High power microbial fuel cell operating at low temperature using cow dung waste

Moving towards green technology, alternatives to current detrimental, unsustainable, and expensive energy applications for eco-friendly energy are attracting great attention. Resource recycling and the convenient treatment of animal waste to diminish its nature impact are recently momentous subjects. Microbial fuel cells used cow waste have remarkable potential in electrical energy generation for clean, renewable and sustainable operation. In this study, double-chambered MFC was manufactured using cow manure as raw material at the anode chamber, graphite as the anode and cathode electrodes, fountain water in the cathode chamber, and proton exchange membrane. Because bacteria a catalytic reaction for the latent chemical energy of the cow manure was effectuated as a result of this, MFCs produced electricity. Electricity production performance of this MFC at low temperature (0–10 °C) conditions was examined. This MFC produced a maximum of 204.9 ± 0.1 mV open circuit voltage and 57.387 mW/m2 power density under low temperature conditions. In particular, the sustainability and applicability of MFCs have been increased thanks to this operation done at low temperatures (0–10 °C).

The Utilisation of Solid Fuels Derived from Waste Pistachio Shells in Direct Carbon Solid Oxide Fuel Cells

The comprehensive results regarding the physicochemical properties of carbonaceous materials that are obtained from pistachio shells support their usage as solid fuels to supply direct carbon solid oxide fuel cells (DC-SOFCs). The influence of preparation conditions on variations in the chemical composition, morphology of the biochar powders, and degree of graphitization of carbonaceous materials were investigated. Based on structural investigations (X-ray diffraction analysis and Raman spectroscopy), it was observed that disordered carbon particles developed during the application of thermal treatments. The use of X-ray fluorescence enabled a comparative analysis of the chemical composition of the inorganic matter in biocarbon-based samples. Additionally, the gasification of carbonaceous-based samples vs. time at a temperature of 850 °C was investigated in a H2O or CO2 gas atmosphere. The analysis demonstrated the conversion rate of biochar obtained from pistachio shells to H2, CH4 and CO during steam gasification. The electrochemical investigations of the DC-SOFCs that were supplied with biochars obtained from pistachio shells were characterized by satisfactory values for the current and power densities at a temperature range of 700–850 °C. However, a higher power output of the DC-SOFCs was observed when CO2 was introduced to the anode chamber. Therefore, the impact of the Boudouard reaction on the performance of DC-SOFCs was confirmed. The chars that were prepared from pistachio shells were adequate for solid fuels for utilization in DC–SOFCs.

The operation characteristics of air cathode Microbial Desalination Cell to treat oil refinery wastewater

This system [microbial desalination cell (MDC)] is considered an excellent sustainable process to treat wastewater by biological anaerobic oxidation of the organic material by electroactive bacteria, desalinate saltwater, and electrical power generation. In the present work, MDC was used for treating oil refinery wastewater in the anode chamber by anaerobic bacteria. Simultaneously, an air pump was used to provide the oxygen to the cathode chamber as an electron acceptor to generate bioelectricity power. The power density generated by this air cathode MDC with 1KΩ external resistance at the 1st experiment was 71.11 μW/m2. It increased to a peak value of 570.86 μW/m2 at the last experiment. The maximum chemical oxygen demand (COD) removal percent of oily wastewater was 96%. The higher salinity removal rate 150.39 ppm/h with a first salt concentration in a desalinating chamber of 35000 ppm.

Simultaneous CO2 Treatment and Blue Energy Generation from Wasted Industrial Streams

In the last decade, there has been an increased global need for finding bright solutions to tackle industrial wastes and emissions release. Herein, this work explores the utilization of a compact Reverse Electrodialysis (RED) system that transforms the chemical potential energy of mixing an ammonia based purified industrial wastewater stream (low concentration stream - LC), with an effluent high salinity RO brine stream (High concentration-HC) into viable electrical energy. The LC and HC streams are directed from ammonia production plants and seawater reverse osmosis desalination plants, respectively. The acquired electrical energy from this RED process is simultaneously used to power an Electrochemical (EC) system. The electrochemical system utilizes two critical waste streams produced from ammonia production plants. One being a wastewater stream that is purified in the anode chamber of the cell via the use of active chlorine species, and the other being the huge amount of emitted CO2 that is directed into the cathode chamber and there converted to value added chemicals. The purified wastewater stream coming out of the EC system is used as the aforementioned LC stream in the RED process, hence, forming an integrated RED-EC system that manages industrial waste streams, minimizes liquid discharge & CO2 emissions, and employs a sustainable internal energy production process. In this study, the RED system is first optimized to attain the maximum power density through exploring the influence of concentrate and dilute stream concentrations, compositions and flowrates. In addition, to the number of membrane pairs needed to produce desired voltages. The RED cell gave a maximum power density of 3.25 W.m-2 with 20 membrane pairs and a salinity gradient of 0.98M between a concentrated brine stream and a mixed NaCl/(NH4)2SO4 stream. Furthermore, around 15 cell pairs were needed to provide -1.5 V of energy to drive CO2 conversion to formate.

