• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.255-260
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• 2011

$NH_4{^+}-{\beta}^{{\prime}{\prime}}$-alumina which is expected to an inorganic solid electrolyte of high temperature polymer electrolyte membrane fuel cells (PEMFC) was prepared by ion-exchange reaction of $K^{+}-{\beta}^{{\prime}{\prime}}$-alumina pellet with $NH_4NO_3$ aqueous solution and molten $NH_4NO_3$ salts as an ion-exchange medium in the autoclave and the heating mentle reaction. In the autoclave reaction, the concentrations of $NH_4NO_3$ solution was chosen at 5 and 10 M. Each ion-exchange reaction was carried out at 130, 150, 170, and $200^{\circ}C$ for 2, 4, 6 and 8 h. In the heating mentle reaction, ion-exchange was performed at $200^{\circ}C$ for 2, 4, 6 and 8 h with molten $NH_4NO_3$ salts. In order to determine the effect of reaction times, each ion-exchange reaction was repeated 3 times. The phase stability and the ion-exchange rate of $NH_4{^+}-{\beta}^{{\prime}{\prime}}$-alumina were analyzed by XRD and ICP.

• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.21-27
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• 2018

BACKGROUND: Although 1 M $NH_4OAc$ (pH 7.0) is predominantly used as the extractant of exchangeable cations in agricultural soils, this method is unsuitable for extracting the cations in saline and calcareous soils. This study was performed to select a proper method to determine exchangeable cations in vinyl greenhouse soils. METHODS AND RESULTS: Exchangeable cations (Ca, Mg, K, Na) in saline vinyl greenhouse soils were determined after extraction with 1 M $NH_4OAc$ (pH 7.0 and 8.5) and 1 M alcoholic $NH_4Cl$ (pH 8.5). Sum of exchangeable cations of the soils extracted with 1 M $NH_4OAc$ at pH 7.0 was 1.9-2.5 times greater than soil cation exchange capaity determined at pH 7.0, even though soluble salts were pre-removed. A similar result was found when the cations were extracted with 1 M $NH_4OAc$ at pH 8.5. Those results are mostly due to the overestimation of exchangeable Ca and Mg, linked to a partial dissolution of sparingly soluble salts in $NH_4OAc$ solution. When extracted with 1 M alcoholic $NH_4Cl$ at pH 8.5, extractable Ca and Mg decreased significantly due to the lower solubility of Ca and Mg carbonates in the extractant. And the sum of exchangeable cations was very close to the corresponding exchange capacity of soils. CONCLUSION: Alcoholic $NH_4Cl$ (pH 8.5) is proposed as a reliable extractant in determination of exchangeable cations in saline vinyl greenhouse soils. And soluble salts should be removed prior to the extraction of exchangeable cations.

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

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.232-237
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• 1989

The elution mechanism of rare earth elements in cation exchange resin which was substituted with $NH_4^+,\;Zn^{2+}\;or\;Al^{3+}$ as a retaining ion had been investigated. Rare earths or rare earths-EDTA complex solution was loaded on the top of resin bed and eluted with 0.0269M EDTA solution. When the rare earth-EDTA complex was adsorbed on the $Zn^{2+}\;or\;Al^{3+}$ resin form, retaining ion was complexed with EDTA and liberated rare earths was adsorbed in the resin again. Adsorbed rare earths in resin phase could be eluted by the complexation reaction with EDTA eluent. On $NH_4^+$ resin form, the rare earth-EDTA complex which had negative charge could not adsorbed on the cation exchange resin because the complexation reaction between $NH_4^+$ and EDTA was impossible. So the elution time was much shorter than in $Zn^{2+}\;or\;Al^{3+}$ resin form. When the rare earths solution was loaded on the $Zn^{2+},\;Al^{3+}$ resin form bed, rare earths was adsorbed in the resin and the retaining ion was liberated. Adsorbed rare earths in resin bed was exchanged by EDTA eluent forming rare earths-EDTA complex, and eluted through these processes. On $NH_4^+$ resin form, rare earths loaded was adsorbed by exchange reaction with $NH_4^+$. As the EDTA eluent was added, rare earths was liberated from resin forming negatively charged rare earth-EDTA complex and eluted without any exchange reaction. So the elution time was greatly shortened and there was no metallic ion except rare earths in effluent. When the $Zn^{2+}\;and\;Al^{3+}$ was used as retaining ion, the pH of efflent was decreased seriousely because the $H^+$ liberated from EDTA molecule.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.969-973
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• 1999

