• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1146-1152
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• 2005

Graft copolymers were synthesized from methylcellulose(MC) and acrylic acid(AA) with active carboxyl groups in the presence of potassium persulfate($K_2S_2O_8$) initiator to enhance adsorption capacity of toxic heavy metal such as $Pb^{2+}$ and $Cu^{2+}$ from wastewater. The resulting grafted copolymers(MC-g-AA/PAA) were mixture of the graft copolymers from MC and AA(MC-g-AA) and polyacrylic acid homopolymers(PAA). The degree of palling was increased with rising concentration of monomer and initiator under the reaction conditions at $60^{\circ}C$, 3 hrs. The water insoluble property of MC-g-AA showed more than 19.7% degree of grafting. So that it could be an adsorbent of heavy metals. Adsorption characteristics of the MC-g-AA were evaluated depending on the degree of grading, pH of wastewater, adsorption time, dosage of MC-g-AA and concentration of heavy metals in the different conditions. Degree of grafting, and initial concentration of heavy metal ions increased, the adsorption amount of $Pb^{2+}$ and $Cu^{2+}$ increased, but added MC-g-AA increased, the adsorption amount per unit weight of $Pb^{2+}$ and $Cu^{2+}$ decreased. The MC-g-AA showed the high $Pb^{2+}$ and $Cu^{2+}$ adsorption amount in the range pH $4{\sim}6$. Also all of $Pb^{2+}$ and $Cu^{2+}$ ions reached in adsorption equilibrium in neighborhood 4 hours. The adsorption of heavy metals described by Freundlich isotherm, it was determined the value of l/n of $Pb^{2+}$ and $Cu^{2+}$ that 0.4294 and 0.3453, respectively.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.798-806
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• 2017

A activated carbon (WCAC, waste citrus activated carbon) prepared from an agricultural waste citrus peel material generated in Jeju was utilized for the removal of dimetridazole (DMZ) antibiotics in aqueous solution. The adsorption of DMZ on WCAC was investigated with the change of various parameters such as contact time, dosage of WCAC, particle size of WCAC, temperature, pH, and DMZ concentration. The DMZ adsorption capacity increased with increasing temperature and decreasing particle size. Also it was decreased at less than pH 4 but sustained almost constantly at pH 4 or greater. Isotherm parameters were determined from the Langmuir, Freundlich, Redlich-Peterson and Duinin-Radushkevich (D-R) isotherm models. The isotherm data were best described by the Redlich-Peterson isotherm model. And the adsorption kinetics can be successfully fitted to the pseudo-second-order kinetic model. The results of the intra-particle diffusion model suggested that film diffusion and intra-particle diffusion were occurred simultaneously during the adsorption process. Meanwhile, the thermodynamic parameters indicated that the adsorption reaction of DMZ on WCAC was an endothermic and spontaneous process. The experimental results showed that WCAC is a promising and cheap adsorbent for the removal of DMZ antibiotics.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.45-49
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• 2006

The removal of copper ion from aqueous solution by adsorption with bone char that made from spent pig bone has been studied. This paper was studied the effects of bone char dosage and pH. The optimal results show that bone char adsorbs about 96.5 percent of copper ion in aqueous solution containing 50 mg/L as initial concentration at pH 5.0 when the bone char of 5g/L is used for 30 hours. Increase in the initial pH of the copper solution resulted in an increase in the copper ion uptake per weight of the sorbent Freundlich isotherm model was found to be applicable for the experimental data of $Cu^{2+}$.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.609-615
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• 2015

