• Advances in environmental research
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• 제12권1호
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• pp.17-40
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• 2023

This article presents studies of the adsorption process in a continuous system of fluoride solutions at a concentration of 30 mg/L using a bone char packed in fixed-bed columns, as well as regeneration studies in the same system using HNO₃, HCl and NaOH at 0.01, 0.1 and 1 M. The Thomas Model, Artificial Neural Networks (ANNs), Numerical Integration and Mass Transfer Zone were used for the modeling of asyemmetrical breakthrough curves obtained from the fluoride adsorption on bone char. The maximum adsorption capacity of the breakthrough curves was estimated, and various design parameters of the columns were obtained for the different operating conditions. Results showed that an improvement in the modeling capabilities of the Thomas model can be obtained using ANNs. Moreover, ANNs are useful for determining reasonable and accurate design parameters of packed-bed adsorption columns. This modeling approach can be useful for the process system engineering of dynamic adsorption systems involved in the field of water treatment and purification. It is important to highlight that the obtained results indicate that, when using HCl or HNO₃ at a concentration of 0.1 M, a large number of adsorption-desorption cycles are obtained and, therefore, the highest values of adsorption capacity, which leads to a reduction in operation costs.

• 한국환경과학회지
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• 제8권2호
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• pp.211-219
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• 1999

Surface complexation models(SCMs) have been performed to predict metal ion adsorption behavior onto the mineral surface. Application of SCMs, however, requires a self-consistent approach to determine model parameter values. In this paper, in order to determine the metal ion adsorption parameters for the triple layer model(TLM) version of the SCM, we used the zeta potential data for Zeolite and Kaolinite, and the metal ion adsorption data for Pb(II) and Cd(II). Fitting parameters determined for the modeling were as follows ; total site concentration, site density, specific surface area, surface acidity constants, etc. Zeta potential as a new approach other than the acidic-alkalimetric titration method was adopted for simulation of adsorption phenomena. Some fitting parameters were determined by the trial and error method. Modeling approach was successful in quantitatively simulating adsorption behavior under various geochemical conditions.

• Advances in environmental research
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• 제7권1호
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• pp.29-37
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• 2018

A simple mathematical model for predicting fixed bed adsorption dynamics is described. The model is characterized by a linear adsorption isotherm and a linear driving force expression for mass transfer. Its analytic solution can be approximated with an algebraic equation in closed form which is easily evaluated by spreadsheet computation. To demonstrate one application of the fixed bed model, a previously published adsorption system is used as a case study in this work. The adsorption system examined here describes chromium breakthrough in a fixed bed adsorber packed with imidazole functionalized adsorbent particles and is characterized by a nonlinear adsorption isotherm. However, the equilibrium behavior of the fixed bed adsorber is in essence governed by a linear adsorption isotherm due to the use of a low influent chromium concentration. It is shown that chromium breakthrough is predicted reasonably well by the fixed bed model. The model's parameters can be easily extracted from independent batch experiments. The proposed modeling approach is very simple and rapid, and only Excel is used for computation.

• Membrane and Water Treatment
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• 제9권5호
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• pp.363-371
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• 2018

In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.

• 한국정보통신학회논문지
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• 제17권7호
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• pp.1709-1714
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• 2013

생물 및 화학공정의 정제과정은 여러 단계의 크로마토그래프 분리공정을 포함할 수 있다. 최근 생명공학의 발전과 더불어 중요시되는 단백질과 같은 생물 분자의 분리를 위하여 크로마토그래피 흡착공정에 많은 관심이 집중되고 있다. 따라서 본 논문에서는 흡착공정 모델링을 위한 시뮬레이션 시스템을 설계 및 구현하였다. 본 시스템은 흡착공정 모델링에 따른 시뮬레이션 결과 값을 시각화하거나 곡선 그래프로 나타나도록 하였다. 본 시스템의 개발은 회분식 흡착공정 모사프로그램에 중점을 두어 국한되어 개발하였다.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.218-222
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• 1998

Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

• KSBB Journal
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• 제14권5호
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• pp.550-560
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• 1999

There have been many research efforts on biofilter modeling including Ottengraf et al. who derived a model equation for the concentration profile of pollutants(e.g., VOCs) in the biolayer and solved their outlet concentration of the waste gas stream through biofilter. However, for most of research works done so far, the effects to explain the effect of adsorption of organic particles to medium(i.e., adsorbent) have been ignored. In this work biofilter modeling accompanying process lumping has been proposed and the theoretical effect of adsorption property of the medium, on the biofilter performance of eliminating organic components in waste gas stream, is intensively discussed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.243-247
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• 2004

Tile development of a porous iron-oxide coated sand filter system can be modelled with the analytical solution of tile transport equation in order to obtain the operating parameters and investigate the mechanism of arsenic removal. The adsorbed amount from the model simulation showed the limitation of adsorption removal during arsenic transport. A loss reaction term in the transport equation plays a role in the mass loss in column conditions, and then resulted into the better model fitting, particularly, for arsenate. Further, the competitive oxyanions delayed the breakthrough near MCL (10 $\mu$g/L) due to the competitive adsorption. This is the reason why arsenate can be strongly attracted in tile interface of an iron-oxide coated sand, and competing oxyanions can occupy the adsorption sites. Therefore, arsenic retention was regulated by non-equilibrium of arsenic adsorption in a porous iron-oxide coated sand media. The transport-limited process seemed to be affect the arsenic adsorption by coated sand.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.133-136
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• 2000

Soil decontamination process was conducted to study adsorption and modeling characteristic of Sr$^{2+}$ ion using citric acid and water system with TRIGA soil. When the concentration of citric acid was increased, the BTC of Sr$^{2+}$ ion was to be closed to the BTC of $^3$$H_2O$ at experiments of soil adsorption. Beside, when the concentration of citric acid was under 0.01M Sr$^{2+}$ ion, BTLs was asymmetry. It was characteristic of nonequilibrium adsorption. R and $K_{p}$ , were decreased to be increased the concentration of citric acid. Asymmetry modeling was nearly the same to be compare with symmetry modeling in decontamination process, when the concentration of citric acid was decreased. Result of experiment was agree with asymmetry and symmetry model, when the concentration of citric acid was increased.eased.

• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.16-25
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• 1998

This study was carried out to compare vibrational properties and adsorption among shellac, cashew finished plate and untreated plate of Sitka spruce(Picea sitchensis Carr). By the method of statistical regression modeling, the fundamental resonance frequency of finished plate was higher than that of untreated plate. The fundamental resonance frequency of cashew finished plate was higher than that of shellac finished plate. By the method of modal analysis, mode frequency ratio of cashew finished plate was higher than that of shellac finished plate. Amounts of adsorption of finished plate was lower than that of untreated plate, and amount of adsorption of cashew finished plate was lower than that of shellac finished plate. It was clarified that the vibrational properties and adsorption of finished plate were superior to those of untreated plate. The vibrational properties and adsorption of cashew finished plate was superior to those of shellac finished plate.