maximization of energy recovery in terms of biogas or biomethane. The presence of other gaseous components in biogas, e.g. CO2 and H2S, often makes its direct application in engines and electricity production unsuitable. This work aimed to develop and utilize an algae-assisted microbial fuel cell (AMFC) for the purification of biogas by removing both CO2 and H2S and simultaneous bioelectricity generation. In addition to biogas clean-up, elemental sulfur recovery and CO2 utilization for algae cultivation add value to the proposed AMFC process. Experiments were performed with both sulfide and bicarbonate in their dissolved form, in the respective anodic and cathodic chambers of the AMFC. The sulfide concentration was varied from 100 to 800 mg/l and the AMFC exhibited a sulfide removal efficiency exceeding 97% at all concentrations tested. The process efficiency dropped, however, at sulfide concentrations above 300 mg/l in terms of both sulfide removal and power output. The AMFC performed best at 400 mg/l sulfide by exhibiting a power density of 24.99 mW/m3 and sulfide removal efficiency of 98.87%. The system exhibited columbic efficiency (CE %) in the range of 7.85–80%. The total alkalinity representing CO2, carbonate and bicarbonate levels in the algae-based system was reduced by 49.54%. The electrical energy recovered from the AMFC was 0.1 kWh/m3 and the total energy recovery, which is the sum of the electrical and algal lipid energy, amounted to 7.25 kWh/m3.

Development of microbial fuel cell integrated constructed wetland (CMFC) for removal of paracetamol and diclofenac in hospital wastewater

Hospital wastewater management has become a significant concern across the globe due to the presence of pharmaceutically active compounds (PhACs) and other toxic substances, which can potentially disrupt ecosystems. The presence of recalcitrant PhACs in hospital wastewater increases the difficulty level for conventional wastewater treatment systems. Furthermore, incorporating advanced oxidation-based treatment systems increase capital and operation costs. To reduce treatment costs, low-cost innovative technology, i.e., composite constructed wetland and microbial fuel cell system (CMFC), has been developed for higher treatment efficiency of PhACs in hospital wastewater along with simultaneous bioelectricity generation as an additional outcome. In this study, influencing operating parameters, such as initial chemical oxygen demand (COD), electrode spacing, and substrate-to-water-depth ratio, were optimized for two plant species: water hyacinth (WH) and duckweed (DW). The optimized systems were run in batch and continuous mode for WH-CMFC and DW-CMFC to treat synthetic hospital wastewater with paracetamol and diclofenac, and the bioelectricity generation was monitored. DW-CMFC system depicted better treatment efficiency and voltage generation as compared to WH-CMFC. In continuous mode, the DW-CMFC system exhibited a removal of 95.3% COD, 97.1% paracetamol, and 87.5% diclofenac. WH-CMFC and DW-CMFC achieved power densities of around 21.26 mW/m2 and 42.93 mW/m2, respectively. The fate of PhACs during and after treatment and toxicity analysis of the transformation products formed were also carried out. Higher bio-electricity generation and efficient wastewater treatment of the DW-CMFC make it a sustainable option for hospital wastewater management.

Nano-hydroxyapatite/carbon nanotube: An excellent anode modifying material for improving the power output and diclofenac sodium removal of microbial fuel cells

Anode material and surface properties have a crucial impact on the performance of MFCs. Designing and fabricating various modified carbon-based anodes with functional materials is an effective strategy to improve anode performance in MFCs. Anode materials with excellent bioaffinity can promote bacterial attachment, growth, and extracellular electron transfer. In this study, positively charged nano hydroxyapatite (nHA) with remarkable biocompatibility combined with carbon nanotubes (CNTs) with unique structure and high conductivity were used as anode modifying material. The nHA/CNTs modified carbon brush (CB) exhibited improved bacteria adsorption capacity, electrochemical activity and reticular porous structure, thus providing abundant sites and biocompatible microenvironment for the attachment and growth of functional microbial and accelerating extracellular electron transfer. Consequently, the nHA/CNTs/CB-MFCs achieved the maximum power density of 4.50 ± 0.23 mW m−2, which was 1.93 times higher than that of the CB-MFCs. Furthermore, diclofenac sodium (DS), which is a widely used anti-inflammatory drug and is also a persistent toxic organic pollutant constituting a serious threat to public health, was used as the model organic pollutant. After 322 days of long-term operation, enhanced diclofenac sodium removal efficiency and simultaneous bioelectricity generation were realized in nHA/CNTs/CB-MFCs, benefiting from the mature biofilm and the diverse functional microorganisms revealed by microbial community analysis. The nHA/CNTs/CB anode with outstanding bioaffinity, electrochemical activity and porous structure presents great potential for the fabrication of high-performance anodes in MFCs.

