Corrosion Rates Of Electrodes Research Articles

Bioelectricity Production from Microbial Fuel Cell (MFC) Using Lysinibacillus xylanilyticus Strain nbpp1 as a Biocatalyst.

Microbial fuel cells (MFCs) function by using microorganisms to decompose the substrate at the anode, producing electrons and protons. These charges are then transported to the cathode, where electricity is generated. Previous studies have shown their promising probabilities for practical applications. MFCs are praised for their ability to address energy shortages and environmental pollution simultaneously. They have the potential to generate electricity directly from organic substances, reducing energy losses that occur during intermediate conversion steps. The main challenge lies in transitioning these technologies from the laboratory setting to practical systems that can be implemented on a large scale for bioenergy production along with various engineering hurdles. This study focused on investigating the power production potential of a soil-isolated bacterial strain taxonomically classified as Lysinibacillus xylanilyticus nbpp1, which is a relatively new addition to the extensive range of biocatalysts known for their ability to generate electricity. The study analyzed the electrochemical performance of an H-type MFC setup. LB broth was used as the substrate, while aluminum and graphite served as electrode materials. Other parameters, such as Coulombic efficiency, internal resistance, and electrode corrosion rate, were also measured. The MFC produced a high open circuit voltage of 1127mV and achieved a maximum power density of 6.71 mW/cm2 at a current density of 11.14mA/cm2. The MFC setup successfully powered LED lamps when connected in a joint circuit, showcasing its potential for practical applications. These findings suggest the promising high electrochemical performance of the MFC system in terms of electricity generation using the specified conditions.

The influence of Ohmic‐vacuum heating on phenol, ascorbic acid and engineering factors of kiwifruit juice concentration process

SummaryThe antioxidant, phenol, ascorbic acid, electrode corrosion and engineering factors of concentration process of kiwifruit juice by ohmic heating‐vacuum conditions (OHVC) were evaluated and compared with ohmic heating under atmospheric conditions (OHAC). Results showed that the total phenol content was decreased with an increasing voltage gradient for both heating modes. The OHVC can better save the antioxidant capacity and ascorbic acid of concentrated samples than the OHAC. The processing time of OHVC was significantly higher than the OHAC at the same voltage gradient (P < 0.05). The electrode corrosion rate at the vacuum mode was 7‐ to 40‐fold higher than the atmospheric mode. The energy efficiency at OHAC was lower than the OHVC. The energy consumption was found in the range of 3.37 to 3.75 MJ kg−1 water for OHAC and 4.08 to 11.09 MJ kg−1 water for OHVC. The electrical conductivity under the vacuum mode was lower than the atmospheric mode.

Effect of Gradient of Soil Aeration on Corrosion Rate at Different Depths from Ground Surface

In recent years, the number of photovoltaic electric power systems has drastically increased in Japan. Currently, metal piles are used in the foundations of these systems. However, a section of the metal foundation piles near the ground surface corrodes faster than . This problem has not been widely investigated. In our study, exposure tests were carried out in soil at three test sites, and macrocell current densities were measured at different soil depths based on the gradient of soil aeration. Soil samples from these sites were collected at every 50 mm of depth below the ground surface. Thereafter, the soil samples were used as electrolytes for AC impedance analysis of the components. The exposure test indicated that there were environment in which severely corroded in soil near the ground surface, and this environment was poorly drained. However, the results of the macrocell current density measurement and the AC impedance analysis indicated that the electrode corrosion rate near the ground surface was NOT faster than, but similar to, those for the other sections in deeper soil. Accordingly, a corrosion test was conducted by simulating the test site environment. For the corrosion test, a columnar soil tank (ϕ 200 mm × H 300 mm) and 18 steel electrodes (3.2 mm × 30 mm), each placed at 2 mm distance, were used. The macrocell current was measured using this tank of Arakita soil (paddy soil) that contained 15 wt.% water. Arakita soil used in this experiment was dried at 160 °C, milled, and passed through a sifter with 1 mm mesh net. were short-circuited. The voltage at both ends of the shunts was measured every 30 s, and the corresponding current was calculated using Ohm’s law. The spontaneous potentials of the electrodes were measured every 1 h Thereafter, AC impedance analysis of soil samples used as electrolytes that were collected from this tank at depths of ~50 mm and 250 ~ 300 mm were conducted. The experimental results suggested that a macrocell was formed at a depth of ~10 mm. The corrosion rates of the electrodes were calculated using the macrocell current. The electrode set at a depth of 5 mm near the ground surface exhibited the maximum corrosion rate of 0.07 mm/year. The spontaneous potential of this electrode was lower than that of all other electrodes, except for two electrodes set at the depths of 40 and 45 mm. The electrode set at a depth of 5 mm was significantly corroded, which corresponded to the corrosion mass loss measured by the exposure test. AC impedance analysis. From the results, the significant corrosion at the ground surface can be considered to be due to macrocell corrosion caused by the gradient of soil aeration. However, it is not clear whether the spontaneous potentials of the electrodes at depths of 40 and 45 mm are lower and whether the anodic current flows through these electrodes. Figure 1

Galvanic corrosion of carbon steel under concentration cell formation in MgCl2 solution as an inorganic pollutant and the effect of flow velocity

Abstract The wastewater of petroleum refineries consists of various corrosive pollutants that are harmful not only for human and living organisms but also for the equipment and materials exposed to it. The galvanic corrosion of carbon steel in MgCl2 solution as a pollutant in petroleum refinery wastewater was studied under concentration cell formation. The influence of different operating parameters on the galvanic corrosion established by concentration cell was studied, and the concept of concentration cell corrosion was examined and discussed versus experimental results. The effects of some operating conditions on the galvanic behavior, such as the concentration of MgCl2 (0–2500 ppm) and solution flow velocity (150–1000 rpm), on corrosion rate, corrosion potentials, and corrosion current were investigated. New findings regarding the effect of corrosive substance concentration and the hydrodynamics on the corrosion rate of each electrode and the galvanic current were reported. It was found that the corrosion rate of carbon steel in both cell poles increases with increasing MgCl2 concentration in both free and galvanic corrosion. Increasing MgCl2 concentration also led to an increase in the galvanic currents and the corrosion rate of the two electrodes. The flow velocity in either cell terminal considerably influences the potentials, corrosion rates of both electrodes, and the galvanic current passing in the cell. A high flow velocity in the compartment with the more negative potential caused polarity reversal on some occasions.

Wettability Effect on the Corrosion Kinetics of Iron Anodes in Sulfuric Acid Solutions

The interdependence of electrode wetting and electrode corrosion rate was studied for the iron anode in aqueous sulfuric acid solutions. The effects of acid solution concentration and surface‐active agents on the corrosion rate and passive‐active transition current oscillation amplitude were measured. The results show that both are dependent on the electrode wetting. The electrode wettability is shown to change as a function of time which results in convective liquid displacement around the electrode and on variable corrosion rates.