Cathodic Electron Acceptor Research Articles

In situ activation of peroxymonosulfate with bioelectricity for sulfamethoxazole sustainable removal

Conventional electrochemical activation of peroxymonosulfate (PMS) is not very cost-effective and practical by the excessive input of energy. The electricity generated by photosynthetic microalgae fuel cells (MFCs) is utilized to activate PMS, which would achieve the combination of green bioelectricity and advanced oxidation processes for sustainable pollutants degradation. In this study, a novel dual-chamber of MFCs was constructed by using microalgae as anode electron donor and PMS as cathode electron acceptor, which was operating under both close-circuit and open-circuit conditions. Under close-circuit condition, 1–12 mM PMS in cathode was successfully in situ activated, where 32.00%–99.83% of SMX was removed within 24 h, which was about 1.21–1.78 times of that in the open-circuit of MFCs. Meanwhile, a significant increase in bioelectricity generation in MFCs was observed after the accumulation of microalgae biomass (4.65–5.37 mg/L), which was attributed to the efficient electron separation and transfer. Furthermore, the electrochemical analysis demonstrated that SMX or its products were functioned as electronic shuttles, facilitating the electrochemical reaction and altering the electrical capacitance. The quenching experiments and voltage output results reflected that complex active radical (SO4⋅-, ⋅OH, and 1O2) were involved in SMX removal. Seven degradation products of SMX were detected and S–N bond cleavage was the main degradation pathway. Predicted toxicity values calculated by ECOSAR program showed that all the products were less toxic or nontoxic. Finally, the density functional theory (DFT) calculations revealed that the O and N atoms on SMX were more susceptible to electrophilic reactions, which were more vulnerable to be attacked by reactive species. This study provided new insights into the activation of PMS by bioelectricity for SMX degradation, proposing the mechanisms for PMS activation and degradation sites of SMX.

S-scheme N-doped carbon dots anchored g-C3N4/Fe2O3 shell/core composite for photoelectrocatalytic trimethoprim degradation and water splitting

Photoelectrocatalysis is a promising technique for energy conversion and environmental treatment. This study describes the photoelectrochemical (PEC) degradation of trimethoprim and hydrogen evolution using a photoanode prepared by N-doped carbon dots (NCD) incorporated g-C3N4/α-Fe2O3 (CNFO) shell/core nanocomposite. The electrochemical analysis reveals that the photocurrent density of NCD@CNFO photoanode reached 3.07 mA cm−2 at 1.6 V vs. NHE, which is 4 and 15 times greater than that of CNFO and intact α-Fe2O3, respectively. In the presence of peroxymonosulfate (PMS), the NCD@CNFO photoanode enabled 95 % and 90 % of trimethoprim (TMP) degradation in aqueous solution and lake water, respectively. Hydrogen generation coupled with TMP degradation was also observed in the PEC system, where the H2 generation rate was 550 µmol cm−2 h−1. Both superoxide (•O2−) and hydroxyl (•OH) radicals played a significant role in the degradation of TMP. The achievements could be assigned to the excellent photoabsorption and electron transfer properties of NCD, which enhanced the PEC activity of CNFO by enabling the S-scheme heterojunction to reduce electron-hole recombination. Moreover, PMS served as a cathodic electron acceptor to improve the catalytic properties of NCD@CNFO photoanode, demonstrating its contribution to both water treatment and hydrogen production. Such superior efficiency offers great potential to develop a PEC system using carbon dots/semiconductor hybrid catalysts for antibiotic degradation and synchronous photocatalytic H2 evolution from wastewater, providing an alternative solution to environmental pollution and energy crisis issues.

Bioelectrocatalytic Reduction of Tellurium Oxyanions toward Their Cathodic Recovery: Concentration Dependence and Anodic Electrogenic Activity

