• 한국환경과학회지
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• 제20권5호
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• pp.667-672
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• 2011

The purpose of this work is to present the experiment results by a dynamic adsorption of water vapor on pelletized zeolites (ADZ300, ADZ400, and ADZ500) in fixed bed. The breakthrough curves of water vapor with several different concentrations and temperature in the range of 25~45 $^{\circ}C$ on zeolite bed were investigated. In the same conditions, the breakthrough time on ADZ400 and ADZ500 were little longer than ADZ300, and the equilibrium adsorption capacity on ADZ500 was highest. The higher the concentration of water vapor was, the faster the breakthrough time was, and the slope of breakthrough curves showed a tendency to increase. The faster the flow rate of water vapor was, the faster the breakthrough time was relatively, but variations between flow rate and breakthrough time did not have a proportional relationship. The breakthrough curve maintained constant gradient in spite of variation of flow rate in the same concentration. The temperature rise in zeolite bed by adsorption heat was occurred in the early stage of adsorption. After water molecule layers were formed on the surface of zeolite, the temperature was slowly cooled by water vapors continuously flowed in as constant temperature. The greater the concentration of water vapor and adsorption temperature were, the temperature difference in zeolite bed was increased.

• 한국환경과학회지
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• 제23권3호
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• pp.379-386
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• 2014

Adsorption and biodegradation performance of tetracycline antibiotic compounds such as ttetracycline (TC), oxytetracycline (OTC), minocycline (MNC), chlortetracycline (CTC), doxycycline (DXC), meclocycline (MCC), demeclocycline (DMC) on granular activated carbon (GAC) and anthracite-biofilter were evaluated in this study. Removal efficiency of seven tetracycline antibiotic compounds showed 54%~97% by GAC adsorption process (EBCT: 5~30 min). The orders of removal efficiency by GAC adsorption were tetracycline, demeclocycline, oxytetracycline, chlortetracycline, doxytetracycline, meclocycline and minocycline. Removal efficiencies of seven tetracycline antibiotic compounds showed 1%~61% by anthracite biofiltration process (EBCT: 5~30 min). The highest biodegradable tetracycline antibiotic compound was minocycline, and the worst biodegradable tetracycline antibiotic compounds were oxytetracycline and demeclocycline.

• 상하수도학회지
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• 제21권3호
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• pp.349-357
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• 2007

Reports of endocrine disrupting compounds (EDCs), pharmaceutically active compounds (PhACs), and personal care products (PCPs) have raised substantial concern in important potable drinking water quality issues. Our study investigates the removal of EDCs, PhACs, and PCPs of 10 compounds having different physico-chemical properties (e.g., molecular weight, and octanol-water partition coefficient ($K_{OW}$)) by nanofiltration (NF) membranes. The rejection of micropollutants by NF membranes ranged from 93.9% to 99.9% depending on solute characteristics. A batch adsorption experiments indicated that adsorption is an important mechanism for transport/removal of relatively hydrophobic compounds, and is related to the octanol-water partition coefficient values. The transport phenomenon associated with adsorption may also depend on solution water chemistry such as pH and ionic strength influencing the pKa value of compounds. In addition, it was visually seen that the retention was somewhat higher for the larger compounds based on their molecular weight. These results suggest that the NF membrane retains many organic compounds due to both hydrophobic adsorption and size exclusion mechanisms.

