• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.600-606
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• 2007

Livestock wastewater containing concentrated organic matters and nutrients has been known as one of the major pollutants. It is difficult to apply the conventional activated sludge process to treat livestock wastewater because of high Non-biodegradable (NBD) matter and ammonia. The objectives of this study are to remove NBD matters including aromatic compounds and ammonia in livestock wastewater using Coagulation-Fenton oxidation-Zeolite (CFZ) processes and ascertain applicable feasibility in the field through pilot plant experiment. NBD matters and color remained in the treated water were removed over 92% by Fenton oxidation as the second treatment process. Ammonia was removed by over 99.5% in the zeolite ion exchange process as the last treatment method. From $UV_{254}$, $E_2/E_3$ ratio and GC/MS analyses of treated water at each process, the aromatic compound was converted to aliphatic and aromaticity was decreased. In pilot scale test, organics and ammonia removal efficiencies were not much different from the result of lab-scale test at various operation conditions. Furthermore, reaction time and dosage of Fenton reagent in pilot scale experiment reduced by 40 min and 50% rather than in lab-scale test. $BOD_5$, $COD_{Mn}$, SS, T-N and T-P of treated water in the pilot-scale experiment also met the effluent standards.

• Journal of the Korean institute of surface engineering
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• v.55 no.3
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• pp.180-186
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• 2022

The production of hydrogen via water electrolysis (i.e., green hydrogen) using renewable energy is key to the development of a sustainable society. However, most current electrocatalysts are based on expensive precious metals and require the use of highly purified water in the electrolyte. We demonstrated the preparation of a non-precious metal catalyst based on CuCo₂O₄ (CCO) via simple electrodeposition. Further, an optimization process for electrodeposition potential, solution concentration and electrodeposition method was develop for a catalyst-substrate integrated electrode, which indicated the highly electrocatalytic performance of the material in electrochemical tests and when applied to an anion exchange membrane water electrolyzer.

• Membrane Journal
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• v.13 no.3
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• pp.143-153
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• 2003

The effects of bipolar interface formed on the surface of cation-exchange membrane on water splitting phenomena were investigated. Results showed that the formation of immobilized bipolar interface resulted in significant water splitting during electrodialysis. In particular, the immobilized bipolar interface was easily created on the cation-exchange membrane surface in the electrodialytic systems where multivalent cations served as an electrolyte. Multivalent cations with low solubility product resulted in violent water splitting because they were easily precipitated on the membrane surface in hydroxide form. Therefore, the bipolar interface consisting of H- and OH-affinity groups were formed on the membrane-solution interface. Apparently, water splitting was largely activated with the help of strong electric fields generated between the metal hydroxide layer and fixed charge groups on the membrane surface. Likewise, the accumulation of large molecular counter ions on the membrane surface led to the formation of a fixed bipolar structure that could cause significant water splitting in the over-limiting current region. Therefore, the prevention of the immobilization of bipolar interface on the membrane surface is very essential in improving the process efficiency in a high-current operation.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.332-339
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• 2021

Recently, due to concerns about the depletion of fossil fuels and the emission of greenhouse gases, the importance of hydrogen energy technology, which is a clean energy source that does not emit greenhouse gases, is being emphasized. Water electrolysis technology is a green hydrogen technology that obtains hydrogen by electrolyzing water and is attracting attention as one of the ultimate clean future energy resources. In this study, the surface properties of the porous transport layer (PTL), one of the cell components of the proton exchange membrane water electrolysis (PEMWE), were controlled using a sandpaper to reduce overvoltage and increase performance and stability. The surfaces of PTL were sanded using sandpapers of 400, 180, and 100 grit, and then all samples were finally treated with the sandpaper of 1000 grit. The prepared PTL was analyzed for the degree of hydrophilicity by measuring the water contact angle, and the surface shape was observed through SEM analysis. In order to analyze the electrochemical characteristics, I-V performance curves and impedance measurements were conducted.

