• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.1
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• pp.39-49
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• 2021

The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs's specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 ㎛) and extracted from near South Korea's Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample's cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl's ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.43-46
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• 2000

$H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$￣ to $NO_2$￣ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$￣ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.112-117
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• 2017

Ion exchange fiber, PADD was synthesized by the reaction between PAN based acrylic fiber and DETA with $AlCl_3{\cdot}6H_2O$, and was analyzed by FT-IR and SEM to investigate its characteristics. The experimental results of Cr(VI) removal by PADD were better fitted with Langmuir adsorption isotherm, and the maximum uptake value ($Q_{max}$) was calculated to be 6.93 mmol/g. The kinetic data can be well described by Lagergen pseudo-second order rate model. The Cr(VI) adsorption capacity of PADD was 4.11 mmol/g at pH 2, which shows the effect of pH changes on the removal of Cr(VI). The adsorption selectivity of Cr(VI) was higher than phosphate and As(V). Total ion exchange capacity of PADD was 4.70 mmol/g, which was measured by acid-base back titration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.69-73
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• 2004

Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.253-260
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• 2005

Salt accumulation in the plastic film house soils under continuous cultivation condition causes problems such as salt damages to plants, nitrate accumulation in vegetables, groundwater contamination, etc. due to excess application of fertilizers. Objective of this research was to find an optimum adsorbent to reduce salt concentration in the soil solution of plastic film house soils, where crop injuries have been observed due to the salt accumulation. The soils were significantly high in available P $(1,431{\sim}6,516mg\;kg^{-1}),\;NO_3-N\;(117.60{\sim}395.73mg\;kg^{-1})$, exchangeable Ca $(4.06{\sim}11.07\;cmol_c\;kg^{-1})$ and Mg $(2.59{\sim}18.76\;cmol_c\;kg^{-1})$, as compared to those of the average upland soils in Korea. Soils were treated with each of adsorbent such as ion-exchange resin, zeolite, rice bran, etc. at 2% level and prepared into saturated-paste samples. After equilibrium, soil solution was vacuum-extracted from the soil and measured for changes of the pH, EC, and concentrations of $Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+,\;{NH_4}^+,\;{PO_4}^{3-}\;and\;{NO_3}^-$. Rice bran effectively removed ${PO_4}^{3-}\;and\;{NO_3}^-$ in the soil solution up to 100%. Efficiency was decreased in the orders of rice bran > ion-exchange resin > zeolite. Removal efficiencies of zeolite and ion-exchange resin for $Ca^{2+}$ were ranged from 1 to 65% and from 7 to 61%, respectively. Ion-exchange resin was also effective for removing $Mg^{2+},\;K^+,\;Na^+,\;and\;{NH_4}^+$. Overall results demonstrated that rice bran and ion-exchange resin could be applicable for salt accumulated soil to remove the respective anion and cation.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.427-434
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• 1998

An alkaline protease was 4-fold purified, yielding 2.3% of recovery by ammonium sulfate precipitation, CM-cellulose column chromatography and Sephadex G-100 column chromatography. The purified enzyme was estimated to be monomeric with molecular weight of about 62,000 from polyacrylamide gel eletrophoresis (PAGE) and sodiumdodecylsulfate polyacrylamide gel electrophoresis (SDS-FAGE). The optimal pH and temperature of the alkaline pretense activity were 11.0 and 50$^{\circ}C$, respectively, exhibiting high stability at pH value from 6.0 to 11.0 at 50$^{\circ}C$ for 30 minute. The alkaline pretense was activated by MnSO$_4$, CaCl$_2$, and was inhibited by CuSO$_4$, ZnSO$_4$, HgCl$_2$, EDTA and EGTA. Also, the enzyme was found to be a metaloenzyme requiring Mn$\^$2+/ as cofactor. The NH$_2$-terminal amino acid of alkaline protease was alanine. The Km and Vmax values of this enzyme for casein was 4.0 mg/$m\ell$ and 5,500 unit/$m\ell$, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.527-534
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• 2006