• Advances in environmental research
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• 제7권1호
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• pp.53-71
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• 2018

Waste glass disposal causes environmental problems in the cities. To find a suitable green environmental solution for this problem low cost adsorbent in this study was prepared from waste glass. An effective new green adsorbent was synthesized by hydrothermal treatment of waste glass (WG), followed by acidic activation of its surface by HCl (WGP). The prepared adsorbent was characterized by scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), and BET surface measurement. The developed adsorbent was used for the removal of heavy metals (Cd, Cu, Fe, Pb and Zn) from well water. Batch experiments were conducted to test the ability of the prepared adsorbent for the removal of Cd, Cu, Fe, Pb and Zn from well water. The experiments of the heavy metals adsorption by adsorbent (WGP) were performed at different metal ion concentrations, solution pH, adsorbent dosage and contact time. The Langmuir and Freundlich adsorption isotherms and kinetic models were used to verify the adsorption performance. The results indicated high removal efficiencies (99-100%) for all the studied heavy metals at pH 7 at constant contact time of 2 h. The data obtained from adsorption isotherms of metal ions at different time fitted well to linear form of the Langmuir sorption equation, and pseudo-second-order kinetic model. Application of the resulted conditions on well water demonstrated that the modified waste glass adsorbent successfully adsorbed heavy metals (Cd, Cu, Fe, Pb and Zn) from well water.

• Carbon letters
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• 제7권4호
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• pp.249-258
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• 2006

Treatment of water hyacinth with sulphuric acid produces carbonaceous materials that have been used to remove Cu(II) and Cd (II) ions from aqueous solutions. Untreated water hyacinth was also used for the subject of comparison. The textural properties of the carbonaceous materials were determined from nitrogen adsorption at 77 K. The optimum pH for the sorption of Cu (II) and Cd (II) ions on the investigated sorbents was determined. Dynamic adsorption measurements have been taken at 298 K whereas equilibrium measurements were carried out at 298, 313 and 323 K. The adsorption of nitrogen at 77 K on the untreated sample was too low and the surface areas of the treated samples 2, 3 and 4 were found between $70-208\;m^2/g$. The total pore volumes of these samples which were determined for the carbonaceous materials investigated were found to be 0.076-0.140 ml/g. The kinetic adsorption data of Cu (II) and Cd(II) were applicable to both pseudo - first and pseudo-second order but fit more the latter order. The equilibrium adsorption data were found to fit Freundlich and Langmiur equations. The values of DG, DH and DS are all negative indicating the feasibility and the spontaneous nature of the sorption of Cu (II) and Cd (II) ions by the sorbents investigated.

• 한국물환경학회지
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• 제25권3호
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• pp.459-463
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• 2009

The adsorption features of malachite green onto activated carbon have been investigated for its treatment from aqueous solution. The influential factors were examined the initial concentration of malachite green, reaction temperature, and pH. Under experimental conditions, adsorption equilibrium of malachite green was attained within 2 hr after the adsorption started. The adsorption reaction of malachite green followed the pseudo-second order rate model, and the adsorption rate constants(k2) decreased with increasing initial concentrations of malachite green. Adsorption behavior of malachite green on activated carbon was found to follow the Freundlich model well in the initial adsorbate concentration range. With increase in temperature, the adsorbed amount of malachite green at equilibrium increased, which indicate that the adsorption reaction was endothermic reaction. Thermodynamic parameters for malachite green adsorption reaction were estimated at varying temperatures, and in the pH range of 2-10, adsorption of malachite green increased.

• 한국물환경학회지
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• 제22권3호
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• pp.498-503
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• 2006

Adsorption features of $Cd^{2+}$ on waste tire particles have been investigated for the purpose of enhanced wastes recycling along with the development of an economic process for wastewater treatment. The isoelectric point of waste tire particles was found to be ca. pH 7 and the adsorbed amount of $Cd^{2+}$ was increased with pH under experimental conditions. The variation of the adsorption behavior of $Cd^{2+}$ with pH was well explained by the change of the electrokinetic potential of waste tire particles according to the pH. Adsorption of $Cd^{2+}$ was observed to reach its equilibrium within 45 minutes after the adsorption started under experimental conditions and followed the Freundlich model well. Kinetic analysis showed that the adsorption reaction of $Cd^{2+}$ was second order and thermodynamic estimation substantiated the endothermic behavior of $Cd^{2+}$ adsorption. As the amount of adsorbent increased, more adsorption of $Cd^{2+}$ was accomplished and the adsorption capacity of adsorbent was found to be enhanced by its pre-treatment with NaOH. Also, the adsorption of adsorbate was promoted as the ionic strength of wastewater was increased.