This study was carried out for characterization of MIO synthesized in our laboratory by co-precipitation method and applied isotherm and kinetic models for adsorption properties. XRD analysis were conducted to find crystal structure of synthesized MIO. Further SEM and XPS analysis was performed before and after phosphate adsorption, and BET analysis for surface characterization. Phosphate stock solution was prepared by KH2PO4 for characterization of phosphate adsorption, and batch experiment was conducted using 50 ml conical tube. Langmuir and Freundlich models were applied based on adsorption equilibrium test of MIO by initial phosphate solution. Pseudo first order and pseudo second order models were applied for interpretation of kinetic model by temperature. Surface area and pore size of MIO were found $89.6m^2/g$ and 16 nm respectively. And, the determination coefficient ($R^2$) value of Langmuir model was 0.9779, which was comparatively higher than that of Freundlich isotherm model 0.9340.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.691-698
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• 2016

This study was carried out to investigate the characterization of iron oxide nanotubes (INTs) by anodization method and applied adsorption isotherms and kinetic models for phosphate adsorption. SEM analysis was conducted to examine the INTs surface formation. Further XRD and XPS analysis were performed to observe the crystal structure of INTs before and after phosphate adsorption. AFM analysis was conducted to determine of Fe foil surface before and after anodization. Phosphate stock solution for adsorption experiment was prepared by $KH_2PO_4$. The batch experiment was conducted using 20 ml phosphate stock solution and $40cm^3$ of INTs in 50 ml conical tube. Adsorption isotherms were applied Langmuir and Freundlich models for adsorption equilibrium test of INTs. Pseudo first order and pseudo second order models were applied for interpretation of adsorption rate by reaction time. The determination coefficient ($R^2$) values of Langmuir and Freundlich models were 0.9157 and 0.8876 respectively.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.217-229
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• 2000

Adsorption equilibrium experiments for the phenol on granular activated carbon(16~25 mesh) and powder activated carbon(325 mesh) were carried out at $25{\pm}1^{\circ}C$ and the results were expressed with Freundlich isotherm. Adsorption rate experiments were executed in batch adsorption system under the condition that can be neglecting mass transfer resistance at the external surface of the particle. The results were analysed with the Miller's method to evaluate the linear driving force(LDF) adsorption rate constant. Fixed bed adsorption experiments were performed by adopting different flow rates in the activated carbon-phenol system at $25{\pm}1^{\circ}C$. The theoretical breakthrough curves were estimated with the simple constant pattern solution. The adsorption rate constant of LDF model was not a fixed value but variable with adsorption amount. The experimental results were better agreed with the estimation of breakthrough curve using the variable adsorption rate constant than the results estimated using the average fixed adsorption rate constant.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.930-937
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• 2007

Korean pine(Pinus densiflora) bark was evaluated for its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled barks were treated with 1 N NaOH or 1 N HCl to examine the effect of surface modification. For comparison, untreated bark was tested under same condition. Within the tested pH range between 3 and 6, NaOH treatment increased Cu(II) adsorption capacity by $139\sim184%$, while HCl treatment decreased it by $37\sim42%$. Maximum copper ion uptake by bark was observed at pH $5\sim6$, but pH of solution was not a potent influence. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto bark. For NaOH-treated bark, the calculated sorption capacity$(q_e)$ increased from 6.58 to 12.77 mg/g, while the equilibrium rate constant$(k_2)$ decreased from 0.284 to 0.014 g/mg/min as initial Cu(II) concentration doubled from 100 mg/L. A batch isotherm test using NaOH-treated bark showed that equilibrium sorption data were represented by both the Langmuir model and the Freundlich model. It was confirmed that carboxylic acid of bark was involved in the Cu(II) adsorption. For NaOH-treated bark, in particular, carboxylate ion produced by hydrolysis or saponification appeared to be a major functional roup responsible for the enhanced Cu(II) sorption.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.203-209
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• 2007

