• Economic and Environmental Geology
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• v.31 no.1
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• pp.11-20
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• 1998

The effects of the major cations ($Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$), complex-forming anions ($SO_4{^{2-}}$, $HCO_3{^-}$), and solution pH on the adsorption of $^{137}Cs$ and $^{90}Sr$ by kaolinite in groundwater chemistry were investigated. Three-dimensional Kd modelling designed by a statistical method was attempted to compare the relative effect among hydrated radii, charge and concentration of competing cations on the adsorption of Cs and Sr. The modelling results indicate that the hydrated radii of competing cations is the most important factor, and then their charges and concentrations are also important factors in order. The property of zeta potential of kaolinite particles was discussed in terms of the amphoteric reactions of a kaolinite surface affecting the adsorption of Cs and Sr. The ionic strength of competing cations on the adsorption of Cs and Sr exerts a greater effect than the solution pH. The sorption behaviour of Sr on kaolinite is also highly dependent on the concentration of bicarbonate. The speciation of Sr and the saturation state of a secondary phase were thermodynamically calculated by a computer program, WATEQ4F. This indicates that the change in solution pH with the concentration of bicarbonate and the precipitation of a strontianite ($SrCO_3$) are major factors controlling Sr adsorption behaviour in the presence of bicarbonate ion.

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.59-68
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• 2004

Three crystal structures of dehydrated partially $Co^{2+}-exchanged$ zeolite A treated with 0.6 Torr of K at $300^{\circ}C$ (for 12 hrs, 6 hrs, and 2 hrs) vapor have been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at 21(1)$^{\circ}C(a=12.181(1)\;{\AA},\;a=12.184(1)\;{\AA},\;and\;a=12.215(1)\;{\AA})\;respectively)$. Their structures were refined to the final error indices, R(weight) of 0.090 with 10 reflections, 0.091 with 82 reflections, and 0.090 with 80 reflections, respectively, for which $1>\sigma(I)$. In each structure, all four $Co^{2+}$ and four $Na^+$ ions to be reduced by K atoms. The cobalt and sodium atoms produced are no longer found in the zeolite. K species are found at five different crystallographic sites: three $K^+$ ions lie at the planes of 8-rings, filling that position, ca. 11.5 K^+$ ions lie on threefold axes, ca. 4.0 in the large cavity and ca. 4.0 in the sodalite cavity, and ca. 0.5 $K^+$ ion is found near a 4-ring. ca. three $K^0$ atoms are found deep into the large cavity on threefold axes. In these structures, crystallographic results show that cationic tetrahedral $K_4$ (and/or triangular $K_3$) clusters have formed in the sodalites of zeolite A. The $K_4$ and/or $K_3$ clusters coordinate trigonally to three oxygens of a six-oxygen ring. The partially reduced ions of these clusters interact primarily with oxygen atoms of the zeolite structure rather than with each other. ca. 14.5K species are found per unit cell, more than the twelve $K^+$ ions needed to balance the anionic charge of zeolite framework, indicating that sorption of $K^0$ has occurred. The three $K^0$ atoms in the large cavity are closely associated with three out of four $K^+$ ions in the large cavity to form $K_7^{4+}$ clusters. The $K_7^{4+}$ cluster not interacts primarily with framework oxygens.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.234-241
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• 1997

The effects of bulk densities(${\rho}_b$) on saturated hydraulic conductivity (Ksat) and solute elution patterns were investigated from five different bulk densities ranging from $1.1Mg/m^3$ to $1.5Mg/m^3$ with each increment of $0.1Mg/m^3$. The hydraulic conductivities observed were divided into two stages: (1) a linearly decrease with increase in bulk density up to $1.4Mg/m^3$, (2) a steady state where the bulk density is greater than $1.4Mg/m^3$. Using the saturated hydraulic conductivity at the steady state, we figured out the equation describing the correlation between bulk densities(${\rho}_b$) and saturated hydraulic conductivity(Ksat) as follows: $Ksat=-19.2({\rho}_b{^2})+6{\rho}_b+15.5$, (r=0.985). Electrical conductivity(EC) measured from the leachate of the soil column showed that EC at the same pore volume were decreased with an increase in the bulk density from $1.2g/cm^3$, $1.5g/cm^3$, as shown in the time taken to collect the same pore volume at each respective bulk density. The maximum relative concentrations (C/Co=1) from the breakthrough curves for the anions of $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$, which are weakly adsorbed on the soil particles, moved to the right of the graph, while a distinctive retardation occurs at the bulk density between $1.3Mg/m^3$ and $1.4Mg/m^3$. The time taken to recover about 90% of indigenous sulphate was approximately twice as those of chloride and nitrate, resulting in slightly stronger adsorption characteristics for sorption sites on the soil surface. Thus, we can conclude that the salt accumulation in green house soil might be significantly influenced by it's bulk density at the soil depth, as well as the adsorption capacity of ions for the sorption sites in soils.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.1
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• pp.6-12
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• 1999

This study was conducted to investigate the application of edible films to Raymyun soup packaging. The sorption isotherm curve and BET monolayer moisture content of Raymyun soup were estimated as a basic experiment. Also, the mechanical properties, water vapor permeability, and solubility of the films were investigated. Methylcellulose, sodium caseinate, and K-carrageenan films were used as edible films and glycerol and polyethylene glycol(MW 400) were used as plasticizers. In case tensile strength, methylcellulose films was 68.56 MPa and sodium caseinate film was 7.11 MPa. The elongations of sodium caseinate, methylcellulose, and K-carrageenan film were 115.41%, 23.79% and 0.60%, respectively. The water vapor permeabilties values of methylcellulose, sodium caseinate, and K-carrageenan film between 50% and 70% RH were $0.25-0.38ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa,\;0.62-0.84ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa\;and\;0.31-0.55ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa$, respectively. For the solubility of films, sodium caseinate film showed the highest solubility and methylcellulose film showed the lowest solubility.