Regulation on the usage of trace toxic metals and their depletion necessitates their detoxification/recovery. Tellurium scarcity in the environmental matrix and its multitude applications depicts its worth for recovery from toxic ionic forms. Bioelectrochemical systems (BESs) facilitate metal detoxification/recovery. In this study, a novel double-chambered BES coupled with a biotic anode and abiotic cathode was operated using varied concentrations of toxic tellurite oxyanions (Te4+) as a terminal cathodic electron acceptor (CEA), facilitating bioelectroreduction of Te4+ to elemental tellurium (Te0) (cathode) and wastewater treatment (anode). Results depicted a Te0 element recovery of 45.3% with a tellurite removal of 54.7% in the abiotic cathode with a simultaneous substrate degradation of 67% in the biotic anode. The cathodic Te0 recovery with increased CEA-dependent electrotrophy has proportionally influenced the anodic microbial enzymatic activity. Bioelectrochemical characterization showed an increased anodic electrogenic performance relative to the increased CEA concentrations, achieving a comparatively higher power density of 0.044 W/m2 in the Te-C condition. Recovered Te0 samples were analytically characterized for structural/compositional functionalities and speciation variations to confirm the presence of Te0 element and its crystalline nature at the cathode. The study provided the application feasibility of BESs in favoring Te detoxification/recovery at the abiotic cathode, while regulating the anodic microbial electron/enzymatic/metabolic flux.

Bioelectricity production and shortcut nitrogen removal by microalgal-bacterial consortia using membrane photosynthetic microbial fuel cell

Membrane photosynthetic microbial fuel cell (MPMFC) utilizes O2, NO3− and NO2− as cathodic electron acceptors, enabling simultaneous treatment of nitrogen, CO2 and organic carbon in the cathode compartment. In this work, development of a novel cathodic process with in situ nitritation via microalgal photosynthesis during the light period is reported for achieving shortcut nitrogen removal (SNR) from ammonium-rich wastewater. Moreover, a tubular low-cost ceramic membrane was used to separate and recycle the microalgal-bacterial biomass to the cathode compartment during the continuous operation. The influence of NH4+ concentration and ratio of chemical oxygen demand to total nitrogen on the MPMFC performance was examined. Denitritation under dark and anoxic conditions occurred due to denitrifying bacteria (DNB) subsequent to nitritation under light and aerobic conditions by ammonia-oxidizing bacteria (AOB) in the consortia. Final concentrations of NH4+ and NO2− in the effluent of 0.10 mg NH4+-L−1 and 0.02 mg NO2−-L−1, respectively, were obtained using MPMFC which resulted in a nitrogen removal efficiency of 99 ± 0.5%. The maximum electricity production achieved using the MPMFC was 56 ± 0.1 mA. This study demonstrated that combining microalgal photosynthesis, nitritation and denitritation in the cathode compartment of MPMFC is advantageous for avoiding the cost due to external aeration and organic carbon source necessary for ammonium removal as well as utilization of NO2− or NO3− as an electron acceptor.

Complete solar-driven dual-photoelectrode fuel cell for water purification and power generation in the presence of peroxymonosulfate

This study reports the development of complete solar-driven dual-photoelectrode fuel cell (PFC) based on WO3 photoanode and Cu2O photocathode with peroxymonosulfate (PMS) serving as cathodic electron acceptor. As indicated by photoelectrochemical measurements, the PMS was able to improve thermodynamic properties of photocathode, achieving an increased open circuit potential from 0.42 V to 0.65 V vs standard hydrogen electrode (SHE). Under simulated sunlight irradiation (~100 mW cm−2), the maximum power density of 0.12 mW cm−2 could be obtained at current density of 0.34 mA cm−2, which was 8.57 times of that produced by PFC without PMS (0.014 mW cm−2). Correspondingly, adding PMS (1.0 mM) increased overall removal efficiency of 4-chlorophenol (4-CP) from 39.8% to 96.8%, accounting for the first-order kinetic constant (k=0.056 min−1) being 6.67 times of that in the absence of PMS (k=0.0084 min−1). Radical quenching and electron spin-resonance (ESR) results suggested the contribution of free radicals (•OH and SO4•-) and non-radical pathway associated with direct activation of PMS by Cu2O photocathode. Fourier transformed infrared (FTIR) analysis confirmed the strong non-radical interaction between Cu2O photocathode and PMS, resulting in 4-CP removal via activation of PMS by surface complex on Cu2O. The proof-in-concept complete solar-driven dual-photoelectrode fuel cell may offer an effective manner to realize water purification and power generation, making wastewater treatment more economical and more sustainable.

