• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.369-373
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• 2008

Special concern has been given to the elevated arsenic content in soils because of its high mobility and toxicity. Layered double hydroxide (LDH) which has a high anionic exchange capacity is another potential anion adsorbent for toxic anions such as arsenic, chromate and selenium etc. The uptake of arsenate from aqueous solutions by the calcined Mg-Al LDH has been investigated. The sorption capacity was about 530 mmol/kg. Sorption isotherm was defined as L-type in which arsenate was removed by LDH through anion uptake reaction. Arsenate sorption by the calcined Mg-Al LDH was occurred by reconstruction of LDH's framework. Competitive adsorption revealed that Mg-Al LDH had higher selectivity for arsenate than for sulfate. These results strongly suggest that calcined Mg-Al LDH has a promising potential for efficient removal of toxic metal oxides like arsenates from aqueous environments.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.279-288
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• 1996

Chronic exposure to cadmium impairs various renal tubular functions, including organic acid (anion) secretion. To investigate the mechanism of cadmium-induced alterations in the organic anion transport system, kinetics of p-aminohippurate (PAH) uptake was studied in renal cortical basolateral membrane vesicles (BLMV) isolated from cadmium-intoxicated rats (adult male Sprague-Dawley). Cadmium intoxication was induced by subcutaneous injections of $CdCl_{2}$ (2 mg Cd/kg per day) for 3 weeks. The renal plasma membrane vesicles were prepared by Percoll gradient centrifugation. The vesicular uptake of $^{14}C$-PAH was determined by rapid filtration technique using Millipore filter. Cadmium intoxication resulted in a marked attenuation of $Na^{+}$-dependent, ${\alpha}$-ketoglutarate (${\alpha}$KG)-driven PAH uptake with no changes in $Na^{+}$ and ${\alpha}$KG-independent transport component. Kinetic analysis indicated that Vmax, but not Km, of the $Na^{+}$-dependent, ${\alpha}$KG-driven component was reduced. A similar reduction of $Na^{+}$-dependent, ${\alpha}$KG-driven PAH uptake was observed in normal membrane vesicles directly exposed to inorganic cadmium in vitro, and this was accompanied by an inhibition of both $Na^{+}$-dependent ${\alpha}$KG uptake and ${\alpha}$KG-PAH exchange activity. These results indicate that during chronic exposure to cadmium, free cadmium ions liberated in the proximal tubular cytoplasm directly interact with the basolateral membrane and impair the active transport capacity for organic anions, most likely due to an inhibition of both $Na^{+}$-dicarboxylate cotransporter and dicarboxylate-organic anion antiporter activities.

• Analytical Science and Technology
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• v.12 no.2
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• pp.111-115
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• 1999

Single column anion chromatography by indirect UV detection was applied to the determination of 7 common anions($H_2PO_4^-$, $Cl^-$, $NO_2^-$, $NO_3^-$, $I^-$, $SO_4^{2-}$, $SCN^-$). A low capacity silica-based anion-exchange column(TSK guardgel QAE-SW; ca. 0.3 meq./g; 4.6 mm i.d${\times}$150 mm) was used. In separating common anions, we compared naphthalene trisulfonic acid(NTS) and naphthalene disulfonic acid(NDS) to find more sensitive, selective and rapid separation method. And cations and anions can be separated simultaneously in 0.20 mM NTS-5% acetonitrile-water.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.651-655
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• 1999

Xylenol Orange was bonded on an anion-exchange resin (Amberlite lRA 400, in $Cl^-$form) by batch equilibration. The resin was proved to be stable in acidic solutions of about 0.1 M HCl, $HNO_3$ or $H_2SO_4$. Sorption capacities for the metal ions on the Amberlite IRA 400 bonded with xylenol orange have been measured by batch method. The result showed that Fe(III) is higher than any other metals for sorption capacity. The preconcentration and the separation of Fe(lll) from the mixture soIution, therefore, were carried out with the 0.1 M sulfosalicylic acid as an eluent.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.172-176
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• 1998

An anion exchange resin which has Alizarin Red S (ARS) as functional group was prepared by batch method. The resin is stable in acidic solutions below 0.5 M hydrochloric acid, nitric acid and sulfuric acid and adsorption capacity of Fe(Ⅱ) ion on the resin was larger than other metal ions. The preconcentration and the separation of Fe(Ⅱ) ion from the mixture solution were carried out with the pH 4.5 buffer solution and 0.1 M $HNO_{3}$ as eluents.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.248-248
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• 2003

