• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.172-176
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• 2006

Fe(III)-Coated Star Fish (ICSF) was prepared by reaction of calcined Star Fish (SF) with Fe(III) solution at an elevated temperature. To investigate the stability of ICSF at acidic condition, dissolution of Fe was studied at pH 2 as a function of time. Extracted iron was negligible over the entire reaction time. This stability test suggests the applicability of ICSF in the treatment of wastewater even at low pH. Adsorption capacity of Cu(II) onto SF and ICSF was investigated in a batch and a column test. In the pH-edge adsorption, adsorption of copper onto SF and ICSF was quite similar over the entire pH range due to the presence of an important amount of Fe in SF itself. From the adsorption isotherm obtained with variation of the concentration of Cu(II), ICSF showed 1.6 times greater adsorption capacity than SF. Also, ICSF showed a greater removal capacity of Cu(II) in the column test.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.61-69
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• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.4
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• pp.29-42
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• 1986

This study is an experimental research on the adsorption capacity and the adsorption system utilizing Discarded Automotive Tires(DAT) and Powdered or Granular Activated Carbon(PAC or GAC) for the removal of heavy metals, Ag(I), Cd(II), Cu(II), Zn(II). Batch shaking test was conducted to determine the adsorption capacity of DA T and PAC in removing the heavy metals from aqueous wastes; and laboratory-scale column experiment was performed to present design factors affecting the optimum design of adsorption column with DAT and GAC, through the concept of Bed Deph/Service Time(BDST). As results, DAT has been proven to be a good adsorbent will its adsorption capacity not falling behind PAC or GAC. Factors affecting heavy metals removals were amount of adsorbents, initial concentrations, pH and so on. BDST equations were compared with values presented by the breakthrough data from adsorption system.

• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.21-29
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• 2015

BACKGROUND: Heavy metal adsorptionnot only depends on biochar characteristics but also on the nature of the metals involved and on their competitive behavior for biochar adsorption sites. The goal of this study was to investigate the competitive absorption characteristics of Cu and Cd in mono-metal and binary-metal forms by biochar derived from Phragmites communis. METHODS AND RESULTS: Batch and column experiments were conducted to evaluate the competitive adsorption characteristics of the biocharfor Cu and Cd. In the batch experiments, the maximum adsorption capacity of Cd(63 mg/g) by biochar was higher than that for Cu (55 mg/g) in the mono-metal adsorption isotherm. On the other hand, the maximum Cu adsorption capacity (40 mg/g) by biochar was higher than that for Cd(25 mg/g) in the binary-metal adsorption isotherm. Cu was the most retained cations. Cd could be easily exchanged and substituted by Cu. The amounts of adsorbed metals in the column experiments were in the order of Cd (121 mg/g) > Cu (96 mg/g) in mono-metal conditions, and Cu (72 mg/g) > Cd (29 mg/g) in binary-metal conditions. CONCLUSION: Overall, the results demonstrated that competitive adsorption among metals increased the mobility of these metals. Particularly, Cd in binary-metal conditions lost its adsorption capacity most significantly.

• Environmental Engineering Research
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• v.13 no.2
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• pp.79-84
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• 2008

Adsorption of heavy metals by sawdust was investigated to evaluate the effectiveness of using sawdust to remove heavy metals from aqueous solutions. Kinetic and isotherm studies were carried out by considering the effects of initial concentration and pH. The adsorption isotherms of heavy metals fitted the Langmuir or Freundlich model reasonably well. The adsorption capacity of metal was in the order $Pb^{2+}$ > $Cu^{2+}$ > $Zn^{2+}$. A high concentration of co-existing ions such as $Ca^{2+}$ and $Mg^{2+}$ depressed the adsorption of heavy metal. Adsorption data showed that metal adsorption on sawdust follows a pseudo-second-order reaction. Kinetic studies also indicated that both surface adsorption and intraparticle diffusion were involved in metal adsorption on sawdust. Column studies prove that sawdust could be effective biosorbent for the removal of heavy metals from aqueous phase.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.643-647
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• 2004