Biodegradation of Reactive Red 195 azo dye and Chlorpyrifos organophosphate along with simultaneous bioelectricity generation through bacterial and fungal based biocathode in microbial fuel cell

A laboratory-scale dual-chambered bioanode and biocathode based Microbial Fuel Cell (MFC) was employed in the biodegradation of a dye Reactive Red 195 (RR195) and pesticide chlorpyrifos using bacterial and fungal strains. UV-spectrophotometery and and fourier transform infrared (FTIR) data showed removal rates of almost; 100% for both dye (150 mg/L) and pesticide (50 mg/L) with 70 and 81% Chemical Oxygen Demand (COD) in 18 h and 48 h respectively. Bio-electrochemical degradation of said pollutants was also coupled with simultaneous generation of electricity. The maximal cell potential was recorded to be 635 and 706 mV in bacterial and fungal MFC systems with corresponding power densities of 224.01 and 276.9mWm−2 respectively. Electrochemical performance of MFC reactors in term of cyclic voltammetry (CV) and chronoamperometry (CA) showed maximum electron transfer of 122 and 27.35 mA (applied voltage of −1 to +1 V (CV)) and current densities of 13.8 and 10.66mAcm−2 (CA) in the cathodic compartment where degradation of pollutants accomplished. The reactor was also tested for the simultaneous biodegradation of RR 195 dye in real wastewater along with bioelectricity production. The overall COD and colour removal efficiency was 72 %, and 95 % with concurrent increase in TDS, EC and with a maximum power density output of 519.49 mWm−2. The outcomes of this study revealed that MFC technology is highly effective in the treatment of ecological hazardous aromatic pollutants such as dyes (i.e., RR 195) and pesticides (e.g., chlorpyrifos) and for harnessing energy.

A novel sulfur-driven autotrophic denitrification coupled with bio-cathode system for bioelectricity generation and groundwater remediation.

This study explored the feasibility of treating wastewater using sulfur-driven autotrophic denitrification (SAD) coupled with the bio-cathode of microbial fuel cell (MFC), focusing on simultaneous bioelectricity generation, denitrification, and desulphurization. A maximum output voltage of 360 mV was obtained with a power generation cycle of 25 h when simulated wastewater with 100.0 mg/L of each NO3--N and S2--S was employed as the influent in the SAD-BMFC. Compared with solo SAD or MFC, SAD-BMFC obtained a higher NO3--N removal rate (E12 h = 87.7%, E24 h = 100%), and less NO2--N accumulation. S2--S of the influent was almost completely removed, oxidized to S0-S (88.6-90.2 mg/L) and SO42--S (9.8-11.4 mg/L). The reaction system achieved self-balance of acidity-alkalinity (pH 7.05-7.35). The SAD process was the main pathway for NO3--N removal (80.2%) and a smaller proportion of electrons came from the bio-cathode. This study effectively combined SAD with a bio-cathode system for simultaneous energy harvest and bio-enhanced remediation of groundwater contaminated by both NO3--N and S2--S.

Innovative constructed wetland coupled with microbial fuel cell for enhancing diazo dye degradation with simultaneous electricity generation

A novel earthen separator-based dual-chambered unplanted core of constructed wetland coupled with microbial fuel cell was developed for studying the microbe-material interaction and their effect on treatment performance and electricity generation. The constructed wetland integrated microbial fuel cell was evaluated for the degradation of high molecular weight diazo Congo red dye as a model pollutant. The system exhibited 89.99 ± 0.04% of dye decolorization and 95.80 ± 0.71% of chemical oxygen demand removal efficiency from an initial concentration of 50 ± 10 mg/L and 750 ± 50 mg/L, respectively. Ultraviolet–Visible spectrophotometric and gas chromatography-mass spectrometric analysis revealed naphthalene and phenol as mineralized products. The developed system achieved high power density and current density generation of 235.94 mW/m3 and 1176.4 mA/m3, respectively. Results manifested that dual-chambered constructed wetland coupled with microbial fuel cell has a high capability of dye decolorization and toxicity abatement with appreciable simultaneous bioelectricity generation owing to the significantly low internal resistance of 100 Ω.

