• Polymer(Korea)
• /
• v.27 no.1
• /
• pp.61-68
• /
• 2003

In this study, we have investigated the preparation of mixed bead and fiber type hybrid ion-exchanger for recovering nickel ion from plating rinse water. There was little dependence of adsorption capacity for nickel ion on the mixing ratio of resin type and fiber type of ion exchangers. However, it increased with increasing the resin content in the mixed bed. It was shown that the data Langmuir and Freundlich's adsorption isotherm model were well fitted to the linear. Affinity between the functional groups in the ion exchanger and nickel ion in the process was confirmed. The pressure drop decreased with increasing the number of stage in the multistage bed, but it increased with increasing the resin content in the mixing bed. The initial breakthrough time in the multistage bed was short due to the increase of number of stage in the continuous process. It was found that the final breakthrough time of the multistage bed was little changed. The breakthrough time decreased with increasing the amount of fibrous ion exchanger in the mixed bed. The maximum adsorption capacities of the mixed and multistage beds were 2.51 meq/g and 2.69 meq/g, respectively. The desorption time for the nickel ion with $1N H_2SO_4$ solution was lower than 10 minutes and the yield of desorption was greater than 98 percent.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6B
• /
• pp.677-682
• /
• 2006

Dodecyldimethylethylammonium (DDDEA), a cationic surfactant, and aluminum metal ions were used with bentonite to synthesize to synthesize an improved organo bentonite. Among three different synthesis procedure for organo bentonites, aluminium-pillared bentonite showed the highest DDDEA sorption, which indicated that aluminium-pillared organo bentonite would exhibit the highest sorption capacity for organic contaminants. Aluminium pillared organo bentonite also showed a high sorption capability for phosphorus, while it did not exhibit strong sorption for nitrate. In the meantime, more desorption was observed with aluminium-pillared organo bentonite than ordinary organo bentonites.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.5
• /
• pp.247-252
• /
• 2005

Soil pH is an intensity factor of releasing hydrogen ion which is buffered by aluminum. It depends on pH buffer capacity of Al whether soil pH is governed directly by cations or not. A study was conducted to elucidate the pattern of pH changes by soil EC. Fertilizer and three kinds of organic manures composed of cow and pig and fowl dropping and one kind of rice straw compost were added independently into upland sandy loam soil. This treated soils and four upland soils under plastic film house having different levels in electrical conductivity (EC) were incubated with field capacity at $30^{\circ}C$ for 5, 10, 20 and 40 days. Soil pH varied directly as the cations contained in organic materials according to degree of saturating pH buffer capacity (pBC) of sandy loam soil. pH of the soils under plastic film house was lowered by soil EC due to governing by overplus of cation beyond pBC.

• Progress in Medical Physics
• /
• v.17 no.2
• /
• pp.96-104
• /
• 2006

Experiments from several groups Including ours have demonstrated that $Ca^{2+}$ can enhance the inactivation of N-type calcium channels. However, it is not clear if this effect can be ascribed to a 'classic' $Ca^{2+}$-dependent inactivation (CDI) mechanism. One method that has been used to demonstrate CDI of L-type calcium channels is to alter the intracellular and extracellular concentration of $Ca^{2+}$. In this paper we replaced the external divalent cation to monovalent ion ($MA^+$) to test CDI. In the previous paper, we could separate fast (${\tau}{\sim}150ms$) and slow (${\tau}{\sim}2,500ms$) components of inactivation in both $Ba^{2+}$ and $Ca^{2+}$ using 5-sec voltage step. Lowering the external divalent cation concentration to zero abolished fast inactivation with relatively little effect on slow inactivation. Slow inactivation ${\tau}$ correspond very well with provided the $MA^+$ data is shifted 10 mV hyperpolarized and slow inactivation ${\tau}$ decreases with depolarization voltage in both $MA^+\;and\;Ba^{2+}$, which consistent with a classical voltage dependent inactivation (VDI) mechanism. These results combined with those of our previous paper lead us to hypothesize that external divalent cations are required to produce fast N-channel inactivation and this divalent cation-dependent inactivation is a different mechanism from classic CDI or VDI.

• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.6
• /
• pp.533-544
• /
• 2021

Ion exchange (IX) performance on the exchanger bed is essentially evaluated for the generation of ultrapure water in electronics and chemical industries and for the corrosion control in nuclear power plants. The breakthrough characteristics of IX bed with multi-component were investigated with both cation- and mixed-IX beds of H- and ETAH-form for four kinds of cation exchange resins by using the combined solution of ethanolamine (ETA) and ammonia (NH₃) at trace NaCl. Unlike major components (ETAH⁺ and NH₄⁺ ), the phenomena of breakthrough and overshooting at bed outlet were not observed by Na⁺ over the test period (> 3 times theoretical exchange capacity of IX bed). The breakthrough from H-form resin bed was sequentially reached by ETAH⁺ and NH₄⁺, while the overshooting was observed for ETAH⁺ at the breakthrough of NH₄⁺. NH₄⁺ was 51.5% higher than ETAH⁺ in terms of the relative selectivity determined with the width of breakthrough zone. At the increased concentration of Na⁺ at bed inlet, the selectivity and the overshooting were decreased and increased, respectively. Na⁺ leakage was higher from ETAH-form resin bed and was not identical for four kinds of cation-exchange resins, which may be reduced by improving the intrinsic property of IX resin.