Generation of Bioelectricity from Organic Fruit Waste

This research proposes an alternative for companies and farmers through the production of electricity using microbial fuel cells (MFCs) using waste from export products. Nine MFCs were manufactured with zinc and copper electrodes; and as substrates, pineapple, potato and tomato pulp wastes were used in the anode chamber, and residual sludge in the cathode chamber. It was observed that the MFCs with pineapple substrate generated higher values of the electrical parameters, resulting in voltage and current values of 0.3484 ± 0.003 V and 27.88 ± 0.23 mA, respectively. It was also observed that the maximum power density was 0.967 ± 0.059 W/cm2 at a current density of 0.04777 A/cm2 for the same substrate. Acid pH values were observed in the three samples, while the conductivity reached its maximum value on day 23 (69.47 ± 0.91 mS/cm) which declined until the last day of monitoring; the turbidity values increased abruptly after day 22 until the last day where a value of 200.3 ± 2.52 UNT was observed for the pineapple substrate. The scanning electron microscopy for the pineapple substrate MFC electrodes shows the formation of a porous biofilm on the zinc and copper electrodes. These results show that a new form of electricity production has been achieved by generating high voltage and current values, using low-cost materials.

Antibiotic Resistance Gene Was Increased via Horizontal Transfer in Single and Two-Chamber Microbial Electrolysis Cells

Microbial electrolysis cells (MECs), have been applied for antibiotic degradation, but simultaneously induced antibiotic resistance genes (ARGs), thus representing a risk to disseminate antibiotic resistance. However, there were few studies on the potential and risk of ARGs transmission in the MECs. In this work, conjugative transfer of ARGs was assessed under three tested conditions (voltages, cell concentration, and donor/recipient ratio) in both single and two-chamber MECs. The results indicated that voltages (> 0.9 V) facilitate the frequency in single-chamber the MECs and two-chamber the MECs (in anode chamber). The donor cell number (donor/recipient ratio was 2:1) showed more favor on the transfer frequency. Furthermore, voltages ranged from 0.9 V to 2.5 V increased ROS production and cell membrane permeability in MECs. These findings offer new insights into the roles of ARGs transfer under different applied voltages in the MECs, which should not be ignored for horizontal transfer of antibiotic resistance.

Degradation of Diclofenac in Urine by Electro-Permanganate Process Driven by Microbial Fuel Cells

A novel microbial fuel cell-assisted electro-permanganate process (MFC-PM) was proposed for enhanced diclofenac degradation compared to that of the permanganate oxidation process. By utilizing eco-friendly bio-electricity in situ, the MFC-PM process could activate the simultaneous anodic biological metabolism of urea and the cathodic electro-permanganate process. Density functional analysis and experimental evidence revealed the reactive manganese species (Mn(VII)aq, Mn(VI)aq, Mn(V)aq, and Mn(III)aq), generated via single electron transfer, contributed to diclofenac degradation in the cathodic chamber. The sites of diclofenac with a high Fukui index were preferable to be attacked by reactive manganese species, and diclofenac degradation was mainly accomplished through the ring hydroxylation, ring opening, and decarboxylation processes. Biological detection revealed clostridia were the primary electron donor in the anode chamber in an anaerobic environment. Furthermore, maximum output power density of 1.49 W m−3 and the optimal removal of 94.75% diclofenac were obtained within 20 min under the conditions of pH = 3.0, [DCF]0 = 60 µM, and [PM]0 = 30 µM. Diclofenac removal efficiency increased with external resistance, higher PM dosage, and lower catholyte pH. In addition, the MFC-PM process displayed excellent applicability in urine and other background substances. The MFC-PM process provided an efficient and energy-free bio-electricity catalytic permanganate oxidation technology for enhancing diclofenac degradation.

