• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.412-419
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• 2023

Anion exchange membrane electrolysis is considered a promising next-generation hydrogen production technology that can produce low-cost, clean hydrogen. However, anion exchange membrane electrolysis technology is in its early stages of development and requires intensive research on electrodes, which are a key component of the catalyst-system interface. In this study, we optimized the pressure conditions of the hot-pressing process to manufacture cobalt oxide electrodes for the development of a high uniformity and high adhesion electrode production process for the oxygen evolution reaction. As the pressure increased, the reduction of pores within the electrode and increased densification of catalytic particles led to the formation of a uniform electrode surface. The cobalt oxide electrode optimized for pressure conditions exhibited improved catalytic activity and durability. The optimized electrode was used as the anode in an AEMWE single cell, exhibiting a current density of 1.53 A cm^-2 at a cell voltage of 1.85 V. In a durability test conducted for 100 h at a constant current density of 500 mA cm^-2, it demonstrated excellent durability with a low degradation rate of 15.9 mV kh^-1, maintaining 99% of its initial performance.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.338-344
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• 2017

Polyoxometal molybdophosphoric acid (MoPA) bonded polyether ether ketone (PEEK) composite membrane for water electrolysis has been investigated. The composited membrane, covalently cross linked (CL) sulfonated polyether ether ketone (SPEEK) with a bonded MoPA, was prepared in sulfonation of PEEK, cross linkage reaction with 1,4-diiodobutane, and addition with MoPA. PEEK was covalently cross-linked with 1,4-diiodobutane to improve mechanical strength and was added with MoPA to increase proton conductivity. MoPA should be fixed to back bone of SPEEK to prevent bleeding out. Therefore, the carbonyl group of SPEEK was reduced with NaBH4 and 3-isocyanatepropyltriethoxysilane (ICPTES) was added. The MoPA bonded composite was produced in the reaction of MoPA with 3-mercaptopropyltrimethoxvsilane (MPTMS). In conclusion, MoPA bonded CL-SPEEK composite membrane featured 0.129 S/cm of proton conductivity at $80^{\circ}C$, and 2,156 hours of chemical stability in Fenton test. These properties are better than those of membranes of other SPEEK system.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.551-560
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• 2004

The feasibility and efficiency of the hydrogen peroxide produced by an electrolysis cell reactor was investigated, From regulating voltages for the given reaction time, the concentration of the hydrogen peroxide was gradually increased with increasing voltages. Optimal voltage range was found to be 10～15 V. The concentration of hydrogen peroxide was much higher with oxygen gas than without oxygen gas in the cathodic chamber. But there was a little difference in the generating rate of hydrogen peroxide regardless of the presence of nitrogen gas. Under given conditions, the maximum value of ICE(Instantaneous Current Efficiency) was about 38%, and then current density was 74 $mA/\textrm{cm}^2.$ The specific energy consumption was $0.694[kWh/kg-H_2O_2].$ Since Esp (Specific Energy Consumption)was very little value, It did not demand high energy in this system. Using the hydrogen peroxide gained in the experiment, Fenton's reaction was conducted and the removal of nitrobenzene, 3-chlorophenol and dye wastewater was studied. This results were very similar to the Fenton's reaction by using commercial hydrogen peroxide.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1229-1237
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• 2003

The production of hydrogen fuel depends basically on the water electrolysis. The ultrasonic effects the decrease of the overpotential in a water electrolysis. A study on the overpotential which activates the hydrogen production is the core to elevate the hydrogen production efficiency on the principle. A pressure sensor system by a new idea is developed and applied. Solutions are 4 kinds of KOH concentration such as 0%, 10%, 20%, and 30%. Two frequency bands of the ultrasonic transducer are 28kHz and 2MHz. The directions of ultrasonic forcing are the vertical direction and the horizontal direction. The temperatures are two states, i.e., no constant and constant. Experiments are carried out sequentially in order in three cases of no ultrasonic forcing, ultrasonic forcing, and ultrasonic discontinution. In results, it is clarified that the ultrasonic effects the decrease of overpotential to elevate the efficiency of hydrogen production.

