• Journal of Soil and Groundwater Environment
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• v.27 no.6
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• pp.11-21
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• 2022

Sorption of phenanthrene (PHE) and pyrene (PYR) in several sorbents, i.e., natural soil, BionSoil^®, Pahokee peat, vermicompost and Devonian Ohio Shale and a surfactant (hexadecyltrimethyl ammonium chloride)-modified montmorillonite (HDTMA-M) were investigated. Pyrene exhibited higher sorption tendency than phenanthrene, as predicted by its higher octanol to water partition coefficient (K_ow). Several sorption models: linear, Freundlich, solubility-normalized Freundlich model, and Polanyi-Manes model (PMM) were used to analyze sorption isotherms. Linear isotherms were observed for natural soil, BionSoil^®, Pahokee peat, vermicompost, while nonlinear Freundlich isotherms fitted for Ohio shale and HDTMA-M. The relationship between sorption model parameters, organic carbon content (f_oc), and elemental C/N ratio was studied. In the binary competitive sorption of phenanthrene and pyrene in natural soil, competition between the solutes caused reduction in the sorption of each solute compared with that in the single-solute system. The ideal adsorbed solution theory (IAST) coupled with the single-solute Freundlich model was not successful in describing the binary competitive sorption equilibria. This was due to the inherent nature of linear sorption of phenanthrene and pyrene in natural soil. The result indicates that the applicability of IAST for the prediction of binary competitive sorption is limited when the sorption isotherms are inherently linear.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.15-18
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• 2001

Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.83-89
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• 2014

The aim of this study is to investigate the sorption/ion exchange of radioactive nuclides such as $Cs^+$ and $Sr^{2+}$ by synthetic Na-micas. In order to prepare Na-micas, two natural micas (phlogopite and biotite) were used as precursor materials. XRD, SEM, and EDS analyses were used to examine material characterization of synthetic Na-micas. Analyses of materials revealed that Na-micas were successfully obtained from natrual micas by K removal treatment. On the other hand, single solute (Cs or Sr) and bi-solute (Cs/Sr) sorption experiments were carried out to determine sorption capacity of Na-micas for Cs and Sr under different pH and ionic strength conditions. Uptake of Cs and Sr by micas in bi-solute system was lower than in single-solute system. Additionally, Langmuir and Langmuir competitive models were applied to describe sorption isotherm of Na-micas. bi-solute system was well described by Langmuir competitive models. For the results obtained in this study, Na-micas could be promising sorbents to treat multi-radioactive species from water and groundwater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.302-305
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• 2002

Scoria is a bomb-sized, generally vesicular pyroclast that is red or black in color and light in weight. In this study, scoria from Cheju was examined for the use as a sorbent. It is composed of plagioclase, olivine, hornblende, pyroxene, and glass, with an average composition of 49.84% SiO$_2$, 14.07% A1$_2$O$_3$, End 9.14% Fe$_2$O$_3$. Studies on kinetic isotherm sorption of Zn(II) onto scoria under various parameters such as initial zinc concentration, particle size, and adsorbent/adsorbate ratio were carried out using an agitated batch. The results suggest that the smaller scoria size and the larger adsorbent/adsorbate ratio produce the higher degree of Zn(II) removal. More effective removal also appears at lower initial Zn concentration. The sorption behavior of Zn(II) onto scoria seems to be mainly controlled by cation exchange. Studies on equilibrium isotherm sorption of other heavy metals (Pb, Cu, Cd) onto scoria were also conducted and compared with those onto powdered activated carbon (PAC) and non-organic matter scoria (NOS), The results suggest that the Cheju scoria has the slightly higher sorption capability than PAC and NOS, and the order of the effective sorption onto scoria and PAC is Pb > Cu > Zn > Cd. The monometal sorption onto scoria is more stronger than the competitive sorption.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.19-22
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• 2001

