Hydrogen production profiles using furans in microbial electrolysis cells

Extracellular polymeric substances in electroactive biofilms play a crucial role in improving the efficiency of microbial fuel and electrolysis cells

In microbial electrochemical cells (MECs), electroactive microbial biofilms can transmit electrons from organic molecules to anodes. To further understand the production of anodic biofilms, it is essential to investigate the composition and distribution of extracellular polymeric substance (EPS) in the MECs. In this study, the structure of EPS was examined in microbial electrolysis cells from mixed cultures forming biofilm using carbon fiber fabric anode. EPS was extracted from the anode biofilm of microbial electrolysis cells inoculated with mixed microbial culture. The anode biofilm yielded 0.4 mg of EPS, of which 51.2% was humic substance, 16.2% was protein, 12.6% was carbohydrates, and 20% consisted of undetermined substances. Using epifluorescence microscopy, the composition of bacterial cells and their location inside EPS were studied, and the distribution of microbial communities was compared based on current density results in the presence of various carbohydrates. On the electrode surface, bacteria and EPS gathered or overlapped in various locations can affect microbial electrochemical performance. Our findings showed that EPS formation in electroactive biofilms would be important for enhanced efficiency of electricity- or hydrogen-producing microbial electrolysis cells.

Hydrogen production using cocaine metabolite in microbial electrolysis cells

In this study, the effects of cocaine metabolite, benzoylecgonine, commonly found in wastewater on hydrogen production were investigated using microbial electrolysis cells. Benzoylecgonine dissolved in synthetic urine and human urine containing benzoylecgonine were inoculated to evaluate hydrogen production performance in microbial electrolysis cells. Microbial electrolysis cells were inoculated with synthetic urine and human urine containing the cocaine metabolite benzoylecgonine for hydrogen gas production performance. Gas production was observed and measured daily by gas chromatography. GC-MS was used to analyze the compounds found in human urine before and after operation in microbial electrolysis cells. The metabolite's pH values and optical density in microbial electrolysis cells were analyzed spectrophotometrically. Hydrogen gas was successfully produced in microbial electrolysis cells (~ 5.5 mL) at the end of the 24th day in the presence of benzoylecgonine in synthetic urine. Human urine containing benzoylecgonine also generated hydrogen in microbial electrolysis cells. In conclusion, microbial electrolysis cells can be used to remove cocaine metabolites from contaminated wastewater generating hydrogen gas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03805-7.

Hydrogen production in single-chamber microbial electrolysis cells using Ponceau S dye

In this study, Ponceau S dye, which is one of the hazardous dyes found in industrial wastewater, was examined for hydrogen production in single chamber-free membrane-free microbial electrolysis cells at different concentrations (10-40 mg L^-1). A gas content analysis (hydrogen, carbon dioxide, and methane) was measured daily using gas chromatography to determine the effects of the Ponceau S on hydrogen production levels. Hydrogen was successfully produced in the presence of Ponceau S dye, but the gas production levels were affected by the concentrations of Ponceau S. The maximum hydrogen production was measured as 18 mL at a concentration level of 20 mg L^-1. Decolorization ratios of Ponceau S were in the range of 85-100%. Hydrogen production rates increased in the presence of Ponceau S (20 mg L^-1); however, yield (%) of the production decreased when compared to the control group. The percentage of COD removal was 94.78% in the presence of 40 mg L^-1 of Ponceau S. In conclusion, hydrogen can be generated using wastewaters contaminated with azo dyes such as Ponceau S, and decolorization of the dye can be achieved, simultaneously.

Bioremediation of wastewater through a quorum sensing triggered MFC: A sustainable measure for waste to energy concept

A mission for fast advancement has constrained us to unpredictably tap various natural assets. The reckless utilisation of fossil fuels led unmanageable wastes which have greatly affected our health and environment. Endeavours to address these difficulties have conveyed to the frontal area certain creative natural solutions particularly the utilisation of microbial digestion systems. In the previous two decades, the microbial fuel cell (MFC) innovation has caught the consideration of the researchers. The MFCs is a kind of bio-electrochemical framework with novel highlights, for example, power production, wastewater treatment, and biosensor applications. Lately, dynamic patterns in MFC inquire about on its synthetic, electrochemical, and microbiological perspectives have brought about its observable applications. The MFCs have begun as a logical interest, and in numerous regards, these remaining parts to be the situation. This is especially a result of the multidimensional uses of this eco-accommodating innovation. The innovation relies upon the electroactive microorganisms, prominently known as exoelectrogens. In the first place, it is the main innovation that can create energy out of waste, without the contribution of outer/extra energy. Modification of electrodes with nanomaterials, for example, gold nanoparticles and iron oxide nanoparticles or pretreatment techniques, for example, sonication and autoclave disinfection have indicated promising outcomes in improving MFC execution for power generation and wastewater treatment. The MFC innovation has been likewise explored for the remediation of different heavy metals and hazardous components, and to recognize the poisonous components in wastewater. What's more, the MFCs can be adjusted into microbial electrolysis cells to produce hydrogen energy from different natural sources. This article gives a thorough and cutting-edge appraisal of the novel magnitudes of the MFC.