Use of Cyclic Voltammetry to Describe the Electrochemical Behavior of a Dual-Chamber Microbial Fuel Cell

Abstract

Cyclic voltammetry (CV) was used in this work to describe the electrochemical behavior of a dual-chamber microbial fuel cell (MFC). The system performance was evaluated under vacuum and non-pressurized conditions, different reaction times, two sweep potentials, 25 and 50 mVs−1 and under different analyte solutions, such as distilled water and domestic wastewater. CV experiments were conducted by using a potentiostat with three different configurations to collect the measurements. A dual-chamber MFC system was equipped with a DupontTM Nafion® 117 proton exchange membrane (PEM), graphite electrodes (8.0 cm × 2.5 cm × 0.2 cm) and an external electric circuit with a 100-Ω resistor. An electrolyte (0.1 M HCl, pH ≈ 1.8) was used in the cathode chamber. It was found that the proton exchange membrane plays a major role on the electrochemical behavior of the MFC when CV measurements allow observing the conductivity performance in the MFC in the absence of a reference electrode; under this potentiostat setting, less current density values are obtained on the scanned window potentials. Therefore, potentiostat setting is essential to obtain information in complex electrochemical processes present in biological systems, such as it is the case in the MFCs. Results of the study showed that wastewater constituents and the biomass suspended or attached (biofilm) over the electrode limited the electron charge transfer through the interface electrode-biofilm-liquor. This limitation can be overcome by: (i) Enhancing the conductivity of the liquor, which is a reduction of the ohmic drop, (ii) reducing the activation losses by a better catalysis, and (iii) by limiting the diffusional gradients in the bulk liquor, for instance, by forced convection. The use of the electrolyte (0.1 M HCl, pH ≈ 1.8) and its diffusion from the cathode to the anode chamber reduces the resistance to the flow of ions through the PEM and the flow of electrons through the anodic and cathodic electrolytes. Also reduces the activation losses during the electron transfer from the substrate to the electrode surface due to the electrode catalysis improvement. On the other hand, vacuum also demonstrated that it enhances the electrochemical performance of the dual-chamber MFC due to the fact that higher current densities in the system are favored.

Valorization of lignin to obtain platform chemicals via bio‐electrochemical systems: batch and fed‐batch mode analysis

“…CV is an electrochemical method used to investigate a system's electrochemical behavior. CV could also contain related details about the highest potential on the scan rate, allowing researchers to investigate the appropriate current and voltage of the redox species engaged in the system 18 . When the peak occurrence of H 2 O 2 output and electric production occurred, CV readings were recorded.…”

“…CV could also contain related details about the highest potential on the scan rate, allowing researchers to investigate the appropriate current and voltage of the redox species engaged in the system. 18 When the peak occurrence of H 2 O 2 output and electric production occurred, CV readings were recorded. The CV investigations characterized the cycles by scanning the potential in the cathodic direction to measure the electrochemical performance and voltammogram with redox peaks.…”

Advances in anode configurations for a microbial fuel cell via a computational fluid dynamics electrochemistry and its experimental validation

“…The conductivity of current in the anodic anolytes (wastewater + electro‐active bacteria) was restricted by the surface area of the anode electrodes, which was associated with the wastewater composition and growth of biofilm. This limit can be enhanced by increasing the surface area of the electrode through the design of electrodes, lowering activation losses and analyzing the anolyte concentration to maximize the reaction rate 64,66 . The concentration profile over the surface of the anodic electrode and bioelectric analysis are two of the most important criteria for increasing the efficiency of the MFCs.…”

Examining the Electrochemical Nature of an Ionogel Based on the Ionic Liquid [P66614][TFSI] and TiO2: Synthesis, Characterization, and Quantum Chemical Calculations

“…At higher scan rates with a shorter time, the charged species fail to undergo complete adsorption at the electrode/electrolyte interface, which results in poorer rate performance of the electrode. ,, Although the existence of functional groups at the surface of the electrode and/or the presence of dissolved impurities may impart some pseudo-capacitance, the linearity of the measured current suggests that the system is predominantly nonfaradaic within this potential range . A relatively narrow current density obtained over the given potential window could be due to the absence of an ideally polarizable reference electrode …”