Polypropylene biofilm carrier and fabricated stainless steel mesh supporting activated carbon: Integrated configuration for performances enhancement of microbial fuel cell

The mass transfer resistance at the anode and the reduction of oxygen at the cathode are currently perceived as two major bottlenecks of microbial fuel cells. To overcome these issues, an integrated configuration was developed for performances enhancement on simultaneous bioelectricity generation and wastewater treatment in single chamber up-flow membrane-less microbial fuel cell (UFML-MFC). Polypropylene biofilm carriers were used as anodic packing materials and fabricated stainless steel mesh holder supporting activated carbon flakes (CF/SM) was employed as biocathode configuration in this study. The employments of polypropylene carriers and CF/SM enhanced not only the active surface area and microbial adhesion, but also the mass transfer of MFC system. The maximum output voltage, power and current generation achieved in this system were 615 mV, 162.59 mW/m2 and 468.74 mA/m2, respectively. In terms of wastewater treatment performance, UFML-MFC achieved 85.6% and 95.7% of COD and NH4+ removal, respectively. The COD reduction in closed circuit was 9.87% better than open circuit due to stimulation of electrochemical-active bacteria for electron transfer to the anode, which favoured organic matter degradation. The enrichment of electrogenic bacteria at A3, which was largest electrode spacing (23 cm) in the system resulted a higher voltage and power output compared to A1 (11 cm) and A2 (17 cm). Besides, the energy performances of this MFC system were also evaluated based on NERs (1.074 kWh/kg COD), NERv (22.86 Wh/m3) and CE (10.42%).

Innovative baffled microbial fuel cells for azo dye degradation: Interactive mechanisms of electron transport and degradation pathway

Two membrane-less baffled microbial fuel cells (BMFCs) were developed for non-dye (BMFC1) and dye degradation (BMFC2) investigations along with simultaneous bioelectricity generation. The influence of salinity, organic loading, circuit connection, aeration rate, dye concentration and addition of intermediates on BMFCs performances were evaluated systematically. The increase of salinity by 3-fold (0.39 g/L of NaCl) lowered the internal resistance of BMFC1 system by 38%–620 Ω, and the power density increased 49% to 10.55 ± 0.86 mW/m2. While the further increase of salinity (10-fold) adversely affected BMFC1. The power performance of BMFC1 improved with higher organic loading. Whereas, the increment in organic loading enhanced the decolourisation efficiency but deteriorated the power performance of BMFC2 ascribed to the competition between New Coccine (NC) molecules and anode for electrons. This finding corroborates that NC was a preferable electron acceptor than the anode. The addition of 50 mg/L NC increased the power density by 53% to 12.40 ± 1.60 mW/m2, which revealed that NC decolourised intermediates could act as the electron mediator, hence led to the increase of power performance. The electron-mediating mechanism of NC decolourised intermediate, 1-amino-2-naphthol-6,8-disulfonate as electron shuttle was unveiled. The in-depth understanding of the mechanisms involved in dye degradation in MFCs was presented, where a comprehensive degradation pathway of NC was proposed based on the intermediates identified via UV–Visible spectra, Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and gas chromatograph-mass spectrometer (GC-MS) analyses.

Simultaneous bioelectricity generation and water desalination using Oscillatoria sp. as biocatalyst in photosynthetic microbial desalination cell

Globally, the scarcity of drinking water has triggered the researchers towards the development of desalination techniques to turn up saline water into potable. Microbial Desalination Cell (MDC) is a novel green technology that shows potential approach for desalination along with electricity generation and wastewater treatment. However, the expensive catholyte/catalyst in the cathode side has limited the MDC for real time application. Hence, the main objective of this work was to investigate the electricity generation during dairy wastewater treatment and desalination efficiency using biocathode (Oscillatoria sp.) in the MDC. The results showed that the maximum open circuit voltage of 652 ± 10 mV, COD removal efficiency of 80.2 ± 0.5% and desalination efficiency of 65.8 ± 0.5%, were achieved respectively. The effect of saline water concentration was investigated and the performance of MDC was compared with real (sea) water. This study demonstrated that Oscillatoria sp. could be used as a potential biocatalyst in the cathode chamber for enhancing salinity removal along with electricity generation and wastewater treatment in the MDC.