• 한국물환경학회지
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• 제27권4호
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• pp.516-522
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• 2011

This study was performed to investigate the removal characteristics of phosphate by adsorption on olivine, which is generated as industrial by-products from quarry. The adsorption of phosphate on olivine was significantly achieved within 1 hour and equilibrated after 3 hours. The adsorption capacity of phosphate was enhanced with decreasing pH. The maximum adsorption capacity was observed to be 0.463 mg/g in the condition of pH 3. The $Ca^{2+}$ and $Mg^{2+}$ ion amount per adsorbent eluted from olivine was increased with decreasing pH. The precipitation test showed that phosphate in aqueous phase under the condition of pH 3 ~ 9 could be eliminated largely by adsorption on olivine, not precipitation. Freundlich adsorption model were successfully applied to describe the adsorption behavior of phosphate on olivine. The $q_m$ of Langmuir adsorption model were 1.3369 mg/g, 1.0544 mg/g, 1.0288 mg/g at pH 3, 6 and 9, respectively. The $K_F$ of Freundlich adsorption model were 0.4247 mg/g, 0.3399 mg/g, 0.2942 mg/g at pH 3, 6 and 9, respectively. The olivine showed high feasibility as a adsorbent for the removal of $PO_4$-P.

• Journal of the Korean Wood Science and Technology
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• 제24권3호
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• pp.51-56
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• 1996

The Bark lignin(alkali- and acid lignin), bark extractives(hot water-and $Na_2SO_3$ extractives) of Quercus acutissima and Pinus densiflora, and flavonoids were used to detect heavy metal adsorption. The adsorption ratio of heavy metals by lignin was assigned for 40 to 50%, but was not dependent on lignin kinds. However, in case of the addition of light metals such as $Ca^{++}$ and $Mg^{++}$ to lignin the adsorption ratio was increased by 20 to 40%, and $Pb^{++}$ was almost completely adsorbed. On hot water extractives, the adsorption ratio was very low because the substrate was water-soluble, so the substrate should be water-insoluble to adsorb the heavy metals. However, the adsorption ratios of $Cd^{++}$ and $Pb^{++}$ on $Na_2SO_3$ extractives were significantly increased, while those of $Zn^{++}$ and $Cu^{++}$, were similar to lignin. When four kinds of heavy metals were treated to $Na_2SO_3$ extractives together, more than 97% of $Pb^{++}$ and $Cu^{++}$ was adsorbed_ and $Zn^{++}$ was more adsorbed by 40%, and $Cd^{++}$ was not changed, comparing with the case that on kind of heavy metal was treated. There were differences between adsorption ratio of the kinds of flavonoids and heavy metals, and the adsorption ratio of heavy metals was assigned to 20 to 45% per 0.1g flavonoid.

• 약학회지
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• 제23권3_4호
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• pp.133-140
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• 1979

The adsorption of erythrosine in the aliphatic alcohols by antibiotics such as ampicillin anhydrous, ampicillin trihydrate, amoxicillin trihydrate, cephalexin monohydrate was studied. The adsorption isotherms were all described with Freudlich equation. From the various experimerts, it was found that the adsorption of erythrosine by antibiotics in the aliphatic alcohols was affected by the solubility of adsorbents. The adsoption in the mixture of aliphatic alcohols and water is related with the dielectric constant of mixed solvents. According to increase in the pH values of aqueous solution, the adsorption of erythrosine for antibiotics is decreased, but increased in the mixture of aliphatic alcohols and water. The adsorption of erythrosine in the suspension of antibiotics showed a correlation with the temperature. Colloidal silica which is used as stabilizer had a favorable effect on the adsorption of erythrosine in the suspension of antibiotics.