• Membrane Journal
• /
• v.25 no.6
• /
• pp.515-523
• /
• 2015

While commercial polystyrene-based ion exchange membranes have simple manufacturing processes, they also possess poor durability due to their brittleness. Poly(ethylene glycol)methyl ether methacrylate with hydrophilic side chains of poly(ethylene glycol) was used as a co-monomer to make the membranes have improved flexibility. Hydrophilicity/hydrophobicity of the anion exchange membranes were able to be adjusted by varying the chain lengths of the poly(ethylene glycol). For the preparation of the anion exchange membranes, a porous PE substrate was immersed into monomer solutions and thermally polymerized. The prepared membranes were subsequently reacted with trimethylamine to produce anion exchange functional groups, Quaternary ammonium salts. The prepared pore-filled anion exchange membranes were evaluated in terms of ion exchange capacity, electric resistance, elongation at break and water uptake.

• Membrane Journal
• /
• v.20 no.4
• /
• pp.290-296
• /
• 2010

Ethylene vinyl acetate (EVA-28)/Co-Al LDH nanocomposite membranes were prepared by solution intercalation using organically modified LDH. LDH was made organophilic by the intercalation of dodecyl sulfate (DS) anion in the interlayer. The prepared membranes were characterized using XRD, FT-IR and SEM. Gas permeability of EVA/LDH nanocomposite membranes with LDH content of 1, 3, and 5 w% was studied for $O_2$ and $CO_2$ at pressure of 3, 4, and 5 bar. The permeability of $O_2$ and $CO_2$ was minimum for nanocomposite membrane with 1 wt% LDH and increased with increasing LDH content, which is presumably due to aggregation of LDH filler. The selectivity of $CO_2$ for $O_2$ showed the maximum value at 1 wt% of LDH content and decreased thereafter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.7
• /
• pp.563-566
• /
• 2013

We investigated the variation of anion exchange membrane of hydrogen generator of alkaline electrolysis. We detected the variation of elements and change of anion exchange membrane using EDS and FE-SEM. We detected two different sites of membrane because of different structure of membrane. $Sp_1$ shows that the distribution ratio of C, O, Al is 98% very higher than $Sp_2$ of 78%. Especially, the main elements of STS316 which is P, S, Fe, Ni were more detected at $Sp_2$ than $Sp_1$. We think that this result depends on the structure of membrane. This also affect the resistance, lifetime of membrane and decrease the efficiency of hydrogen production. We hope that this article is a foundation of developing of hydrogen production technology.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2247-2248
• /
• 2013

• Korean Chemical Engineering Research
• /
• v.46 no.3
• /
• pp.492-497
• /
• 2008

The solubility of carbon dioxide in ionic liquids and amine solvents has been investigated in gas-liquid absorption equilibrium reactor. Absorption capacity and kinetics of $CO_2$ with $CO_2$ pressure and absorption time in 9 different ionic liquids and 2 kinds of amine solvents were evaluated. In order to understand the effect of ionic type, we changed the cation or anion of ionic liquids. $CO_2$ absorption capacity and absorption rate of amine solvents were higher than those of ionic liquids. $CO_2$ absorption capacity of [emim][$Tf_2N$], $0.14molCO_2/mol\;IL$ at 1 bar, was the highest among the ionic liquids. $CO_2$ absorption capacity of ionic liquid steeply decreased with increasing temperature. Anion of ionic liquid dominates interaction with $CO_2$ and cation plays secondary role.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.06a
• /
• pp.248-254
• /
• 2005

This paper presents a quantitative method of sequential separation of $^{90}Sr,\;^{241}Am$ and Pu nuclides with an anion exchange resin and a Sr-Spec resin. The Pu isotopes were purified with an anion exchange resin. The americium and strontium fractions were separated from the matrix elements with an oxalate co-precipitation method. Americium fraction was separated from the strontium fraction with iron co-precipitation method and purified from lanthanides with anion exchange resin. Strontium-90 was purified from other hindrance elements with the Sr-Spec resin after oxalate co-precipitation. The measurement of Pu and Am isotopes was carried out by an ${\alpha}$-spectrometer. Strontium-90 was measured by a liquid scintillation counter. The radiochemical procedure of $^{90}Sr,\;^{241}Am$ and Pu nuclides investigated in this study has been validated by application to IAEA-Reference soils.