Organic matter removal and nitrogen transformation by a constructed wetland-microbial fuel cell system with simultaneous bioelectricity generation

Microbial fuel cells integrated into constructed wetlands have been previously studied. Nevertheless, their application as a suitable treatment for wastewater is still in the developmental stage.In this context, the aim of this study was to evaluate organic matter removal and nitrogen transformation by a microbial fuel cell integrated into a constructed wetland (CWMFC). To accomplish this, three experimental systems were operated under batch-mode conditions over 170 days: i) one was planted with Schoenoplectus californicus (P-CWMFC); ii) another was unplanted (NP-CWMFC); and iii) the third system did not have any electrodes (CW) and was used as a control.Chemical oxygen demand (COD) removal efficiency ranged between 74–87%, 69–81% and 62–72% for the P-CWMFC, NP-CWMFC and CW systems, respectively, with organic loading rates (OLR) ranging from 4.8 to 7.9 g COD/m2 d. NH4+-N removal efficiency exceeded 98%, 90% and 83% for P-CWMFC, NP-CWMFC and CW, respectively. Wastewater treatment performance was improved due to anaerobic oxidation that occurred on the anodes. Organic matter removal was 18% higher in closed-circuit mode than in open-circuit mode in both integrated systems (P-CWMFC and NP-CWMFC), and these differences were significant (p < 0.05). With respect to the performance of microbial fuel cells, the maximum power density (8.6 mW/m2) was achieved at an organic loading rate of 7.9 g COD/m2 d with an internal resistance and coulombic efficiency of 251 Ω and 2.4%, respectively. The results obtained in this work can provide positive impacts on CW development by enhancing anaerobic degradation without forced aeration.

Statement of Retraction

This article refers to:Simultaneous bioelectricity generation and remediation of sulfide-contaminated tidal flat through sediment microbial fuel cell (SMFC)

Simultaneous bioelectricity generation and remediation of sulfide-contaminated tidal flat through sediment microbial fuel cell (SMFC)

(2020). Simultaneous bioelectricity generation and remediation of sulfide-contaminated tidal flat through sediment microbial fuel cell (SMFC). Energy Sources, Part A: Recovery, Utilization, and Environmental Effects. Ahead of Print.

Simultaneous bioelectricity generation and pollutants removal of sediment microbial fuel cell combined with submerged macrophyte

A submerged macrophyte sediment microbial fuel cell (SP-SMFC) was constructed in this study. Ceratophyllum demersum L., Vallisneria natans, Hydrilla verticillate were chosen as the submerged plants to form cer-SMFC, val-SMFC, hyd-SMFC systems. Plant groups showed the advantage of bioelectricity generation and pollutants removal compared with the unplanted system. The cer-SMFC group stood out with the maximum power density as 24.56 mW m−2 and the average pollutants removal in overlying water (COD: 81.16%, TN: 65.27%, TP: 79.10%) and in sediments (TN: 26.40%, TP: 21.79%). The determination of root exudates and radial oxygen loss (ROL) demonstrated that C. demersum L. was superior to other studied submerged macrophytes. More root exudates may contribute to an increase in available substrates for electrochemically active bacteria and other microorganisms. Higher enzyme activities were obtained in three SP-SMFCs (especially in cer-SMFC). ATPase and APA activities in cer-SMFC group were increased by over 40% compared with the control. The results indicated that the presence of plants enhanced the microorganism activities, thereby improving bioelectricity generation and pollutants removal. This study will facilitate the application of SP-SMFC technology as an alternative for in situ remediation of polluted sediments.

