• Clean Technology
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• v.19 no.4
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• pp.430-436
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• 2013

In this study, experiments on the static adsorption of benzene were carried out using activated carbon made from Pinus koraiensis which is normally discarded waste timber in South Korea. The experiment were performed at 303.15 K, 318.15 K and 333.15 K under the pressure up to 7.999 kPa. Isothermal adsorption curves were obtained using Langmuir isotherm, Freundlich isotherm and Toth isotherm for comparison. Based on the fitting, the adsorption quantity of Benzene (q), the isothermal adsorption curves obtained from Langmuir isotherm and Toth isotherm showed the higher accuracy. Although there was little difference in accuracy between result from Langmuir isotherm and that from Toth isotherm, the adsorption quantity of Benzene (q) was expressed in terms of Langmuir isotherm because less parameters were required for Langmuir isotherm than for Toth isotherm. Moreover SEM images of the activated carbon from Pinus koraiensis and the commercial activated carbon were taken to observe the pore size development. The results showed that the perforation development of activated carbon from Pinus koraiensis (waste timber) was better than that of commercial activated carbon (DARCO A.C., SPG-100 A.C.). Adsorption quantity of benzene on activated carbon from Pinus koraiensis was confirmed to be higher than that on commercial activated carbon. Therefore, we may conclude that it is feasible to commercialize the process to manufacturing activated carbon from waste timber.

• Clean Technology
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• v.9 no.4
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• pp.153-161
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• 2003

This study was carried out as a basic experiment for development of adsorption process in which benzene and toluene was adsorbed on activated carbon. In the static adsorption experiment, Adsorption character of benzene and toluene was studied by change of temperature and pressure. Activated carbon 12~20mesh and activated carbon 20~40mesh was used as adsorbents, Benzene, toluene and nitrogen as adsorbates. Experimental data were obtained to fitted to Langmuir isotherm and dependence was acquired. Parameters of adsorption heat and adsorption constant was obtained. Static adsorption experiment for binary mixtures confirmed that Langmuir isotherm parameters could be applicable to Extended Langmuir isotherm. Experimental technique used in this study only requires pressure measurement and this technique is different from the conventional method which measures gas mole compositions before adsorption and after adsorption. The dynamic adsorption experiment was carried out and the experimental results was compared with the computer simulation results. In this study, basic data was acquired to decide adsorption conditions in the process.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.672-676
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• 1999

Adsorption isotherm is the most fundamental information in adsorption separation-process. Directly from the elution profile of a peak, the elution-curve method and frontal analysis(FA) were utilized to measure the adsorption isotherm in this work. Using RP-HPLC, sample and the buffer added in mobile phase were 5'-GMP and sodium phosphate, respectively. In this experimental condition, the retention time was decreased with increase in the injected mass of sample. And the front part of a peak was very stiff, so Langmuir adsorption isotherm might be applied. By the elution-curve method, the parameters used in the isotherm were obtained by optimization method, while by the FA, the concentrations of stationary phase were measured from the elution curve and the isotherm was determined by regression analysis. Compared to FA, the consumption of sample was less, and only one or two injections were needed by the elution-curve method. Finally, the effect of concentration of sodium phosphate in mobile phase on the parameters of the isotherm was investigated.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.122-126
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• 2002

Contaminant transport in porous media is characterized by solving an advection-dispersion equation(ADE). The ADE can cover equilibrium phenomena of interest, which include sorption, decay, and chemical reactions. Among these phenomena, sorption mechanism is described by several types of sorption isotherm. If we assume the sorption isotherm as linear, the solution of ADE can be easily procured. However, if we consider the sorption isotherm as non-linear isotherm like a Dual Reactive Domain Model (DRDM), the resulting differential equation becomes non-linear. In this case, the solution of ADE cannot be easily acquired by an analytic method. In this paper, we present the numerical analysis of ADE using a DRDM. The results reveal that even if sorption data may be fitted well using linear or non-linear isotherm, the characteristics of contaminant transport of the two cases are different from each other. To be concrete, the retardation of linear isotherm has stronger effect than that of the DRDM. As the non-linearity of sorption isotherm increases, the difference of retardation effects of the two cases becomes larger. For a pulse source, the maximum concentration of the linear model is higher than that of the DRDM, but the plume of the DRDM moves faster than that of the linear model. Behaviors of contaminant transport using the DRDM are consistent with common features of a linear model. For instance, biodegradation effect becomes larger as time goes by The faster the seepage velocity is, the faster the plume of contaminant moves. The plume of the contaminant is distributed evenly over overall domain in the event of high dispersion coefficient.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.750-757
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• 2009

The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.245-250
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• 2008