• Applied Chemistry for Engineering
• /
• v.25 no.6
• /
• pp.559-563
• /
• 2014

It is well known that $CO_2$ can be dissolved easily in imidazolium-based room temperature ionic liquids (RTILs). Because of the high $CO_2$ solubility in RTILs, membranes containing RTILs can separate easily gas mixtures such as $CO_2/N_2$ and $CO_2/CH_4$. In this study, we prepared poly(vinylidene fluoride)-hexafluoropropyl copolymer (PVDF-HFP) gel membranes with several RTILs and measured permeabilities of several gases. When the anion of ionic liquids was tetrafluoroborate($BF{_4}^-$), both $CO_2$ permeability and selectivities decreased as the carbon number of the cation increased. When the cation of ionic liquids was 1-ethyl-3-methylimidazolium[emim], $CO_2$ permeability of gel membranes containing bis(trifluoromethane) sulfoneimide($Tf_2N^-$) anion was double compared to those containing tetrafluoroborate($BF{_4}^-$) anion. However, $CO_2/N_2$ and $CO_2/CH_4$ selectivities of the $Tf_2N^-$ case were decreased, whereas the $H_2$ selectivity was almost the same for two cases.

• Journal of the Korean Electrochemical Society
• /
• v.2 no.4
• /
• pp.183-189
• /
• 1999

A study on the destruction of organic cation and anion exchange resins by electro-generated Ag(II) as a mediator was carried out to develop the ambient-temperature aqueous process, known as Ag(II)-mediated electro-chemical oxidation (MEO) process, for the treatment of a large quantity of spent organic ion exchange resins as the low and Intermediated-level radioactive wastes arising from the operation, maintenance and repairs of nuclear facilities. The effects of controllable process parameters such as applied current density, temperature, and nitric acid concentration on the MEO of organic ion exchange resins were investigated. The cation exchange resin was completely decomposed to $CO_2$. The current efficiency increased with a decrease in applied current density while nitric acid concentration and temperature on the MEO of cation exchange resin did not affect the MEO. On the other hand, anion exchange resins were decomposed to CO and $CO_2$. The ultimate conversion to CO was about $10\%$ regardless of temperature. The destruction efficiencies to $CO_2$ were dependent upon temperature and the effective destruction of anion exchange resin could be obtained above $60^{\circ}C$.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.71-76
• /
• 2011

An efficient nucleophilic [$^{18}F$]fluorination has been studied to reduce byproducts and preparation time. Instead of conventional aqueous solution of $K_2CO_3-K_{222}$, several organic solution containing inert organic salts were used to release [$^{18}F$]fluoride ion and anion bases captured in the polymer cartridge, concluding that methanol solution is the best choice. Comparing to azeotropic drying process, one min was sufficient to remove methanol completely, resulting in about 10% radioactivity saving by reducing drying time. The polymer cartridge, Chromafix$^{(R)}$ (PS-$HCO_3$) was pretreated with several anion bases to displace pre-loaded bicarbonate base. Phosphate bases showed better results than carbonate bases in terms of lower basicity. tert-Butanol solvent used as a reaction media played another critical role in nucleophilic [18F]fluorination by suppressing eliminated side product. Consequent [$^{18}F$]fluorination under the present condition afforded fast preparation of reaction solution and high radiochemical yields (98% radio-TLC, 84% RCY) with 94% of precursor remained.

• Journal of Environmental Health Sciences
• /
• v.18 no.1
• /
• pp.39-46
• /
• 1992

It has known that the intermediates formed in acid reactions occuring during anaerobic reactions for instance, acetic acid, propionic acid and butyric acid have significant effects or the formations of biogases(e. g. mainly CH$_{4}$ and CO$_{2}$). A study on the effects of these intermediates for the formations of biogases, however, is still on initial stage due to the type and structural problems of reactor. The primary objective of this reserch program is to provide a funadmantal mechanism of involved reactions using a modified downflow multistage pecked bed bioreactor. As a first stage of this reaserch program, the following theoretical principles was applied 1. Principle of electroneutrality where the molar concentrations of cation and anion in solution are the same. 2. Relationship between the concentration of bicarbonate anion and pH as follows [HCO$_{3}^{-}$]= $K_{H}P_{T}Y_{CO_{2}}10^{pH-K_{1}}$ Based upon the above two principles, a series of experimental works was conducted to elucidated the relationship between the concentration of CO$_{2}$ and the pH related to the concentrations of cations and anions.