층상이중수화물(Layered Double Hydroxides, LDH)은 층 사이에 무기물 음이온이 있는 2차원 충상구조물로서 이들 층 사이의 공간에 이동 가능한 수화된 음이온의 존재로 전하균형을 이룬다. 층 사이의 음이온은 교환이 가능하며, 나머지의 공간은 물분자로 채워져 있다. 이러한 특성을 응용하여 LDH는 촉매, 음이온 교환제, 흡착제, 담체로 사용가능하며, 특히 음이온 교환능이 있는 소재로 고분자에 적용되고 있으며, 층간에 염료를 삽입한 복합체의 제조 둥에 관한 연구가 활발히 이루어지고 있다. 이의 적용에서 LDH의 입도는 결정적인 한계 요인으로 작용하기도 한다. 본 실험에서는 Mg-Al-NO$_3$ 층상이중수산화물(Mg-Al-NO$_3$-LDH)을 공침전법으로 합성하고, 양이온의 농도와 공침시 pH 및 교반조건의 변화가 생성된 LDH의 결정상, 형상, 입도, 및 양이온교환능에 미치는 영향을 알아보았다. 특히 초음파 분산법을 적용하는 경우 생성되는 LDH 입자크기의 미세화에 효과적인 것을 확인 할 수 있었다.

• KSBB Journal
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• v.9 no.2
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• pp.98-103
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• 1994

A bed configuration wherein sheets of modified fibrous polyethylene are potted within a Millipore Filter Cartridge matrix has been developed. Polyethylene fibers form sturdy beds but the native hydrophobicity and inertness of polyethylene have precluded their use in protein chromatography The polyethylene fibers used in this system were modified by plasma oxidation and further derivatization. The resulting fibers are hydrophilic, bind protein reversibly and serve as an anion-exchange stationary phase. Separation of Bovine Serum Albumin on this bed, as well as results of basic studies on capacity and reversibility of binding within a fibrous bed and experimental data handling system are shown.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.280-283
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• 2005

The adsorption of a model protein bovine serum albumin (BSA) in expanded bed chromatography was undertaken by exploiting a commercially available expanded bed column (20 mm i.d.) from UpFront Chromatography and Streamline DEAE $(\rho=1.2g/cm^3)$ from Amersham Pharmacia Biotechnology. The influence of whole yeast cells on the adsorption capacity of column was explored by employing yeast cells in a concentration ranged of 0 to $15\%(w/v)$. Equilibrium isotherms for adsorption of BSA on Streamline DEAE were correlated by using Langmuir equation. The presence of yeast cells resulted in decreased of BSA binding capacity in both batch binding and expanded bed chromatography. Results indicated that the yeast cells act as competitor for proteins to bind to the sites on adsorbents.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.868-873
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• 2019

In this study, the evaluation of performance of AORFB using methyl viologen and TEMPOL as organic active materials in neutral supporting electrolyte (NaCl) with various membrane types was performed. Using methyl viologen and TEMPOL as active materials in neutral electrolyte solution, the cell voltage is 1.37V which is relatively high value for AORFB. Two types of membranes were examined for performance comparison. First, when using Nafion 117 membrane which is commercial cation exchange membrane, only the charge process occurred in the first cycle and the single cell couldn't work because of its high resistance. However, when using Fumasep anion exchange membrane (FAA-3-50) instead of Nafion 117 membrane, the result was obtained as the totally different charge-discharge graphs. When current density was $40mA{\cdot}cm^{-2}$ and cut off voltage range was from 0.55 V to 1.7 V, the charge efficiency (CE) was 97% and voltage efficiency (VE) was 78%. In addition, the discharge capacity was $1.44Ah{\cdot}L^{-1}$ which was 54% of theoretical capacity ($2.68Ah{\cdot}L^{-1}$) at $10^{th}$ cycle and the capacity loss rate was $0.0015Ah{\cdot}L^{-1}$ per cycle during 50 cycles. Through cyclic voltammetry test, it seems that this difference in the performance between the full cell using Nafion 117 membrane and Fumasep anion exchange membrane came from increasing resistance due to chemical reaction between membrane and active material, not the capacity loss due to cross-over of active material through membrane.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.714-721
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• 2010

This research was undertaken to evaluate the feasibility of lanthanum hydroxide for fluoride removal from aqueous solutions. A batch sorption experiments were conducted to study the influence of various factors such as pH, contact time, initial fluoride concentration and temperature on the sorption of fluoride on lanthanum hydroxide. The optimum fluoride removal was observed in the $pH_{eq}{\leq}8.8$. Sorption equilibrium of fluoride on lanthanum hydroxide was better described by the Freundlish isotherm model than by the Langmuir isotherm model. The adsorption energy obtained from D-R model was 9.21 kJ/mol indicating an ion-exchange process as primary adsorption mechanism. The pseudo-second-order kinetic model described well the experimental kinetic data. Thermodynamic parameters such as ${\Delta}Go^{\circ}$, ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ indicated that the nature of fluoride sorption is spontaneous and endothermic. The used lanthanum hydroxide could be regenerated by washing with NaOH solution. Also, the results applied to real ground water indicate that fluoride selectivity and removal capacity of lanthanum hydroxide were superior to those of PA anion-exchange resin.