Impact of cathodic electron acceptor on microbial fuel cell internal resistance

Ferricyanide is often used in microbial fuel cells (MFCs) to avoid oxygen intrusion that occurs with air cathodes. However, MFC internal resistances using ferricyanide can be larger than those with air cathodes even though ferricyanide results in higher power densities. Using a graphite fiber brush cathode and a ferricyanide catholyte (FC-B) the internal resistance was 62 ± 4 mΩ m2, with 84 ± 8 mΩ m2 obtained using ferricyanide and a flat carbon paper cathode (FC-F) and only 51 ± 1 mΩ m2 using a 70% porosity air cathode (A-70). The FC-B MFCs produced the highest maximum power density of all configurations examined: 2.46 ± 0.26 W/m2, compared to 1.33 ± 0.14 W/m2 for the A-70 MFCs. The electrode potential slope (EPS) analysis method showed that electrode resistances were similar for ferricyanide and air–cathode MFCs, and that higher power was due to the larger experimental working potential (500 ± 12 mV) of ferricyanide compared to the air cathode (233 ± 5 mV).

Effect of Organic Concentration in the Anode and Cathode on Bioelectricity Generation and Denitrification in a Single-Cathode Three-Anode Microbial Fuel Cell

AbstractAn innovative single-cathode three-anode microbial fuel cell (SCTA-MFC) was constructed, using sodium acetate as the anode organic substrate and nitrate as the cathode electron acceptor. It...

Enhancement of biological oxygen demand detection with a microbial fuel cell using potassium permanganate as cathodic electron acceptor

When dual-chamber microbial fuel cell (MFC) is used to detect biochemical oxygen demand (BOD), dissolved oxygen is traditionally used as cathodic electron acceptor. The detection limit of this MFC-based BOD biosensor is usually lower than 200 mg/L. In this paper, the startup of MFC-based BOD biosensor was researched and the external resistor of MFC was optimized. Results showed that the MFC started up with the dissolved oxygen as cathodic electron acceptor within 10 d, and the external resistor was optimized as 500 Ω to ensure the maximum output power of MFC. Dissolved oxygen and potassium permanganate (KMnO4) were used as cathodic electron acceptor to run MFC for detection of wastewater BOD, and the performances of two kinds of BOD biosensors were compared. The MFC-based BOD biosensor using KMnO4 (10 mmol/L) as cathodic electron acceptor exhibited an excellent performance, compared with that using dissolved oxygen. The upper limit of BOD detection was greatly broadened to 500 mg/L, the response time was shortened by 50% for artificial wastewater with a BOD of 100 mg/L, and the relative error of BOD detection was reduced to less than 10%. The MFC-based BOD biosensor using KMnO4 as cathodic electron acceptor showed a better linear relationship (R2 > 0.992) between the electric charge and BOD concentration within a BOD range of 25–500 mg/L. The MFC-based BOD biosensor using the KMnO4 as cathodic electron acceptor is promising with a better application prospect.

Wastewater treatment by microbial fuel cell coupled with peroxicoagulation process

A microbial fuel cell is a rapidly growing, eco-friendly and green technology. As per this technology, the microorganisms are employed to convert the chemical energy stored in the biodegradable portion of organic matter into direct electric current by simultaneously treating the wastewater. In this study, dual-chambered H-type mediator-less and membrane-less microbial fuel cell was operated and was optimized using synthetic wastewater as a substrate. The influence of various factors such as cathodic electron acceptors, electrode configuration, electrode spacing on chemical oxygen demand removal and current output were investigated. The maximum current of 1.72 mA was obtained using synthetic wastewater with potassium permanganate as effective catholyte, electrode spacing of 2 cm from the salt bridge and surface area of 98 cm2. This study also investigated the effect of substrate in the optimized MFC by applying different real wastewaters (municipal wastewater, dairy wastewater, cassava wastewater) and found a superior performance by dairy wastewater with maximum current output of 5.23 mA and chemical oxygen demand removal of 94%. Electron microscopic observations revealed the development of biofilm on the electrode surface, which was responsible for biocatalytic activity in the microbial fuel cell during the operation. The current generated using microbial fuel cell was supplied to peroxicoagulation process and was used for the removal of rhodamine B dye. Decolorization of 98% achieved by the novel microbial fuel cell-coupled peroxicoagulation system. The novel microbial fuel cell-coupled peroxicoagulation is an energy-efficient as well as cost-effective technique.