The purpose of this study is the development of more effective filter-type polymer adsorbent for removal of anionic pollutants from wastewater. In order to synthesize the polymer adsorbent that possesses anionic exchangeable function, carboxyl(-COOH) group of PP-g-AA nonwoven fabric was converted into amine($-NH_2$) group by the chemical modification using diethylene triamine(DETA). FT-IR data indicate that amine group was introduced into PP-g-AA through amidation of grafted acrylic acid by reaction with DETA. The degree of amination increased with increase in the reaction time and temperature of the chemical modification process, and was significantly improved by the pre-swelling treatment of PP-g-AA with solvent and addition of metal chlorides as a catalyst in following order as $NH_4OH>MeOH{\geq}HCl{\geq}H_2O\;and\;AlCl_3>FeCl_3{\geq}SnCl_2{\gg}ZnCl_2{\geq}FeCl_2$, respectively. However, the addition of catalyst limited the reusability of DETA, hence was less useful from the viewpoint of cost effectiveness and waste management. The anion exchange capacity of the aminated PP-g-AA(PP-g-AA-Am) increased with increase in the degree of amination, but it reached maximum value at the degree of amination as about $50{\sim}60%$. The anion exchange capacity of PP-g-AA-Am was higher than those of commercial anion resins.

• YAKHAK HOEJI
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• v.31 no.2
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• pp.52-59
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• 1987

The result of the screening of lectins on 28 species of marine shell fishes(mollusks) showed that 10 species (Tapes philippinarum, Cyclosunetta menstrualis, Neptunea arthritica cumingii, Omphalius pfeifferi carpenteri, Chlorostoma argyrostoma turbinatum, Chiorostoma argyrostoma lischkei, Semisulcosira corea, Neptunea polycosta, Babylonica japonica, Noverita didyma) were present hemagglutinating properties to human A, B, and O group, and animal blood erythrocytes. A new lectin from Tapes philippinarum. was isolated and partially characterized. The lectin was purified by (NH$_4$)$_2$SO$_4$ precipitation and ion exchange chromatography on DE 53 column. Six fractions were obtained from DE 53 column by salt gradient elution but only 0.3M, and 0.4M NaCl fraction had strong lectin activity. On its 0.3M NaCl fraction, purity was identified by polyacrylamide gel electrophoresis. This lectin was inhibited by N-acetyl-D-galactosamine. It seems that two kinds of lectin react as antigen by immunochemical studies.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.751-758
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• 2004

The NCS(Non-Cariogenicity Sugar) from Bacillus sp. S-1013 was purified by cold acetone and methanol precipitation, and DEAE-cellulose ion-exchange and Sephadex G-100 column chromatographies, to yield an amorphous yellow syrup. The melting point and $[\alpha]_D^{20}$ were 155-$157^{\circ}C$ and +53, respectively. Instrumental analyses such as FT-IR, $^1H-NMR, and ^{13}C-NMR$ showed that the NCS contained an O-H group, C-H, C=O, $NH_2$, anomeric carbon, anomeric proton, N-acetylgalactose, fucose, and neuramic acid, thus, the NCS was determined to be a trisaccharide of Fuc($1\longrightarrow4$)GalNAc($2\longrightarrow6$) NeuAc.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1255-1263
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• 2008

The efficiency of PP-g-AA and PP-g-St nonwoven fabric synthesized by photoinduced polymerization as an adsorbent for removal $NH_3-N$ from waste water was evaluated. The results evidently indicate that the adsorption capacities of $NH_3-N$ onto PP-g-AA nonwoven fabric were extremely superior to those onto sulfonated PP-g-St nonwoven fabric, PK and zeolite. PP-g-AA nonwoven fabric showed the maximum adsorption capacity of $NH_3-N$ at the degree of grafting of 80 wt.%. The adsorption behaviour of $NH_3-N$ onto PP-g-AA and sulfonated PP-g-St nonwoven fabric was controlled by an ion exchange reaction, and tended to be similar to both trends of Langmiur and Freundlish isotherm. Futhermore, PP-g-AA non-woven fabric could be regenerated more than 5 times by a simple washing with 0.1N HCl with no decrease of adsorption capacity and no degradation of physical properties. Also sulfonated PP-g-St nonwoven fabric could be regenerated by washing with 0.1N ${H_2}{O_4}$. However, their regeneration efficiency was significantly low because grafting layer acted as functional radical for adsorption was continuously desquamated in the adsorption or regeneration processes, which resulted in decrease of adsorption capacity and weight of adsorbent. All results obtained from this study indicate that the $NH_3-N$ removal capacity of PP-g-AA non-woven fabric was extremely superior to those of PP-g-St non-woven fabric, PK and zeolite.