• Korean Journal of Mineralogy and Petrology
• /
• v.35 no.3
• /
• pp.345-353
• /
• 2022

This study aimed to fundamentally understand changes of cell parameters of cation-exchanged mordenites using high resolution X-ray powder diffraction for studies that immobilization of various heavy metal cation using synthesis mordenite (Na_6.6Al_6.6Si_41.4O₉₆·20.4H₂O, Na-MOR). As a results of measurement by Thermogravimetric analysis (TGA), it was confirmed that 19.4, 20.4 water molecules per unit cell were present in monovalent-cation substituted MOR (Cs-MOR, Na-MOR), and 21, 23.1, 23.2 water molecules per unit cell were present in divalent-cation substituted MOR (Pb-MOR, Sr-MOR, Cd-MOR). The space group of all the samples were identified as Cmcm belonging to the orthorhombic crystal system. Compared to Na-MOR, starting material, relative peak intensity of (110) and (200) is significantly changed after cation substitution whereas peak position is almost similar. Also, (220) peak that was not found in Na-MOR was clearly observed in Pb-, Cd- and Sr-exchanged MOR. Thus, it was estimated that changes of atomic distribution usually occurred on ab-plane while changes of cell parameters were little. Detailed changes in the cell parameters of cation-exchanged mordenites were derived from whole profile fitting method using the GSAS suite program. Changes in the axial lengths and unit cell volume of cation substitution showed different relationship depending on ionic radius and charge number. In case of monovalent-cation substituted MOR, the length of a-axis increases whereas the length of b- and c-axis decrease by absorbed cation radius. In the case of divalent-cation exchanged MOR, the length of a-axis usually decreases while the length of b- and c-axis increases by cation radius. It was confirmed that unit cell volume of monovalent and divalent cation substituted MORs had an independent tendency by cation radius.

• Journal of the Korean Chemical Society
• /
• v.28 no.1
• /
• pp.62-69
• /
• 1984

The reaction of toluene with ethanol was studied over various cation-exchanged pentasil zeolite catalysts. The toluene disproportionation reaction to produce xylenes increased with increasing reaction temperature and the activity of alkylation of toluene with ethanol showed maximum at around $400^{\circ}C$. Only Cs-ZSM-5 catalyst showed pronounced p-ethyltoluene selectivity increasing to 96% with increasing degree of Cs-exchange. The sorption rate of m-xylene was lower for Cs-exchanged ZSM-5 than H-ZSM-5 catalyst. These phenomena were interpreted in terms of shape selectivity arising from the partial blocking of channel intersections by large cesium ions.

• Journal of Adhesion and Interface
• /
• v.7 no.1
• /
• pp.3-9
• /
• 2006

Three isocyanate groups of IP-$75^{(R)}$ and one hydroxyl group of various amino alcohols were applied for preparing cationic type water-borne polyurthane (PU) having ionic center onto flexible side chains. Average particle size, dispersion stability, viscosity, contact angle, surface energy, glass transition temperature ($T_g$), and adhesion strength of prepared water-borne PUs were measured and analyzed with different NCO/OH mol ratios, ionomers, and neutralizing agents. It was characterized that the prepared PU has a smaller particle size and a better dispersion stability than the conventional cationic water-borne PU containing ionic centers onto main chains.

• KSBB Journal
• /
• v.7 no.3
• /
• pp.209-215
• /
• 1992

The aims of this sutdy was to investgate the action mechanism of polycation on the $\beta$-glucan synthetase II (GS II) related to cell wall synthesis in suspension cultured carrot cells. In the suspension cultured cells treated with poly-L-Iysine($12{\mu}M$) and poly-L-ornithine ($12{\mu}M$) having ploycationic nature, GS II activity increased about 40% and 50% than that of the control respectively. And similar response was observed when ATP and NaF were treated. On the other hand, ploy-L-lysine and ploy-L-ornithine did nor affect the membrane permeability. Phorbol-12-myrlstate-13-acetate (TPA), activator of protein klnase, increased about 35% and 1-(5-isoquinolinyl sulfonyl)-2-methyl-piperrazine (H-7), inhibitor of protein kinase, decreased about 30% of GSII activity than that of control. These results suggest that polycation plays a role in the cell wall synthesis by increasing GS II activity through phosphorylation.

• Applied Chemistry for Engineering
• /
• v.19 no.5
• /
• pp.533-538
• /
• 2008

In order to enhance the adsorption capacity of $CO_2$, a commercial zeolite and coal fly ash were chemically modified with alkali cations (Li, K) and alkaline-earth cations (Ca, Mg). Adsorbents containing Ca and Mg showed slightly lower surface areas. The adsorption capacity at the ambient temperature was highest with Ca, then in order of Mg, Li, and K. On the contrary, regeneration efficiency of the adsorbents with Ca and Mg was relatively low, because Ca and Mg cations had stronger affinity of carbon dioxide. The affinity between cations and $CO_2$ molecule also may improve the selectivity in favor of $CO_2$ adsorption.