Improved bioelectricity production using potassium monopersulfate as cathode electron acceptor by novel bio-electrochemical activation in microbial fuel cell

Potassium monopersulfate (PMS) without a catalyst as cathode electron acceptor was first established to improve the electricity generation performance of a microbial fuel cell (MFC) in this study. The work investigated the performance with pure PMS (PPMS) and compound PMS (CPMS). The concentration and initial pH of PMS had an effect on the electricity generation, which increased with higher PMS concentration and lower catholyte pH. In the PPMS-MFC system, the maximum voltage (0.972 V), power density (16.37 W/m3), optimal exchange current density (2.000 A/m3) and minimum polarization impedance (Rp: 97.33 Ω) were reached at 10 mM PMS and pH 3.0. However, the maximum power density (8.60 W/m3) was exhibited at 70 mM PMS and pH 3.0 in the CPMS system. Additionally, high COD removals of 99.41% and 98.71% in anode chambers were obtained in the two systems, respectively. Sulfate radicals (SO4—) and hydroxyl radicals (OH) played significant roles in the PPMS-MFC, while HClO was also a contributor in addition to SO4— and OH in the CPMS-MFC. Furthermore, SO4— and OH was generated in situ in the cathode to promote the reduction reaction. The inorganic anion had different effects on electricity generation. Finally, while energy was recovered, rhodamine B (RhB) was added to the cathode chamber and then removed successfully in PPMS-MFC system. This work confirmed that only PMS could be activated by bio-electrochemical method, which is an energy-saving, environmentally friendly and effective activation approach, and thus, it could be used as an efficient acceptor in a MFC.

High-concentration nitrogen removal coupling with bioelectric power generation by a self-sustaining algal-bacterial biocathode photo-bioelectrochemical system under daily light/dark cycle

High-concentration nitrogen removal coupled with bioelectric power generation in an algal-bacterial biocathode photo-bioelectrochemical system (PBES) was investigated. The PBES can self-sustaining operation with continuous power output under day/night cycle by alternately using photosynthetic dissolved oxygen and nitrate/nitrite as cathodic electron acceptors. The PBES generated a high maximum power of 110mw/m2 under illumination and relatively lower power of 40mw/m2 under dark. The bioelectricity generation was accompanied by high-concentration nitrogen removal in the algal-bacterial biocathode. The NH4N was removed completely within 120 h while maximum NO3N removal efficiency of 86% and maximum total nitrogen removal efficiency of 83% can be reached after 192 h at initial NH4N concentration of 314 mg/L and NO3N concentration of 330 mg/L. Combined processes of bioelectrochemical reduction and algal-bacterial interactions provided multiple approaches for nitrogen removal in the biocathode, including nitrifying using photosynthetic oxygen, bioelectrochemical denitrification using the cathode as electron donor, heterotrophic denitrification using photosynthetically produced dissolved organic matters as carbon source and algal-bacterial uptake. Accelerated nitrogen removal with simultaneously improved cathode performance was observed at high concentration of nitrogen and phosphate buffer due to enhanced algal activities for photosynthetic oxygen release and enhanced algal-bacterial interactions for nitrogen transformation. Addition of external organic carbon negatively affected nitrification and decreased cathode potential due to oxygen consumption by aerobic carbon oxidation but enhanced denitrification due to continuous release of high concentration of photosynthetically produced dissolved organic matters by alga. The PBEC was demonstrated as an energy-saving approach for high-strengthen nitrogenous wastewater treatment.

Enhanced oxytetracycline removal coupling with increased power generation using a self-sustained photo-bioelectrochemical fuel cell

Photo-bioelectrochemical fuel cell (PBFC) represents a promising technology for enhancing removal of antibiotic pollutants while simultaneously sustainable transformation of organic wastes and solar energy into electricity. In this study, simultaneous antibiotic removal and bioelectricity generation were investigated in a PBFC with daily light/dark cycle using oxytetracycline (OTC) as a model compound of antibiotic. The specific OTC removal rate increased by 61% at an external resistance of 50 Ω compared to that in the open-circuit control, which was attributed to bioelectrochemically enhanced co-metabolic degradation in the presence of the bioanode. The OTC removal was obviously accelerated during illumination of cathode in contrast with a dark cathode due to the higher driving force for anodic bioelectrochemical reaction by using photosynthetic oxygen as cathodic electron acceptor during illumination than that using nitrate in dark. The bioelectrocatalytic activity of anodic biofilm was continuously enhanced even at an initial OTC concentration of up to 50 mg L−1. The degradation products of OTC can function as mediators to facilitate the electron transfer from bacteria to the anode, resulting in 1.2, 1.76 and 1.8 fold increase in maximum power output when 10, 30 and 50 mg L−1 OTC was fed to the bioanode, compared to the OTC-free bioanode, respectively. The OTC feeding selective enriched OTC-tolerant bacterial community capable of degrading complex organic compounds and producing electricity. The occurrence of ARGs during bioelectrochemical degradation of OTC was affected more greatly by the succession of the anodic bacterial community than the initial OTC concentration.