• Environmental Engineering Research
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• v.25 no.3
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• pp.324-334
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• 2020

Tannery wastewater is known to contain high concentrations of organic compounds, pathogens, and other toxic inorganic elements such as heavy metals, nitrogen, sulfur, etc. Biological methods such as aerobic and anaerobic processes are unsuitable for tannery wastewater treatment due to its high salinity, and electrochemical oxidation offers a promising method to solve this problem. In this study, raw tannery wastewater treatment using DSA® Ti/RuO₂, Ti/IrO₂ and Ti/BDD electrodes with continuous flow systems was examined. Effects of current densities and electrolysis times were investigated, to evaluate the process performance and energy consumption. The results showed that a Ti/BDD electrode is able to reach higher treatment efficiency than Ti/IrO₂, and Ti/RuO₂ electrodes across all parameters, excluding Total Nitrogen. The main mechanism of tannery wastewater oxidation at a Ti/BDD electrode is based on direct oxidation on the electrode surface combined with the generation of oxidants such as °OH and Cl₂, while at DSA® Ti/RuO₂ and Ti/IrO₂ electrodes, the oxidation mechanisms are based on the generation of chlorine. After treatment, the effluents can be discharged to the environment after 6-12 h of electrolysis. Electrooxidation thus offers a promising method for removing the nutrients and non-biodegradable organic compounds in tannery wastewater.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.1-8
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• 2007

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.737-745
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• 1996

In recent years, with the increase in the consumption of natural resources and energy, global environmental problems have appeared. This is a very serious environmental load on worldwide food production. For this reason, innovative techniques for production of low entropy by using effectively the energy for the ecosystemic agriculture have been expected. In this study, granular ceramics of 2 to 3mm in diameter having electrical charges at the surface were produced, using the natural raw materials of silicate minerals haing excellent moldabilities and sintering properties . Production of water having functions was attempted by effective use of the electrochemical energy of the ceramics with an efficient water treatment apparatus in which the ceramics were fluidized in water, differently from conventional systems. In the experimental results, the EC of water treated with the ceramics was not changed, but the ORP and also the pH and the DO were changed. The speed of oxidation -re uction reaction was high, and the ceramics -treated water enhanced the vigor of seeds. It can be expected that this treatment system, by which the ORP of water can be moderately controlled, is advantageous in controlling the growth of plants.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.5
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• pp.395-406
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• 2015

The Ballast Water Treatment System was developed to prevent the unintended transport of unwanted organisms from one region to another as demanded by the IMO (International Maritime Organization). Although various types of BWTS in the world have been developed until now and applied to various ships, there has been no systematic basis for its selection and installation. Currently, the system selection and installation are as per ship owner’s suggestion or by easy installation point of view by the shipyard. In order to organize, systemize and solve problems related to the selection and installation of BWTS, a definitive study has been performed to come up with the best alternative to derive value and criteria which were to be met for vessels which are to be equipped with BWTS. Multiple criteria were compared alongside each other during the course of this study. Accordingly an AHP (Analytic Hierarchy Process) analysis method for A, B and C companies were done for container ships with size 10,000 TEU and above. Equipment type for “A” company is “Filter, UV & TiO2” combined type. For “B” company it is “Filter & UV” combined type. Finally for “C” company it is “Electrolysis” type. Henceforth, the results of this study aims to come up with the optimum way to select the best and the most suitable BWTS for a certain vessel.

• Resources Recycling
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• v.21 no.6
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• pp.45-50
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• 2012

The room-temperature electrodeposition of metallic lithium was investigated from ionic liquid, 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) with lithium bis (trifluoromethanesulfonyl)imide (LiTFSI) as a lithium source. Cyclic voltammograms on gold working electrode showed the possibility of the electrodeposition of metallic lithium, and the reduction current on a gold electrode was higher than the value on platinum and copper. The metallic lithium could be electrodeposited on the gold electrode under potentiostatic condition at -2.4 V (vs. Pt-QRE) and was confirmed by analytical techniques including XRD and SEM-EDS. The dendrite-typed electrodeposits were composed of a metallic lithium and a alloy with gold substrate. And any impurity could be detected except for trace oxygen introduced during handling for the analyses.

• Food Science and Preservation
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• v.16 no.3
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• pp.342-347
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• 2009

We sought to improve the methods for washing fresh raw ginseng. The quality of ginseng surface-washed by different methods was evaluated during storage at 10C and $20^{\circ}C$. The raw ginseng surface-washing method was a full-cone spray-type procedure using water and air. The water for decontamination had an electrolysis value of 80 ppm, also known as electrolysis water $2^{\circ}C$ water and water containing 5 ppm chlorine dioxide, were also used for decontamination. The Hunter color (${\Delta}E$) of ginseng washed with water withan electrolysis value of 80 ppm, or water with 5 ppm chlorine dioxide, was greater than that seen after other washing methods were used. The weight loss after washing with 5 ppm chlorine dioxide water was similar to that seen after washing with $2^{\circ}C$ water or 80 ppm electrolysis water. Reductions in total microorganism levels, and counts of yeasts and molds, assayed 10 days after washing with 5 ppm chlorine dioxide water were greater than seen after use of other sterilization methods. Quality maintenance on storage, at both 10C and 20C, after washing with 80 ppm electrolysis water, was better than that noted after other sterilization methods. The moisture content of washed ginseng was similar under all storage conditions tested.