본 연구는 목재로서 활용가치가 적은 수피(bark)를 활용하여 수질오염물질을 제거할 수 있는 여과 시스템에 대한 기초연구로서 소나무의 일종인 loblolly pine(Pinus taeda L.) 수피의 인 ($PO_4-P$) 흡착특성을 연구하였다. 실험에 사용된 수피는 입상형태로서 polyallylamine hydrochloride로 전처리하여 회분식 등온 흡착실험을 수행하였다. 회분식 등온흡착실험은 수용액 pH 3~pH 8범위에서, 인의 농도별(10, 20, 30, 40 mg/L)로 수행하였다. pH 5에서 가장 높은 인 제거 효율을 나타냈으며, 수용액의 pH는 실험 후 pH 3으로 감소하였다. 이러한 감소는 수피에 의한 phosphate의 흡착이 Lewis acid-base 반응으로서 이 과정에서 $H^+$의 방출로 인하여 나타난 현상인 것으로 여겨지며, 주된 반응 메카니즘은 더 연구할 필요성이 있다. 인 흡착은 초기에 빠른 속도로 진행되었으며 대략 200분 이후에 평형에 도달하였고, 시간이 지날수록 흡착양이 증가하는 경향을 보였다. 인의 흡착특성 결과는 Langmuir 등온흡착식과 Freundlich 등온흡착식으로 설명될 수 있으며, 등온흡착식 적용결과, 흡착제에 대한 최대 흡착능은 7.14 mg/g 이며 다른 흡착제와 비교하여 더 높았다. 실험결과와 모델에 의한 흡착능을 비교하고자 pseudo second-order model을 적용하여 흡착 동역학 상수를 구하였다. 또한 EDXA분석으로 회분식 흡착실험 후 수피와 인이 결합되어있는 것을 확인할 수 있었다.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.53-61
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• 2011

This study was conducted to confirm the adsorption capacity of CFW(Carbonized Foods Waste), which is produced by the process of recycling waste, in PRB method that Electrokinetic(E/K) method was applied. The batch test was carried out to analyze the adsorption characteristics of CFW for adsorbing the organic compounds. The organic compounds used in the batch test were Phenanthrene and Trichloroethylene(TCE), and the anionic surfactant(SDS) and the nonionic surfactant(Brij$^{(R)}$30) were used for the surfactants. The results of the batch test confirmed that the adsorption efficiency of Phenanthrene was 99% and TCE was 26%. The each compounds compared with the adsorption isotherms, which is calculated by the Langmuir and Freundlich models. The results indicated that Phenanthrene is fitted to the linear Langmuir model, whereas the distribution of TCE is unclear. The results of the batch test used in surfactants confirmed that the adsorption efficiency of CFW using Phenanthrene was reduced to 6~8%. However, the adsorption efficiency of CFW in TCE was increased up to 81% by surfactants. Especially, the nonionic surfactant was excellent in the adsorption of CFW using TCE. Nevertheless, the adsorption efficiency of CFW in Phenanthrene was still higher than TCE. Therefore, the adsorption efficiency of CFW in Phenanthrene was better than in TCE. In PRB method using E/K method, the adsorption of CFW used nonionic surfactant is better to use than the anion surfactants on the organic compounds.

• Resources Recycling
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• v.25 no.4
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• pp.60-67
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• 2016

This study was conducted to establish the adsorption-desorption mechanism and the optimum condition of chromatographic operation for separations of heavy rare earth elements (Gd, Tb, Dy) using a p507-containing resin. By employing Langmuir and Freundlich isotherm together with pseudo first and second order kinetics, absorption-desorption reaction mechanism was investigated. Langmuir and Freundlich isotherm was applied under assumption that adsorption reaction occurs in form of monolayer, and because the result was identical to the assumption, now we know adsorption of heavy rare earth elements occurs in form of monolayer. Concerning the pseudo first and second order kinetic, the pseudo second order seemed to be more suitable to represent heavy rare earth element adsorption mechanism. By using the extraction chromatography to separate heavy rare earth elements, ${\alpha}^{Tb}_{Gd}=1.24$, and ${\alpha}^{Dy}_{Tb}=1.03$ were confirmed in eluent HCl 0.25 M which indicates almost perfect separations of three elements. Furthermore, as concentrations of eluent became higher, the resolution value decreased and the elution area got shortened.