• Korean Membrane Journal
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• v.9 no.1
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• pp.18-26
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• 2007

The transport and removal characteristics of cobalt ions were investigated in a continuous electrodeionization with cation exchange textile (CEDI-CET). It was shown that the removal properties of cobalt ions are strongly dependent on the operating parameters such as temperature, flow velocity, and the solution pH. The transport and removal of cobalt ions was mainly related to the sorption on the surface and the convection and electro-migration through the ion exchange medium. In this study, the CEDI-CET showed good process performance for the removal of metal ions compared with the conventional CEDI with resins.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.653-662
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• 2017

Copper(II) acetate spectrophotometry method (CASM) was used for the rapid and convenient determination of cation exchange capacity (CEC) in soils. This method is composed of a single-step exchange reaction that adsorbs copper and is measured through spectrophotometry. The CEC of 16 Korean soils were measured using 1M ammonium acetate method (AAM) and the CASM. The CEC values determined by CASM and AAM were not significantly different, and were highly correlated ($r=0.966^{**}$). Due to the convenience, cost effectiveness, and time saving analysis of CASM, this method is recommended for most soil laboratories to measure CEC in Korean soils. However, CASM may not be applicable for soils that have a much higher CEC (greater than $20cmol_c\;kg^{-1}$).

• Macromolecular Research
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• v.16 no.1
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• pp.21-30
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• 2008

Based on the sheath-core bicomponent composite fibers with modified polystyrene (PS) and the modified polypropylene (PP), composite fibers obtained were further cross-linked and sulphonated with chlorosulphonic acid to produce strong acidic cation ion exchange fibers. The structures of the fibers obtained were characterized using Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) etc. The optimal technology of the fibers obtained is discussed. The static absorption capacity of the sheath-core bicomponent composite cation exchange fibers for $Zn^{2+}$, $Cu^{2+}$ was determined. The absorption kinetics and major factors affecting the absorption capacities of $Zn^{2+}$, $Cu^{2+}$ were studied, and its chemical stability and regenerating properties were probed. The results suggest that cation exchange fibers with better mechanical properties and higher exchange capability were obtained. Moreover, this type of ion exchange fiber has good absorption properties and working stability to various metal ions. Hence, they have higher practicability.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.341-343
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• 2018

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.156-159
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• 2002

Ion exchange is the most reliable process to remove the ionic impurities and the economic operation. ion exchange is widely used in water and wastewater treatment, especially softening and demineralization. ion selectivity depends on the hydrated radius, charge of ions and concentration. The objective of this study was to determine the selectivity order of cations with equilibrium and column ion exchanges and to investigate the effect of the background anion on selectivity. Cation selectivity increases with decreasing concentration and increasing charge ( $H^+$ < $K^+$ << $Cu^{2+}$ < $Co^{2+}$ < TEX>$Ca^{2+}$ << $Ce^{3+}$)in equilibrium and column cation adsorptions.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.331-337
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• 2017

Proton Exchange Membrane Water Electrolysis (PEMWE) is one of the most popular and widely used methods for hydrogen production. PEMWE contributes to eco-friendly system via its energy storage system application, hence making it environmentally friendly to use. However, its main drawback is contamination of proton exchange membrane during water electrolysis. Existing cation such as magnesium, calcium and the likes are the cause for membrane contamination. As a result, the cation contamination give rise to degradation of performance of electrolysis and the reverse electrolysis is effective method to remove cation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.79-86
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• 2005

In PSR on the Kori 3&4 NPP, The low level radioactive waste resin from SGBD demineralizer is more than $65\%$ of total waste resin in NPP So, it needs to be improved. The secondary cooling water pH control methods are used ammonia-AVT from the first. According to changing ETA which is better than ammonia, SGBD cation load is increased about 2-3 times. Waste resin product is also increased in proportion to the SGBD cation load. To reduce the waste volume, new cation resin exchange criteria is confirmed that demineralizer is almost saturated.

• Nuclear Engineering and Technology
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• v.9 no.2
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• pp.75-81
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• 1977

This experiment has been carried out to determine the pH dependent cation exchange capacity concerning the sorption phenomenon of long-lived radionuclides contained in low-level liquid radioactive waste on various clay minerals. The pH dependent cation exchange capacity determined by Sawhney's method are used to the analysis of sorption phenomenon. About 70 percent of the total cation exchange capacity is contributed by the pH dependent CEC due to the negative charge originated naturally in clays in case of clinoptilolite, vermiculite and sodalite. It is sugested in this test that the high neutral salt CEC, that is, highly charged clays would show good fixation yield. The removal of radionuclides at the pH range more than pH 9 is considered the hydroxide precipitation of metal ion rather than the cation exchange. The Na-clay prepared by the method of successive isomorphic substitution with electrolyte showed a considerable improvement in removal efficiency for the decontamination.

• Journal of Forest and Environmental Science
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• v.37 no.2
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• pp.116-127
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• 2021

Predicting carbon distribution of soil aggregates is difficult due to complexity in organo-mineral formation. This limits global warming mitigation through soil carbon sequestration. Therefore, knowledge of land use effect on carbon stabilization requires quantification of soil mineral cations. The study was conducted to quantify carbon and base cations on soil mineral fractions in Natural Forest, Plantation Forest and Farm Land. Five 0.09 ha were demarcated alternately along 500 m long transect with an interval of 50 m in Natural Forest (NF), Plantation Forest (PF) and Farm Land (FL). Soil samples were collected with soil cores at 0-15, 15-30 and 30-45 cm depths in each plot. Soil core samples were oven-dried at 105℃ and soil bulk densities were computed. Sample (100 g) of each soil core was separated into >2.0, 2.0-1.0, 1.0-0.5, 0.5-0.05 and <0.05 mm aggregates using dry sieve procedure and proportion determined. Carbon concentration of soil aggregates was determined using Loss-on-ignition method. Mineral fractions of soil depths were obtained using dispersion, sequential extraction and sedimentation methods of composite soil samples and sieved into <0.05 and >0.05 mm fractions. Cation exchange capacity of two mineral fractions was measured using spectrophotometry method. Data collected were analysed using descriptive and ANOVA at α_0.05. Silt and sand particle size decreased while clay increased with increase in soil depth in NF and PF. Subsoil depth contained highest carbon stock in the PF. Carbon concentration increased with decrease in aggregate size in soil depths of NF and FL. Micro- (1-0.5, 0.5-0.05 and <0.05 mm) and macro-aggregates (>2.0 and 2-1.0 mm) were saturated with soil carbon in NF and FL, respectively. Cation exchange capacity of <0.05 mm was higher than >0.05 mm in soil depths of PF and FL. Fine silt (<0.05 mm) determine the cation exchange capacity in soil depths. Land use and mineral size influence the carbon and cation exchange capacity of Gambari Forest Reserve.

• Membrane Journal
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• v.22 no.4
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• pp.265-271
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• 2012

Polybenzimidazole (PBI) was prepared by condensation polymerization using diaminobenzidine (DAB) and isophtalic acid (IPAc). The cation exchange membrane was prepared by introduce the ion exchange group in the PBI polymer. It was confirmed from FT-IR analysis that the prepared PBI powder had same peak compared with commercial PBI power. The ionic conductivity of PBI film was $0.1{\sim}0.9{\times}10^{-2}$ S/cm. The ionic conductivity of prepared SPBI cation exchange membrane showed $3.7{\sim}4.7{\times}10^{-2}$ S/cm and had higher than Nafion117 ($2.0{\times}10^{-2}$ S/cm).