• Clean Technology
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• v.26 no.1
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• pp.30-38
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• 2020

The kinetic and thermodynamic parameters of Acid Red 66, adsorbed by granular activated carbon, were investigated on areas of initial concentration, contact time, and temperature. The adsorption equilibrium data were applied to Langmuir, Freundlich, Temkin, Redlich-Peterson, and Temkin isotherms. The agreement was found to be the highest in the Freundlich model. From the determined Freundlich separation factor (1/n = 0.125 ~ 0.232), the adsorption of Acid Red 66 by granular activated carbon could be employed as an effective treatment method. Temkin's constant related to adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) showed that this process was physical adsorption. From kinetic experiments, the adsorption process followed the pseudo-second order model with good agreement. The results of the intraparticle diffusion equation showed that the inclination of the second straight line representing the intraparticle diffusion was smaller than that of the first straight line representing the boundary layer diffusion. Therefore, it was confirmed that intraparticle diffusion was the rate-controlling step. From thermodynamic experiments, the activation energy was determined as 35.23 kJ mol^-1, indicating that the adsorption of Acid Red 66 was physical adsorption. The negative Gibbs free energy change (ΔG = -0.548 ~ -7.802 kJ mol^-1) and the positive enthalpy change (ΔH = +109.112 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, respectively. The isosteric heat of adsorption increased with the increase of surface loading, indicating lateral interactions between the adsorbed dye molecules.

• 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.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.565-573
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• 2021

Isotherms, kinetics and thermodynamic properties for adsorption of Brilliant Green(BG), Quinoline Yellow(QY) dyes by activated carbon were carried out using variables such as dose of adsorbent, pH, initial concentration, contact time, temperature and competitive. BG showed the highest adsorption rate of 92.4% at pH 11, and QY was adsorbed at 90.9% at pH 3. BG was in good agreement with the Freundlich isothermal model, and QY was well matched with Langmuir model. The separation coefficients of isotherm model indicated that these dyes could be effectively treated by activated carbon. Estimated adsorption energy by Temkin isotherm model indicated that the adsorption of BG and QY by activated carbon is a physical adsorption. The kinetic experimental results showed that the pseudo second order model had a better fit than the pseudo first order model with a smaller in the equilibrium adsorption amount. It was confirmed that surface diffusion was a rate controlling step by the intraparticle diffusion model. The activation energy and enthalpy change of the adsorption process indicated that the adsorption process was a relatively easy endothermic reaction. The entropy change indicated that the disorder of the adsorption system increased as the adsorption of BG and QY dyes to activated carbon proceeded. Gibbs free energy was found that the adsorption reaction became more spontaneous with increasing temperature. As a result of competitive adsorption of the mixed solution, it was found that QY was disturbed by BG and the adsorption reduced.

• The Journal of Engineering Geology
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• v.5 no.1
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• pp.75-93
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• 1995

This study investigates the adsorption capacity of the gibbsite and the clay on the development of admixed liner. The gibbsite is produced as a by-product in the pretreatment process for cleaning and coloring of Alurninurn sash. From the study, following conclusions were obtained: 1) The adsorption of metals such as Cu(II), Cd(II), and Ni(II) and phenol on gibbsite and l:entonite was equilibrated rather quickly(12 ~48 hrs ). 2) The rate and extent of adsorption is a function of surface area the adsorbent having. 3) The Larigmuir isotherm is found to be more suitable than Freundlich isotherm for the adsorption analysis of heavy metals on gibbsite and bentonite. 4) In case of phenol, Freundlich isotherm, whose N value is close to 1, i.e., close to linear isotherm, is more fit to describe the adsorption on gibbsite and bentonite. 5) The amount of metals and phenol adsorbed is found to be in the following order : Adsorbent : $2{\mu}m-Al(OH)_3$ > Mixed Solid > $12{\mu}m-Al(OH)_3$ > Na-Bentonite > $30{\mu}m-Al(OH)_3$

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.606-616
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• 2011

The objectives of this study were to evaluate the applicability of adsorption models for adsorption properties of adsorbents. For this study, adsorption experiment of $NO_3^-$ ion using anion exchange resin has been investigated under adsorption equilibrium and kinetic in bach process. Adsorption equilibrium experiment were carried out that two conditions is change of adsorbate concentration and change of adsorbent weight. Experiment results have been analyzed by adsorption isotherm models, energy models and kinetic models. Under the condition of change of adsorbate concentration was best described by Sips and Redlich-Perterson isotherm models. However case of change of adsorbent weight was described by Langmuir isotherm models. It seems reasonable to assume that isotherm model was dominated by multiple mechanism according to experiment condition.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.146-154
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• 2015

