• 한국재료학회지
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• 제26권9호
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• pp.498-503
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• 2016

The characteristics of aqueous lithium recovery by ion exchange were studied using three commercial cation exchange resins: CMP28 (porous type strong acid exchange resin), SCR-B (gel type strong acid exchange resin) and WK60L (porous type weak acid exchange resin). CMP28 was the most effective material for aqueous lithium recovery; its performance was even enhanced by modifying the cation with $K^+$. A comparison to $Na^+$ and $H^+$ form resins demonstrated that the performance enhancement is reciprocally related to the electronegativity of the cation form. Further kinetic and equilibrium isotherm studies with the $K^+$ form CMP28 showed that aqueous lithium recovery by ion exchange was well fitted with the pseudo-second-order rate equation and the Langmuir isotherm. The maximum ion exchange capacity of aqueous lithium recovery was found to be 14.28 mg/g and the optimal pH was in the region of 4-10.

• 한국환경과학회지
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• 제11권3호
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• pp.263-269
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• 2002

This study was conducted to know the removal characteristics of ammonia nitrogen by commercially available cation exchange resins. Eight acidic cation exchange resins were investigated in batch reactors. Among them, the most effective resin for ammonia removal in solution was PK228, which was a strong acidic resin of $Na^{+}$ type. PK228 was compared with activated carbon and natural zeolite. The effects of cation exchange capacity, ammonia concentration, resin amount, temperature and pH on ammonia removal by PK228 were investigated in batch reactor, and the effect of effluent velocity in continuous column reactor. Strong acidic resins of porous type were more effective than week acidic resins or gel type resins for ammonia removal in solution. PK228 was more effective than activated carbon and natural zeolite for ammonia removal in batch reactor. With increasing initial ammonia concentration, the amount of ammonia removed by PK228 increased, but the proportion of removed ammonia to initial ammonia concentration decreased. The effect or temperature on ammonia removal by PK228 was very slight. The ammonia removal to acidic solution was more effective than that at basic solution. With decreasing effluent velocity of solution through column, breakthrough point extended, and ammonia removal capacity increased.d.

• Bulletin of the Korean Chemical Society
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• 제6권4호
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• pp.225-228
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• 1985

The absorptions of Fe(Ⅲ), Tb(Ⅲ), Tl(Ⅰ), Ce(Ⅲ), Th(Ⅳ), and $UO_2^{2+}$ ions into the Dowex 50W-X2, 100-200 mesh resin were investigated by spectrophotometry to understand the abnormal strong absorption behavior of cations to cation exchange resins in concentrated HClO4. The distribution coefficients increase in the order : Tl(Ⅰ) < Fe(Ⅲ) < Tb(Ⅲ)∼Ce(Ⅲ) < $UO_2^{2+}$< Th(Ⅳ) and the order is interpreted in terms of the ratio of charge-to-ionic radius. The mole ratios of increment of $ClO_4^-$ ion absorption to metal ion absorption showed the same order as the distribution coefficients, which indicates that the electrostatic association between $ClO_4^-$ ion and metal ion plays a major role in the strong absorption.

• 약학회지
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• 제59권3호
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• pp.113-119
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• 2015

Protein phosphorylation is one of most important post-translational modifications (PTMs) and plays an important role in regulation of protein function. Here we develop a method for a global identification of phosphopeptides and phosphorylation sites using nano-LC MS/MS. We compared two separation methods, C4 and strong cation ion exchange (SCX). Before phosphopeptides enrichment with $TiO_2$, total proteins from Rat 1 cells have been separated using C4 column or tryptic peptides of proteins from the cells have been separated using SCX column. Finally, we have detected 52 phosphorylation sites on 41 proteins from SCX method and 375 phosphorylation sites on 252 proteins from C4 method, and determined the function and localization of identified phosphoproteins using DAVID software. In particular, we showed new phosphorylation sites from membrane proteins related to various cell signaling mechanisms. This method may contribute to study global signal networks induced by various signals including ligands and drugs.

