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Oxidation/Reduction in Aquatic Chemistry
Published in Stanley E. Manahan, Environmental Chemistry, 2022
The Nernst equation is used to account for the effect of different activities on electrode potential. Referring to Figure 3.2, if the Fe3+ concentration is increased relative to the Fe2+ concentration, it is readily visualized that the potential and the pE of the right electrode will become more positive, because the higher concentration of electron-deficient Fe3+ clustered around it tends to draw electrons from the electrode. Decreased Fe3+ or increased Fe2+ concentration has the opposite effect. Such concentration effects upon E and pE are expressed by the Nernst equation. As applied to the half-reaction Fe3++e-↔Fe2+,E0=+0.77V,pE0=13.2
Battery Energy Storage
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
The potential of an electrode is the potential difference between the electrode and the electrolyte that it is in contact with. The electrode potential is determined with respect to a reference electrode, since an absolute potential value cannot be obtained. Both chemical and electrical processes contribute to the electrode potential difference [6]. The environment at the vicinity of an electrode is changed due to chemical activities between the electrode and the electrolyte regardless of the electric potential difference at the solid-liquid phase boundary. The measure of the work done to bring a particle to its assumed potential is the chemical potential. Again, regardless of the changes in the chemical environment the transfer across the electric potential is accomplished by electric work done in its original sense. Although one cannot separate these two components for single species experimentally, the differences in the scales of the two environments make it possible to separate them mathematically [7,8]. The resultant potential for these two kinds of energy change is the electrochemical potential or simply the electric potential.
Electrophysiology
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
In the biological signal acquisition, non-polarized electrodes are preferred for low-frequency measurements, whereas polarized electrodes are used for transient electrical stimulation at higher frequency range. Depending on the size and class of the electrodes, they are broadly classified into five types, namely, microelectrodes, needle electrodes, surface electrodes, fine wire electrodes and electrode arrays (Macy, 2015).
Plasma synthesis of ammonia by asymmetric electrode arrangement
Published in Materials and Manufacturing Processes, 2023
F. Baharlounezhad, M.A. Mohammadi, M.S. Zakerhamidi
Electrolysis is the process of passing an electric current through the material to cause a chemical change. This process takes place in an electrolytic cell, a reactor consisting of cathode and anode electrodes immersed in a solution containing positive and negative charged ions. An electrolytic cell, also known as an electrolysis reactor, converts electrical energy into chemical energy. Metal conductors are used as electrodes in electrolysis reactors. Electrodes are responsible for the transmission of electrons in certain circumstances and are also engaged in electrolysis processes in others. The cathode is the electrode that sends electrons to the anode across the electrolyte environment, and the anode is the electrode that receives electrons from the cathode. Electrolysis is widely used in metallurgical engineering [42,43] like electrowinning,[44,45] electrorefining,[46–48] and electroplating.[49,50] The electrodes of an electrochemical system with asymmetric electrode configurations might differ in form, size, material, and design from one another.
Producing electricity at estuaries from salinity gradient: exergy analysis
Published in International Journal of River Basin Management, 2022
S. Haddout, K. L. Priya, M. Rhazi, A. Jamali, M. Aghfir, A. M. Hoguane, I. Ljubenkov
This technique uses the dialysis concept and mostly named reversed Electro-Dialysis. The working principle of RED is shown in Figure 3. A mechanism for power generation is based on ion transport through the IEMs. When a concentrated solution (e.g. seawater) and a dilute solution (e.g. river water) are supplied to the system where cation exchange membranes (CEMs) and anion exchange membranes (AEMs) are alternately arranged, the ions spontaneously migrate owing to differences in chemical potential through the IEMs. Here, cations move through the CEMs and anions move through the AEMs. An electromotive force (EMF) is produced to preserve electrical neutrality in the system, and the ionic current is converted into electric current by the redox reaction on electrodes located at both ends (Kim et al., 2019). Electrical energy can be obtained from the movement of electrons through an external circuit in an electrical load. The typical RED system is composed of pumps, gaskets, spacers, electrodes, and IEMs. The IEM is a key component in RED because it selectively permeates cations (CEM) or anions (AEM) (Kim et al., 2019). Pumps are used to supply diluted and concentrated solutions and circulate the electrode rinse solution (redox couple) that reduces activation loss. Gaskets are employed for preventing leakage and spacers are located in the gaskets. Electrodes provide for electron exchange at the surface and transportation through an external circuit.
ELF-MF occupational exposure in die-casting and electroplating workers in Korea
Published in International Journal of Occupational Safety and Ergonomics, 2020
Rajitha Kawshalya Mailan Arachchige Don, Joon-Sig Jung, Yun-Jin Lee, Seung-Cheol Hong
Electroplating uses electric current to reduce dissolved metal cations to form a thin coherent metal coating on an electrode. The electroplating plant selected in this study processes vehicle assembly parts, such as car door handles, buffers, rims and hoods. At the die-casting plant, a metal casting process is used that drives liquid metal under high pressure into a mold cavity. Die castings are mostly made from non-ferrous metals such as zinc, copper, aluminum, lead or magnesium. The die-casting plant in this study was a hot chamber plant.