The effects of pH on the sequential sorption/desorption of chlorinated phenols (2-chlorophenol, 2.4-dichlorophenol and 2,4,5-trichlorophenol) in HDTMA-montmorillonite were investigated by maintaining pH 4.85 or 9.15 in the sequential batch sorption and desorption experiments. The chlorinated phenols are hydrophobic ionizable orginic compounds; they can exist as either neutral (pH << pKa) or anionic (pH >> pKa) forms. Among the tested chlorinated phenols, 2,4,5-trichlorophenol showed the highest sorption affinity at pH 4.85 as expected by the $K_{ow}$ . Neutral speciation at pH 4.85 exhibited higher sorption affinity than anionic speciation at pH 9.15. Our results indicates that desorption of chlorinated phenols is strongly dependent on pH of the aqueous phase. Freundlich model was used to analyze the single-solute sorption/desorption results. The ideal adsorbed solution theory(IAST) was employed to predict the hi-solute sorption/desorption equilibria.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.253-254
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• 2018

• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.250-260
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• 1996

Observed results of the adsorption between two competing anions for the shared sorption sites represent that the adsorption phenomena may depends on the characteristics of anion and available sorption sites in a given conditions. In binary systems, adsorption of one species can significantly influence the fate of the other anion, resulting in control of the extent of solute-adsorbate distributions throughout soil profile. And the proton-donation mechanisms by organic anions having a carboxyl as a functional group can also influence the adsorption of inorganic anions onto the hydroxylated sites of Fe and Al oxides. However, study of competitive adsorption of specifically adsorbed anions illustrates some of difficulties which arise in interpretation of reactions at oxide/aqueous solution interfaces. At least two factors prevented a simple analysis of reactions. First, at any pH value the maximum amount of adsorbate taken up at the surface depends on the identity of the anion. Second, it was necessary to postulate the sorption sites where the anion can be adsorbed. Hence, anions having non-specific adsorption characteristics are less capable for sorption sites, compared to those of specific adsorption characteristics, even though competition complies both ordinary and electrostatic interactions for sorption sites. Therefore, competition among chemical species in soil matrix can be of major significance in determining the effective mobility of any reactive anions with sorption sites.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.5
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• pp.238-246
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• 2005

We conducted this investigation to observe competitive adsorption phenomena among the heavy metals onto the available sorption sites of soil particle surfaces in sandy clay loam and clay soil collected from Nonsan city, Chungnam and Yoosung, Daejeon in Korea, respectively. Polluted and contaminated soils can often contain more than one heavy metal species, resulting in competition for available sorption sites among heavy metals in soils due to complex competitive ion exchange and specific sorption mechanism. And the adsorption characteristics of the heavy metals were reported that the selectivity for the sorption sites was closely related with electropotential and electro negativity carried by the heavy metals. The heavy metals were treated as single, binary and ternary systems as bulk solution phase. Adsorption in multi-element system was different from single-element system as Cr, Pb and Cd. The adsorption isotherms showed the adsorption was increased with increasing equilibrium concentrations. For binary and ternary systems, the amount of adsorption at the same equilibrium concentration was influenced by the concentration of individual ionic species and valence carried by the respective heavy metal. Also we found that the adsorption isotherms of Cd and Pb selected in this experiment were closely related with electronegativity and ionic potential regardless number of heavy metals in solution, while the adsorption of Cr carried higher valance and lower electro negativity than Cd and Pb was higher than those of Cd and Pb, indicating that adsorption of Cr was influenced by ionic potential than by electronegativity. Therefore adsorption in multi-element system could be influenced by electronegativity and ionic potential and valance for the same valance metals and different valance, respectively. But it still needs further investigation with respect to ionic strength and activity in multi-element system to verify sorption characteristics and reaction processes of Cr, especially for ternary system in soils.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.99-106
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• 2019

Arsenic is among the heavy metals commonly found in aqueous environments. Iron oxide is known as an efficient adsorbent for the arsenic. A new synthetic method was applied to provide iron oxide giving a large specific surface area. The mixing method affects the formation of iron oxide. Ultrasonic waves assisted the formation of very fine iron oxide in an organic phase. The synthesized iron oxide is amorphous type with a high surface area of more than $181.3m^2/g$. Sorption capacity of the synthesized adsorbent was relatively very high for arsenic and varied depending on the oxidation state of arsenic: a higher capacity was obtained with As(V). Lower solution pH provided a higher sorption capacity for As(V). The competitive effect of co-exist anions such as chloride, nitrate, and sulfate was minimal in sorption capacity of the iron oxide for arsenic.