Bioenergy Potential of Albumin, Acetic Acid, Sucrose, and Blood in Microbial Fuel Cells Treating Synthetic Wastewater

Microbial fuel cells (MFCs) are a recent biotechnology that can simultaneously produce electricity and treat wastewater. As the nature of industrial wastewater is very complex, and it may contain a variety of substrates—such as carbohydrates, proteins, lipids, etc.—previous investigations dealt with treatment of individual pollutants in MFCs; the potential of acetic acid, sucrose, albumin, blood, and their mixture has rarely been reported. Hence, the current investigation explored the contribution of each substrate, both separately and in mixture. The voltage generation potential, current, and power density of five different substrates—namely, acetic acid, sucrose, albumin, blood, and a mixture of all of the substrates—was tested in a dual-chambered, anaerobic MFC operated at 35 °C. The reaction time of the anaerobic batch mode MFC was 24 h, and each substrate was treated for 7 runs under the same conditions. The dual-chambered MFC consisted of anode and cathode chambers; the anode chamber contained the biocatalyst (sludge), while the cathode chamber contained the oxidizing material (KMnO4). The maximum voltage of 769 mV was generated by acetic acid, while its corresponding values of current and power density were 7.69 mA and 347.85 mW, respectively. Similarly, being a simple and readily oxidizable substrate, acetic acid exhibited the highest COD removal efficiency (85%) and highest Coulombic efficiency (72%) per run. The anode accepted the highest number of electrons (0.078 mmol/L) when acetic acid was used as a substrate. The voltage, current, and power density generated were found to be directly proportional to COD concentration. The least voltage (61 mV), current (0.61 mA), and power density (2.18 mW) were observed when blood was treated in the MFC. Further research should be focused on testing the interaction of two or more substrates simultaneously in the MFC.

Enhancing the anode performance of microbial fuel cells in the treatment of oil-based drill sludge by adjusting the stirring rate and supplementing oil-based drill cuttings

This was the first attempt to investigate the bioelectricity output based on solid-liquid cooperation in the microbial fuel cell (MFC) treatment of oil-based drill sludge by adjusting the stirring rate (SR) and supplementing oil-based drill cuttings (OBDCs). According to the results, the maximum power density output reached 671 mW/m2 (5.4 kW h/m2) when the stirring rate was 100 r/min and the OBDCs concentration was 2 g/L in the anode chamber, which was more than 2.4 times as high as that of the control group and significantly higher than those of other MFCs. Extremely high removal efficiencies of chemical oxygen demand (COD), ammonia and total inorganic nitrogen (TIN) were realized in optimization, with values of 52.3 ± 1.9% (the removal quality was 12081 ± 432 mg/L), 74.5 ± 0.2% and 58.9 ± 0.2%, respectively. Electrochemical analyses and high-throughput sequencing revealed that the cooperation of stir with OBDCs could activate microbial activity while reducing the overpotential loss in anode systems and thus responsible for the enrichment of electrogenic bacteria with extracellular electron transfer functions (such as Proteobacteria, Bacteroidetes and Actinobacteria) and denitrifying bacteria (such as Bacilli and Anaerolineae and Rhodopseudomonas). Moreover, substrate characterization (via Fourier-transform infrared spectrometry (FT-IR) and X-ray diffraction (XRD)) showed that organic matter might converted into small molecules without intermediates. This investigation offers a new strategy for the treatment /application of solid and liquid produced from oil and gas fields by bioelectrochemical technology.

Simultaneous Removal of Trivalent Arsenic and Nitrate Using Microbial Fuel Cells

A rectangular double chamber with trivalent arsenic as the electron donor of the biological anode was constructed by microbial fuel cells (MFC), and the feasibility of the MFC simultaneous degradation of trivalent arsenic and nitrate was studied. Experimental results show that the co-matrix-coupled MFC reactor oxidizes trivalent arsenic in an anode chamber and degrades nitrate in the cathode chamber. The removal rate of trivalent arsenic is about 63.35%, and the degradation rate of nitrate is about 55.95% during the complete and stable operation period. MFC can continuously output electric energy, and the maximum output voltage is 388 mV. We compared and analyzed the main functional microflora of biofilm microorganisms in an anode chamber. In the long-term arsenic-polluted environment, the activity of Acinetobacter, Pseudomonas bacteria with arsenic resistance, was improved. It is inferred that a fraction of trivalent arsenic was oxidized to pentavalent arsenic by electrode-attached microorganisms. While remaining trivalent, arsenic was taken up by the suspended bacterial biomass and converted into stable arsenide. The results of this study have theoretical reference value for the expansion of the MFC application scope.