Simultaneous bioelectricity generation, desalination, organics degradation, and nitrogen removal in air–cathode microbial desalination cells

In this study, a three-chamber air–cathode microbial desalination cell (AMDC) was constructed using activated sludge as the inoculating microbial source and carbon cloth as the electrode. The simultaneous bioelectricity generation, desalination, degradation of organic compounds, and nitrogen removal in the AMDC having different electrode spacings (16, 12, and 8 cm) provided an insight into the microbial community. The experimental results showed that with a gradual decrease in the electrode spacing, electricity production and desalination performance first increased and then decreased. While AMDC1 with 16 cm electrode spacing became active faster than other cells and reached a peak voltage of 598 mV on the tenth day, AMDC2 with 12 cm electrode spacing showed the best start-up performance with a maximum output voltage of 645 mV, maximum power density of 214.7 mW/m3, and minimum resistance of 516.9 Ω. AMDC3 with 8 cm electrode spacing reached a peak voltage of 598 mV, which was between those of AMDC1 and AMDC2. The three AMDCs were run until the end of the cycle, and there was no significant difference in their ammonium removal rate and chemical oxygen demand. For AMDC1–3, the desalination rates were 84.86%, 87.71%, and 83.43%, and the Coulomb efficiencies were 17.29%, 18.60%, and 17.95%, respectively. Further, scanning electron microscopy showed that a large number of microorganisms could attach to the surface of the anode carbon cloth electrode; 16S rRNA sequencing showed that the typical electrogenic microbial communities were Bacillus (11.6%) and Arcobacter (9.6%). As the poor performance of the AMDC was primarily due to a lack of electrogenic microorganisms in the active function of the anode chamber, screening the functional microorganisms provided a reference for optimizing and amplifying the application of microbial desalination cells in practical research.

Evaluation of integrated UFCW-MFC reactor for azo dye wastewater treatment and simultaneous bioelectricity generation

Evaluation of integrated UFCW-MFC reactor for azo dye wastewater treatment and simultaneous bioelectricity generation

Bioelectricity generation and remediation of sulfide contaminated tidal flat sediment

A dramatic decrease in the catch of shellfish has been observed due to the high amount of Acid Volatile Sulfide (AVS) in the tidal flats in Japan. In the current study, an evaluation of simultaneous bioelectricity generation and remediation of sulfide contaminated tidal flat sediment has been done. The sediment samples collected from Tokyo Bay and Yamaguchi Bay, Japan, have been used in the laboratory test. A 2 L cylindrical shaped Sediment Microbial Fuel Cell (SMFC) has been used to evaluate the remediation of both sediment samples in the laboratory. Three different electrode materials carbon felt, carbon fiber and bamboo charcoal were used in the experiments to compare their efficiency to reduce the AVS from the sediment and generate bioelectricity. It was observed that the AVS reduction was higher at 5 cm depths for the Tokyo Bay sediment (100%) compared to the Yamaguchi Bay sediment (60%). The larger grain size for the Tokyo Bay sediment was the probable reason for this. The maximum voltage was around 100 and 80 mV for Tokyo Bay and Yamaguchi Bay, respectively.

Simultaneous bioelectricity generation from cost-effective MFC and water treatment using various wastewater samples

Worldwide, the requirement of electrical energy has increased with an increase in population. Thus, there is a need to develop an alternative source of sustainable energy, such as microbial fuel cell (MFC). MFC is a better option of energy generation and can provide a renewable resource which utilizes wastewater into power by the help of microorganisms. MFC is one of the advanced methods for treating wastewater and simultaneously producing current and voltage. Dual-chambered MFC was prepared using two plastic boxes (500 ml) by using wastewater as an anolyte. Different types of mediators are used in MFC including methylene blue, potassium ferricyanide, and EDTA to facilitate and higher the efficiency of electron transfer from the MFC to the electrode. Maximum OCV and current output of sample 1 (Budha Talab pond water) were 0.86 V and 75.1 mA and of sample 2 (Jaypee cement plant) were 1.42 V and 122 mA. The maximum current output of sample 3 (sugar industry, sewage waste, NIT canteen) was 1.3 V. Various physiochemical parameters such as dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) were analyzed which affect the power output. The obtained result concluded that wastewater should be feed at a certain time interval to avoid the loss of substrate for organisms in the anodic chamber which lead to the death of themicroorganism. Among all, sugar industry wastewater has a high potential for power generation as their physiochemical results are suitable for better power output.