Using Low Cost Membrane in Dual-Chamber Microbial Fuel Cells (MFCs) for Petroleum Refinery Wastewater Treatment

There are enormous methods to treat petroleum refinery wastewaters (PRW) that contain water-soluble hydrocarbons which cannot be separated by physical methods. Using microbial fuel cell (MFC) is a new PRW treatment method. Using potassium permanganate as cathodic electron acceptors in the cathode apartment of MFC with cheap proton exchange membrane instead of expensive Nafion was used in this work to treat PRW from Al Dura refinery. Potassium permanganate was used as cathodic electron acceptor to enhance MFC power production. So the effects of potassium permanganate amount on the MFC performance and PRW treatment results were investigated. Maximum power production at the room temperature of 1.0032 W/m2 using 0.125 g/L of permanganate concentration, the maximum COD removal efficiency was 71.24 % during 48 hours.

Integration of Biofuel Cell-Based Self-Powered Biosensing and Homogeneous Electrochemical Strategy for Ultrasensitive and Easy-To-Use Bioassays of MicroRNA.

Biofuel cell (BFC)-based self-powered biosensors have attracted substantial attentions because of their unique merits such as having no need for power sources (only two electrodes are needed). More importantly, in case it can also work in a homogeneous system, more efficient and easy-to-use bioassays could come true. Thus, herein, we proposed a novel homogeneous self-powered biosensing strategy via the integration of BFCs and a homogeneous electrochemical method, which was further utilized for ultrasensitive microRNA (miRNA) detection. To construct such an assay protocol, the cathodic electron acceptor [Fe(CN)6]3- was entrapped in the pores of positively charged mesoporous silica nanoparticles and capped by the biogate DNAs. Once the target miRNA existed, it would trigger the controlled release of [Fe(CN)6]3-, leading to the dramatic increase of the open circuit voltage. Consequently, the "signal-on" homogeneous self-powered biosensor for the ultrasensitive miRNA assay was realized. Encouragingly, the limit of detection for the miRNA-21 assay was down to 2.7 aM (S/N = 3), obviously superior to those of other analogous reported approaches. This work not only provides an ingenious idea to construct the ultrasensitive and easy-to-use bioassays of miRNA but also exhibits a successful prototype of a portable and on-site biomedical sensor.

Hexavalent chromium as a cathodic electron acceptor in a bipolar membrane microbial fuel cell with the simultaneous treatment of electroplating wastewater

Hexavalent chromium wastewater is produced in electroplating processes and the heavy metal industry, highlighting the need for an environmentally friendly treatment and the recovery of chromium. This study compared the performance of microbial fuel cells implemented with a proton exchange membrane (PEM-MFC) and a bipolar membrane (BPM-MFC) using hexavalent chromium from electroplating wastewater as the catholyte. The removal of hexavalent chromium and simultaneous bioelectricity generation were enhanced significantly using a BPM. On the other hand, in the PEM-MFC, the lower pH of the electroplating wastewater (pH 1.8) in the cathodic chamber decreased the anodic pH due to proton diffusion through the PEM, and inhibited the bioelectrochemical reaction. Scanning electron microscopy showed that the reduced chromium particles precipitated on the cathode carbon electrode during the MFC operation. The precipitate was identified as amorphous chromium oxide particles by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy.

Performance of Ag2O/Ag Electrode as Cathodic Electron Acceptor in Microbial Fuel Cell

An Ag2O/Ag electrode was prepared through the electrochemical oxidation of sterling silver. This electrode was used as a cathodic electron acceptor in a microbial fuel cell (MFC). The Ag2O/Ag electrode was characterized by scanning electron microscopy, X-ray powder diffraction and linear sweep voltammetry. The maximum voltage output of the MFC with the Ag2O/Ag cathode was maintained at between 0.47 and 0.5 V in 100 cycles, indicating the good regenerative capacity of the Ag2O/Ag electrode. The overpotential loss for silver oxide was 0.021–0.006 V, and the maximum power output, open circuit potential and short circuit current of the MFC were 1.796 W m−3, 0.559 V and 9.3375 A m−3, respectively. The energy required for electrochemical reoxidation ranged from 40% to 55% of the energy produced by the MFC. Results indicated that the Ag2O/Ag electrode could be used as a cathodic electron acceptor in MFCs with excellent stability.

An Overview of Electron Acceptors in Microbial Fuel Cells.