• Journal of Environmental Impact Assessment
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• v.29 no.5
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• pp.350-362
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• 2020

In this study, nano Fe°-impregnated biochar (INPBC) was prepared using pruning residues and one-pot synthetic method and evaluated its performance as an amendment agent for the stabilization of arsenic-contaminated soil. For the preparation of INPBC, the mixture of pruning residue and Fe (III) solution was heated to 220℃ for 3hr in a teflon-sealed autoclave followed by calcination at 600℃ under N₂ atmosphere for 1hr. As-prepared INPBC was characterized using FT-IR, XRD, BET, SEM. For the stabilization test of as-prepared INPBC, As-contaminated soils (Soil-E and Soil-S) sampled from agricultural sites located respectively near E-abandoned mine and S-abandoned mine in South Korea were mixed with different of dosage of INPBC and cultivated for 4 weeks. After treatment, TCLP and SPLP tests were conducted to determine the stabilization efficiency of As in soil and showed that the stabilization efficiency was increased with increasing the INPBC dosage and the concentration of As in SPLP extractant of Soil-E was lower than the drinking water standard level of Ministry of Environment of South Korea. The sequential fractionation of As in the stabilized soils indicated that the fractions of As in the 1st and 2nd stages that correspond liable and known as bioavailable fraction were decreased and the fractions of As in 3rd and 4th stages that correspond relatively non-liable fraction were increased. Such a stabilization of As shows that the abundant nano Fe° on the surface of INPBC mixed with As-contaminated soils played the co-precipitation of As leaching from soil by surface complexation with iron. The results of this study may imply that INPBC as a promising amendments for the stabilization of As-contaminated soil play an important role.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.76-90
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• 2018

To determine the distribution of mercury (Hg) in the coastal surface sediments around the Korean peninsula, the baseline concentration of Hg was estimated, the extent of contamination was assessed, and the factors controlling the distribution were discussed. The concentrations of Hg in surface sediments were significantly high in Jinhae-Masan Bay in the South Sea, Ulsan-Onsan Bay and Yeongil Bay in the East Sea, but Hg in other sediments showed a similar distribution to Cs and relatively very low concentration between 0.21 and $39.5{\mu}g/kg$ ($13.6{\pm}7.80{\mu}g/kg$). Compared to the sediment quality guidelines in Korea, 8 % of the surface sediments (n=282) analyzed in this study exceeded the values of the threshold effects level (TEL), and six sediments collected around Onsan Port were higher than the value of the probable effects level (PEL). The contamination levels of Hg were assessed by the enrichment factors using the baseline concentration (2.06Cs+1.75) based on the residual analysis from the linear regression line for Cs, and further, factors controlling the distribution of Hg were discussed by the comparison with geochemical substances depending upon the Hg enrichment level. Hg concentrations were correlated well with Cs concentration in the range of less than 1.69 of EF implying grain size control, while in the range of 1.69 and 4.03 Hg concentrations were correlated well with Fe oxyhyroxide and organic carbon contents, which indicates Hg was enriched by superior sorption capability. On the meanwhile, samples with higher EFs (4.03 to 74.9) showed fairly positive correlations with other metals (Cu, Zn, Pb) rather than geochemical substances. For samples in Youngil Bay and Ulsan-Onsan Bay (n=30), Hg concentrations were correlated only with other metals rather than geochemical substances implying simultaneous supply of metal particles from metal refineries. But samples at Gosung, Sokcho and Uljin coast were correlated well with organic carbon even though they had high EFs. In addition, samples in Jinhae-Masan Bay with high contents of S were enriched by relatively high sulfide formation.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.42-51
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• 2004

Peat humin(p-Humin), humic acid(p-HA) and fulvic acid(p-FA) were isolated from Canadian Sphagnum peat moss by dissolution in 0.1M NaOH followed by acid precipitation. After purification cycles, they are characterized for their elemental compositions and, acid/base properties. Functionalities and carbon structures of the humic fractions were also characterized using FT-IR and solid state $^{13}C$-NMR spectroscopy. Those results are compared with one another and with soil humic substances from literatures. Main purpose of this study was to present a chemical and spectroscopic characterization data of humic substance from peat moss needed to evaluate its environmental applicability. The relative proportions of the p-Humin, p-HA and p-FA in the peat moss was $76\%,\;18\%,\;and\;3\%$, respectively, based on the total organic matter content ($957{\pm}32\;g/kg$). Elemental composition of p-Humin were found to be $C_{1.00}H_{1.52}O_{0.79}N_{0.01}$ and had higher H/C and (N+O)/C ratio compared to those of p-HA($C_{1.00}H_{1.09}O_{0.51}N_{0.02}$) and p-FA($C_{1.00}H_{1.08}O_{0.65}N_{0.01}$). Based on the analysis of pH titration data, there are two different types of acidic functional groups in the peat moss and its humic fractions and their proton exchange capacities(PEC, meq/g) were in the order p-FA(4.91) >p-HA(4.09) >p-Humin(2.38). IR spectroscopic results showed that the functionalities of the peat moss humic molecules are similar to those of soil humic substances, and carboxylic acid(-COOH) is main function group providing metal binding sites for Cd(II) sorption. Spectral features obtained from $^{13}C$-NMR indicated that peat moss humic molecules have rather lower degree of humification, and that important structural differences exist between p-Humin and soluble humic fractions(p-HA and p-FA).