• Macromolecular Research
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• 제16권1호
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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.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.339-341
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• 2008

Catalytic trimerization of isobutene to produce triisobutenes has been performed over cation-exchange resin and zeolite catalysts. Resin catalysts have the advantage of long lifetime and high trimers selectivity even though the regeneration of an aged catalyst is not satisfactory. On the contrary, zeolite catalysts can be regenerated facilely by simple calcination in air even though the lifetime is short and trimers selectivity is low probably due to small pore size and strong acidity, respectively. It is, therefore highly desirable to develop an inorganic acid catalyst with macro- or meso-pores to show catalytic performances similar or superior to those of macroporous resin catalysts.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3298-3302
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• 2012

Although offline enrichment of phosphorylated peptides is widely used, enrichment for phosphopeptides using $TiO_2$ is often performed manually, which is labor-intensive and can lead to irreproducible results. To address the problems associated with offline enrichment and to improve the effectiveness of phosphopeptide detection, we developed an automated online enrichment system for phosphopeptide analysis. A standard protein mixture comprising BSA, fetuin, crystalline, ${\alpha}$-casein and ${\beta}$-casein, and ovalbumin was assessed using our new system. Our multidimensional system has four main parts: a sample pump, a 20-mm $TiO_2$-based column, a weak anion-exchange, and a strong cation-exchange (2:1 WAX:SCX) separation column with LC/MS. Phosphorylated peptides were successfully detected using the $TiO_2$-based online system with little interference from nonphosphorylated peptides. Our results confirmed that our online enrichment system is a simple and efficient method for detecting phosphorylated peptides.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3687-3691
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• 2011

Ion exchange experiments of molybdenum(VI) from strong HCl and $H_2SO_4$ solution have been done to investigate the existence of anionic complexes. The concentration of HCl and $H_2SO_4$was changed from 1 to 9 M. From the data on the complex formation of molybdenum in aqueous solution, a new distribution diagram of Mo(VI) was constructed in the pH range from zero to 10. AG 1 X-8, an anion exchange resin, and Diphonix, a cation exchange resin were used in the loading experiments. Ion exchange results indicate that anionic complexes of Mo(VI) begins to form from 3 M HCl and 1 M $H_2SO_4$ solution and the tendency to form anionic complexes is stronger in HCl than in $H_2SO_4$ solution. Our results can be utilized in the analysis of Mo(VI) in strong acid solution and in the design of a process to separate Mo(VI).

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.59-62
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• 2004

Hydraulic conductivity tests were conducted on a geosynthetic clay liner (GCL) for more than 2.5 yr using inorganic salt solutions to evaluate how the long-term hydraulic conductivity is affected by cation concentration and valence. Only small changes (i.e., $\leq$ 2X) in hydraulic conductivity (K) occurred during the test duration when the permeant solution was deionized (DI) water or 100 mM KCl and NaCl solutions. For weak CaCl$_2$ solutions ($\leq$ 20 mM), the hydraulic conductivities initially (< 0.2 yr) were comparable to the hydraulic conductivity obtained with DI water, but gradually increased by a factor of 2 to 13 over a period of nearly 2 yr. In contrast, the GCL permeated with strong CaCl$_2$ solutions ($\geq$ 50 mM) reached equilibrium nearly immediately, with a hydraulic conductivity approximately 2 orders of magnitude higher than the hydraulic conductivity to DI water.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.84-91
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• 2017

The concern over the use of melittin in honey bee venom due to its adverse reaction caused by allergens such as phospholipase A2 ($PLA_2$) and hyaluronidase (HYA) has been an obstacle towards its usage. We developed a novel single-step method for melittin purification and the removal of $PLA_2$ and HYA. This study explores the influence of pH, buffer compositions, salt concentration, and types of cation-exchange chromatography resins on the recovery of melittin and the removal of both HYA and $PLA_2$. Melittin was readily purified with a strong cation-exchange resin at pH 6.0 with sodium phosphate buffer. It resulted in a recovery yield of melittin up to 93% (5.87 mg from a total of 6.32 mg of initial melittin in crude bee venom), which is higher than any previously reported studies on melittin purification. $PLA_2$ (99%) and HYA (96%) were also successfully removed. Our study generates a single-step purification method for melittin with a high removal rate of $PLA_2$ and HYA, enabling melittin to be fully utilized for its therapeutic purposes.