Microbial fuel cells (MFC) have recently received increasing attention due to their promising potential in sustainable wastewater treatment and contaminant removal. In general, contaminants can be removed either as an electron donor via microbial catalyzed oxidization at the anode or removed at the cathode as electron acceptors through reduction. Some contaminants can also function as electron mediators at the anode or cathode. While previous studies have done a thorough assessment of electron donors, cathodic electron acceptors and mediators have not been as well described. Oxygen is widely used as an electron acceptor due to its high oxidation potential and ready availability. Recent studies, however, have begun to assess the use of different electron acceptors because of the (1) diversity of redox potential, (2) needs of alternative and more efficient cathode reaction, and (3) expanding of MFC based technologies in different areas. The aim of this review was to evaluate the performance and applicability of various electron acceptors and mediators used in MFCs. This review also evaluated the corresponding performance, advantages and disadvantages, and future potential applications of select electron acceptors (e.g., nitrate, iron, copper, perchlorate) and mediators.

Power recovery coupled with sulfide and nitrate removal in separate chambers using a microbial fuel cell

A novel denitrifying sulfide removal microbial fuel cell (MFC), using sulfide and nitrate separately as the anodic electron donor and the cathodic electron acceptor, was explored to recover power coupled with pollutants removal. Power recovery coupled with sulfide and nitrate removal in this MFC was achieved under different buffers, hydraulic retention times (HRTs) and temperatures. Bicarbonate was deemed as a suitable alternative buffer to phosphate in this MFC, obtaining comparable power recovery and pollutant removal loadings but without potential secondary pollution. Shortening HRT from 5.54h to 2.27h or increasing temperature from 20°C to 30°C favored both power recovery and pollutants removal. The suitable HRT and temperature for this MFC were found to be 2.77h and 30°C, achieving a power density of 2.80±0.05W/m3 NC, a sulfide removal loading of 1.07±0.03kg S/(m3NCd), and a nitrate removal loading of 14.4±0.3gN/(m3NCd). Shortening HRT and lowering temperature would be beneficial to suppress sulfate formation, but more than 71.9% of sulfide was oxidized to sulfate in current study.

Petroleum refinery wastewater treatment in two-chamber microbial fuel cells (MFCS)

Petroleum refinery wastewaters (PRW) contain water-soluble hydrocarbons which can not be separated by physical methods. In recent years, there have been enormous approaches to treat PRW. The most outstanding methods involve biological, photocatalytic, electro photo-Fenton and etc. Using microbial fuel cell is a new method to treat PRW. In the present paper, treatment of petroleum wastewater of Isfahan refinery (COD= 213.9 mg/l, PH=7.1) was investigated in twochamber microbial fuel cell having 350 mL anode and cathode capacity. Anaerobic activated sludge prepared from Isfahan refinery treatment reactors was used as inoculum. Maximum power production was 0.03 W/m2 at 33 using oxygen as cathodic electron acceptor. Also COD removal efficiency was 49.27% during 44 hr. To enhance power production of the MFC, potassium permanganate was used as cathodic electron acceptor. At temperature of 33 and 0.2 g/l permanganate concentration, the maximum power density was 0.95 W/m2 and COD removal efficiency was 78% during 44hr. Then effect of temperature and external resistance on treatment of PRW was investigated. In fact the motivation of this paper is investigation of COD removal from PRW in two-chamber MFC.

Electricity Production in Microbial Fuel Cell Subjected to Different Operational Modes

The effects of inoculum species, substrate concentration, temperature, and cathodic electron acceptors on electricity production of microbial fuel cells (MFCs) were investigated in terms of start-up time and power output. When inoculated with aeration tank sludge, this MFC outperformed the cell that was inoculated with anaerobic sludge in terms of start-up time and power output. After running for a certain time period, the dominant populations of the two MFCs varied significantly. Within the tested range of substrate concentration (200–1800 mg L−1), the voltage output increased and the time span of the electricity generation lengthened with increasing substrate concentration. As the temperature declined from 35 to 10 °C, the maximum power density reduced from 2.229 to 1.620 W m−3, and anodic polarization resistance correspondingly dropped from 118 to 98 Ω. The voltage output of MFC–Cu2+ was 0.447 V, which is slightly lower than that achieved with MFC–[Fe(CN)6]3− (0.492 V), thereby indicating that MFCs could be used to treat wastewater containing Cu2+ pollutant in the cathode chamber with removal of organics in anode chamber and simultaneous electricity generation.