In this work, we studied the degree of hydrolysis of ion exchanger in $NH_4OH$ solution and sorption characteristics of $NH_3$ by potentiometric titration curves with using carboxylic acid ion exchanger Fiban K-4. We knew that the theoretical pH values agreed with the experimental pH values on the $NH_4OH$ concentrations in various concentrations of supporting electrolyte $(NH_4)_2SO_4$. The sorption values of $NH_3$ using the ion exchanger can be calculated from equivalent sorption curves for various pH. Also, the degree of hydrolysis increased with decreasing concentration of supporting electrolyte and pH. In order to obtain the mono ion form below 0.01 M as the decreasing concentration of supporting electrolyte, the pH values should be increased. From these results, therefore, the concentrations of supporting electrolyte and pH values were determined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.296-300
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• 2003

A large equilibrium and kinetic data set for multi-component cation exchanges was obtained and tested with mass action law and surface complexation model. The systematic batch equilibrium and column experiments of cation adsorption were conducted for binary, ternary, quaternary, and quinary cation exchanges involving $ H^{+}, Li^ {+}, Na^{+}, NH$_4$^{+}, Mg^{2+} $ on a strongly acidic cation exchange resin IRN 77. The mass action law and surface complexation model were tested against both data set to investigate the consistency of ion selectivity and their predictability for competitive cation exchanges. Surface complexation model provided more accurate predictions for both equilibrium and kinetic experimental data than mass action model.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.553-559
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• 1991

The elution characteristics of rare earth elements in $NH^{4+}$ form cation exchange resin had been investigated. Elution were performed varing the loading amount, column diameter, column length and eluent pH. Analysing the chemical species contained in each effluent, elution mechanisms of rare earth elements and the separation of rare earth elements in monazite could be understood. The resolution values of adjacent rare earth elements were improved increasing rare earths adsorption amount wfith the same column within it's exchange capacity. With $NH^{4+}$ resin form, column length does not affect on the resolution values and retention time of rare earth elements and the rare earth-EDTA complex were not adsorbed on $NH^{4+}$ resin form. pH of eluent affected on the reactivities between rare earth elements and EDTA. Decreasing eluent pH, resolution values of adjacent rare earth elements were increased while increasing elution time.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.775-782
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• 2009

PP-g-AA-Am nonwoven fabric, which possess anionic exchangeable function, was prepared by chemical modification of carboxyl (-COOH) group of PP-g-AA nonwoven fabric to amine ($-NH_2$) group using diethylene triamine (DETA). Its adsorption characteristics for anionic nutrients including isotherm, kinetics and co-anions were studied by batch adsorption experiments. Adsorption equilibriums of $PO_4$-P on PP-g-AA-Am fabric were well described by the Langmuir isotherm model, and their adsorption energies were ranged 10.3 kJ/mol indicating an ion-exchange process as primary adsorption mechanism. The adsorption selectivity of PP-g-AA-Am nonwoven fabric for anions under competition with each other was in following order: $SO_4\;^{2-}$>$PO_4\;^{3-}$>$NO_3\;^-$>$NO_2\;^-$. Also, all results obtained from this study indicate that the $PO_4$-P removal capacity of PP-g-AA-Am nonwoven fabric was extremely superior to that of PA308 anion-exchange resin.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.43-50
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• 1996

A series of domestic natural zeolites were investigated to identify the phase and to study the capability of $NH_4{^+}$-ion removal from solution system. It was proved that the natural zeolite from Young-II bay area was thermally unstable zeolite, heulandite by XRD and FT-IR analyses. In addition, the heulandite exchanged by $K^+$ ion showed the highest thermal stability upon heat-treatments. However, the best capability of removing $NH_4{^+}$-ion from the solution system was the non-exchanged zeolite.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.307-311
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• 2003

The test did for the determine the optimized ratio of cation to anion in mixed ion exchange demineralizers. Binary, ternary, quaternary, and quinary cation and anion adsorption was performed to develop a comprehensive experimental data set from small-volume batch tests to obtain the selectivity coefficients of many cations and anions. The quantitative run time might be estimated by such ion exchange models as semi-empirical mass action and surface complexation models. The demineralizer can be used longer by increasing the ratios of cation to anion exchange resins in the bed.