• Journal of Environmental Science International
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• v.9 no.3
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• pp.261-266
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• 2000

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k$_1$ was 0.07~0.17 $\ell$/mgㆍhr and maximum exchange quantity q$_{o}$ was 27.75~31.81 mg/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 mg/$\ell$ nitrate-contained wastewater of 10,000 gallons per day to 2 mg/$\ell$, total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.y.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.194-197
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• 2002

Ion exchange is a chemical reaction between the ions in solution phase and ions in solid phase and is widely used in softening, demineralization, removal and collection of specific ions, and ion migration in the ground water. The ion selectivity depends on the charge and the hydrated radius of ion. The objective of this study was to examine the applicability of anion selectivity obtained from the ion exchange equilibrium OH/sup -/ < F/sup -/ < HCO/sup -/ < Cl/sup -/ < Br/sup -/ ≤ NO₃/sup -/ < SO₄/sup 2-/ to the column ion exchange. The column ion exchange was facilitated in the lower charge of counter-ion in the background electrolyte.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.77-80
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• 2006

Chloromethylated polysulfone(CMPSf) and a number of mono- and diamine compounds were used to prepare anion-exchange membranes(AEMs) and an ionomer binder solution. The properties of the AEMs were investigated such as $OH^-$ conductivity, water content and dimension stability. Chloromethylation and amination of PSf were optimized in terms of the properties. Membrane-electrode assemblies were fabricated using anion-exchange membranes and the ionomer binder for solid alkaline fuel cells and direct borohydride fuel cells.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.3
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• pp.128-137
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• 2013

Due to the global warming and air pollution, interest in renewable energies has increased in recent years. In particular, the crisis of the depletion of fossil energy resources in the near future has accelerated the renewable energy technologies. Among the renewable energy resources, oceans covering almost three-fourths of earth's surface have an enormous amount of energy. For this reason, various approaches have been made to harness the tremendous energy potential. In order to achieve two purposes: to improve harbor water quality and to use wave energy, this study proposed a sea water exchange structure applying an Oscillating Water Column (OWC) wave generation system that utilizes the air flow velocity induced by the vertical motion of water column in the air chamber as a driving force of turbine. In particular, the airflow velocity in the air chamber was estimated from the time variations of water surface profile computed by using 3D-NIT model based on the 3-dimensional irregular numerical wave tank. The relationship of the frequency spectrums between the computed airflow velocities and the incident waves was analyzed. This study also discussed the characteristics of frequency spectrums in the air chamber according to the presence of the structure, wave deformations by the structure, and the power of the water and air flows were also investigated. It is found that the phase difference exists in the time series data of water level fluctuations and air flow in the air chamber and the air flow power is superior to the fluid flow power.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.861-867
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• 2006

In connection with redevelopment of Busan North Port, there has been lots of studies and efforts for the development of superannuated North general piers into a center of marine tourism and waterfront for the citizens of Busan. Recently it has moved to the stage of execution, after several trials to find concrete solutions. On the other hand, the change of flow field and tidal exchange cuased by redevelopment is one of the important investigation subjects. This study deals with the change of flow field and water exchange after redevelopment using numerical simulation technique, based on the general data which were collected and analyzed. As a result of simulation, the speed of tidal currents are tended to decrease near the North and inner-port and increase at the main waterway. Furthermore, the tidal exchange had a tendency to be small both before and after redevelopment by about 77% in a quasi steady state, which is about 15 days after.

• Polymer(Korea)
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• v.26 no.1
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• pp.105-112
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• 2002

The low actuation voltage and quick bending response of IPMC(ion-exchange polymer metal composite) are considered attractive for the construction of various types of actuators. In this study, in order to develop a new type actuators by using the IPMC platinum electrode of IPMC are fabricated by using electroless impregnation-reduction method plating. As the platinum-plating times are increased, IPMC performance was improved in terms of bending displacement and force due to the enhanced surface conductivity. In addition, we investigated the basic actuation characteristics of resonance frequency and actuator length as well as the effect of water uptake and ion mobility. Using the classical laminate theory(CLT), a modeling methodology was developed to predict the deformation, bending moment, and residual stress distribution of anisotropic IPMC thin plates. In this modeling methodology, the internal stress evolved by the unsymmetric distribution of water inside IPMC was quantitatively calculated and subsequently the bending moment and the curvature were estimated for various geometry of IPMC actuator.