Adsorption experiment was carried out to find the adsorption capacity and characteristics of heavy metals(Cd, Pb) onto soil and mixed soil with food compost. Result showed that mixed soil having higher organic content adsorbed more heavy metal than soil, indicating that food compost can be used effectively to prevent soil pollution. Linear adsorption isotherm which adopted to find the adsorption characteristics was used to calculate Retardation Factor(R). The value of Retardation Factor(R)s of Pb and Cd in mixed soil, found as 34.54, 24.42 respectively, are higher than those in soil which were found as 4.64, 3.67, respectively. The value of Retardation Factor(R) using Freundlich adsorption isotherm could be presented by the functions of concentration and showed similar result as the linear one. But Freundlich adsorption isotherm showed higher relationship than linear one and the retardation factor(R) from freundlich adsorption isotherm was thought as more effective method to assess adsorption capacity because it could reflect gradient and intercept of the isotherm.

• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.89-96
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• 2017

This study proposed adsorption of Pb(II) ions from aqueous solution using activated carbon prepared from areca catechu shell (ACS AC) using Timphan Method. The effects of independent variables on adsorption kinetic and isotherm have been investigated by conducting experiments in batch mode at neutral pH. The structural characterization of adsorbent was done by FT-IR and SEM analysis. The Pb(II) adsorption was correlated very well with the pseudo second-order kinetic (PSOKM) and Langmuir isotherm models (LIM). Increasing NaOH mass for activation and adsorption temperature increased weakly all the parameters of adsorption kinetic and isotherm. The Pb(II) ions adsorption capacity of the ACS AC at 27 and $45^{\circ}C$ was 50.51 and 55.25 mg/g, respectively. Thermodynamic parameters were determined, and the results confirmed the Pb(II) ions adsorption should be endothermic and spontaneous process, and both physical and chemical adsorption should be taken place.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.331-338
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• 2004

The Separation of two amino acids, phenylalanine and tryptophan, was carried out using laboratory simulated moving bed (SMB) chromatography. The SMB process consisted of four zones, with each zone having 2 columns. The triangle theory was used to obtain the operating conditions for the SMB. The mass transfer coefficients of the two amino acids were obtained from the best-fit values by comparing simulated and experimental pulse data. The competitive adsorption isotherms of the two amino acids were obtained by single and binary frontal analyses, taking into consideration the competition between the two components. A competitive Langmuir isotherm, obtained from single-component frontal chromatography, was used in the first run, and the isotherm from binary frontal chromatography in the second, with the flow rate of zone 1 modified to improve the purity. Compared to the first and second runs, the competitive Langmuir isotherm from the binary frontal chromatography Showed good agreement with the experimental results. Also, adjusting the flow rate in zone 1 increased the purity of the products. The purities of the phenylalanine in the raffinate and the tryptophan in the extract were 99.84 and $99.99\%$, respectively.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.59-65
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• 1999

For a cosmetic plant wastewater containing surfactants of high concentration, adsorption treatment by granular activated carbon(GAC) having different pore size distribution was studied. Three sorts GACs were used and regenerated afterwards with methanol. Experiments were composed of batch process and column test for both virgin and regenerated GACs. Following conclusions were drawn from the study: Methylene blue activating substance(MBAS) adsorption data from the batch tests for three GACs are described well by BET isotherm and Freundich isotherm. Simulation with the BET isotherm shows that maximum adsorption appears to be affected not only by specific surface area but also by pore size distribution. Maximum adsorption from the BET isotherm for MBAS appears to diminish as the number of reactivation increases. The diminishing ratio of maximum adsorption appears to decrease as the pore size decreases. Recovery ratio of the methanol by vacuum evaporation from the spent methanol ranges from 95% to 97%.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.537-540
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• 2006

Over the past few decades, a considerable number of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in modeling of ionic flows. However, the majority of these researches have not dealt with the chloride binding isotherm based on the mechanism, although chloride binding capacity can significantly impact on the total service life of concrete under marine environment. The purpose of this study is to develop the model of chloride binding isotherm based on the individual mechanism. It is well known that chlorides ions in concrete can be present; free chlorides dissolved in the pore solution, chemical bound chlorides reacted with the hydration compounds of cement, and physical bound attracted to the surface of C-S-H grains. First, sub-model for water soluble chloride content is suggested as a function of pore solution and degree of saturation. Second, chemical model is suggested separately to estimate the response of binding capacity due to C-S-H and Friedel's salt. Finally, physical bound chloride content is estimated to consider a surface area of C-S-H nano-grains and the distance limited by the Van der Waals force. The new model of chloride binding isotherm suggested in this study is based on their intrinsic binding mechanisms and hydration reaction of concrete. Accordingly, it is possible to characterize chloride binding isotherm at the arbitrary stage of hydration time and arbitrary location from the surface of concrete. Comparative study with experimental data of published literature is accomplished to validity this model.