Domestic railway industry has grown in numbers, scale of railway ndustrial and operation because was focused on an environmentally sustainable transportation. However, it is not enough to treat and prevent heavy metals which occur as the railway operation increases. The heavy metals occurred when the operating railway and it will be flow into water system with rainfall effluent during rainfall. will flow out along with the rainfall effluent when rainfall comes. In case of a railway bridge, In particular, heavy metals were flow into the water system without any treatment from railway bridges where located nearby rivers and lakes. So, rainfall effluent from railway facilities was occurred pollution of water system. For the prevent of heavy metal runoff during rainfall, the adsorptivity of material in railway roadbed is important.In this study, adsorptivity of gravel which is main gravel and blast-furnace slag were conducted adsorption test and deducted Freundlich's and Langmuir's isothermal adsorption equations. Safety as railway subbase course material was evaluated using modeling. As a result, absorption amount of slag, Cd and Cu, was shown higher than gravel and Pb along with Zn showed higher absorption amount of gravel. However, absorption amount of slag was shown higher than gravel used as railway subbase course material as time passes by. Absorption features had more suitable determination coefficient of heavy metals in warm absorption type such as Langnmuir compared to warm absorption type like Freundlich. To add, they showed less transformation by about 10% compared to gravel in safety evaluation through modeling. This is a railway subbase course material that prevents water outflow of heavy metal thus we can know slag is needed to be used.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.113-121
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• 2020

In batch experiments, the adsorption of 7-epi-10-deacetylpaclitaxel was studied using Sylopute. Experimental equilibrium data were applied to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Among the four isotherm models tested, the Langmuir isotherm model gave the highest accuracy. The adsorption capacity was found to decrease with increases in temperature and the adsorption of 7-epi-10-deacetylpaclitaxel onto Sylopute was a favorable physical process. Adsorption kinetic data agreed very well with the pseudo-second-order kinetic model, while boundary layer diffusion and intraparticle diffusion did not play a key role in the adsorption process. The process of 7-epi-10-deacetylpaclitaxel adsorption onto Sylopute was exothermic and nonspontaneous. Also, the adsorption isosteric heat was independent of surface loading indicating an energetically homogeneous adsorbent.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.78-85
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• 2007

This study provides an attempt to evaluate sanding wastes, generated from a chemical company as a reused adsorbent. Organic impurities in the raw sanding wastes were removed by calcination at $550^{\circ}C$. Aluminum was a major inorganic composition in the raw sanding wastes and increased from 29.09% to 52.73% after calcination. Dissolved concentrations of heavy metals from the calcined sample were below 0.3 mg/L in a stability test at pH 2. From the pH-edge adsorption experiments with the calcined sanding wastes, As (V) was found to follow an anionic-type adsorption. Adsorption isotherm obtained with variation of the dosage of the calcined sanding wastes was better described by Freundlich equation than Langmuir one. Freundlich constants of K and 1/n were 4.244 and 0.316, respectively. The As (V) adsorption capacity of calcined sanding wastes estimated from Langmuir isotherm was 13.25 mg/g. From this study, the calcined sample was identified as a good reusable adsorbent in the view point of stability and adsorption capacity on As (V).

• Resources Recycling
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• v.9 no.6
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• pp.9-14
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• 2000

Comparing the adsorption characteristics of coconut shell activated carbon (CSAC) and waste paint activated carbon (WPAC), Freundlich adsorption isotherms of alkylbenzene sulfonate (ABS) obtained from the secondary treatment water of H company and effluent of D company were estimated q=23.12 $C^{0.42}$ , q=18.32 $C^{0.38}$ with WPAC and $q=36.76C^{1.37}$ /, q=26.67 $C^{0.42}$ with CSAC respectively. In the case of H company, breakthrough time of the ABS using CSAC by continuous experiment was estimated 680 minute md that of WPAC was 610 minute. In the case of D company effluent, CSAC was estimated 720 minute, and that of WPAC was estimated 640 minute to reach the breakthrough. From the above results, it is possible to replace the coco-nut shell activated carbon with wasted paint activated carbon.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.166-172
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• 1999

Fixed-bed adsorption of metal ions on chitosan bead was studied to remove heavy metal ions in waste water. Chitin was extracted from carb shell and chitosan was prepared by deacetylation of the chitin. The chitosan in bead was used as an adsorbent for heavy metal ions. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual metal ion ($Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$) on chitosan bead. Adsorption strength of metal ions decreased in the order of $Cu^{2+}$>$Co^{2+}$>$Ni^{2+}$ ion. Breakthrough curves of single and multicomponent adsorption for metal ions were obtained from the experimental results of fixed-bed adsorption. The breakthrough curves were analyzed by simulation with fixed-bed adsorption equation based on LDFA (linear driving force approximation) adopted LAS (ideal adsorbed solution) theory which can predict multi-component adsorption isotherm from individual adsorption isotherm. The behavior of fixed bed adsorption for single and multi-component system could be nicely simulated by the equation.