Natural antimicrobial substance from peanut (Arachis hypogaea) shells was isolated and structurally elucidated. Peanut shells were extracted with methanol (MeOH) and concentrated in vacuo, MeOH extract was solvent-fractionated with ethyl acetate (EtOAc) and various buffer to obtain EtOAc acidic, neutral, and phenolic fractions. EtOAc neutral fraction, which showed antimicrobial activity, was purified through silica gel adsorption column, Sephadex LH-20 column, ODS column, and high performance liquid chromatographies, and its active substance was isolated and identified as pratensein (3',5,7-trihydroxy-4'-methoxyisoflavone) by spectroscopic methods of proton-nuclear magnetic resonance, mass spectrometry, and nuclear overhauser enhancement spectroscopy.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1386-1391
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• 1999

The methanol extract of Gardenia jasminoides Ellis showed antimicrobial activity against bacteria and yeasts. The extract was successively purified with solvent fractionation, silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, octadecylsilane column chromatography. The purified active substance was isolated by high performance liquid chromatography. The isolated compound was 3,4-dihydroxybenzoic acid which was determined by mass spectrometer, gas chromatograph-mass spectrometer, $^{1}H-nuclear$ magnetic resonance, $^{13}C-nuclear$ magnetic resonance and two-dimensional nuclear magnetic resonance. The content of 3,4-dihydroxybenzoic acid was $32.7\;{\mu}g/g$ in dried fruits of Gardenia jasminoides Ellis.

• Advances in environmental research
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• v.4 no.2
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• pp.135-142
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• 2015

In this study, we evaluated the adsorption/desorption of uranium (U) in pure soil environment using continuous column reactor. We additionally investigated the adsorption/desorption mechanism of U on vivianite surface in molecular scale using quantum calculation. We observed that below $0.1{\mu}M$ of U was detected after 20 d from U injection ($1{\mu}M$) in adsorption test. However, all of absorbed U was detached from vivianite surface in 24 h by injection of CARB solution ($1.44{\times}10^{-2}M\;NaHCO_3$ and $2.8{\times}10^{-3}M\;Na_2CO_3$). Based on exchange energy calculation, we found that $UO_2(CO_3)_2{^{2-}}$ and $UO_2(CO_3)_3{^{4-}}$ species have higher repulsive energy than $UO_2(OH)_2$ species. The results obtained from this study could be applied to predict the behavior of uranium in contaminated and remediation sites.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3017-3026
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• 2022

The ¹³¹Cs radioisotope with a short half-life time and high average radiation energy can treat the cancer effectively in prostate brachytherapy. The typical ¹³¹Cs production processes have a separation step of the cesium from ¹³¹Ba to obtain a high specific radioactivity. Herein, we suggested a novel ¹³¹Cs separation method based on the Ba²⁺ adsorption of alginate beads. It is necessary to reduce the affinity of alginate beads to cesium ions for a high production yield. The carboxyl group of the alginate beads was replaced by a sulfonate group to reduce the cesium affinity while reinforcing their affinity to barium ions. The modified beads exhibited superior Ba²⁺ adsorption performances to native beads. In the fixed-bed column tests, the saturation time and adsorption capacity could be estimated with the Yoon-Nelson model in various injection flow rates and initial concentrations. In terms of the Cs elution, the modified alginate showed better performance (i.e., an elution over 88%) than the native alginate (i.e., an elution below 10%), indicating that the functional group modification was effective in reducing the affinity to cesium ions. Therefore, the separation of cesium from the barium using the modified alginate is expected to be an additional option to produce ¹³¹Cs.

• Journal of Korean Society on Water Environment
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• v.38 no.1
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• pp.10-18
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• 2022

This study was conducted to investigate the effect of soil and groundwater environment changed by wildfire on cesium adsorption and transport. Soil samples (A, B) used in the study were collected from Gangwon-do, where wildfires frequently occur, and the adsorption and transport of cesium in the samples were evaluated through batch and column experiments. As a result of the batch adsorption experiments with various concentrations of cesium (C_W ≈ 10~10⁵ ㎍/L), the adsorption distribution coefficient (K_d) of cesium was higher in sample A for all observed concentrations. It means that the adsorption capacity of sample A was higher to that of sample B, which was also confirmed through the parameters of adsorption isotherm models (Freundlich and Langmuir model) applied to the experimental results. The fixed bed column experiments simulated the actual soil and groundwater environment, and they showed that cesium was retarded approximately 43 and 27 times than a nonreactive tracer in sample A and B, respectively. In particular, a significant retardation occurred in the sample A. Although sample A contains little clays, total organic carbon (TOC) contents were 3 times greater than sample B. These results imply that particulate organic matter caused by wildfire might influence the adsorption and transport of cesium in the organic matter-rich soil and groundwater environment.