• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.112-118
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• 2018

Adsorption equilibrium, kinetic and thermodynamic parameters of a brilliant green from aqueous solutions at various initial dye concentration (10~30 mg/L), contact time (1~24 h) and temperature (298~318 K) on zeolite were studied in a batch mode operation. The equilibrium adsorption values were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich model. The results indicate that Langmuir and Freundlich model provides the best correlation of the experimental data. Base on the estimated values of Langmuir dimensionless separation factor ($R_L=0.041{\sim}0.057$) and Freundlich constant (1/n=0.30~0.47), this process could be employed as effective treatment method. calculated values of adsorption energy by Dubinin-Radushkevich model were 1.564~1.857 kJ/mol corresponding to physical adsorption. The adsorption kinetics of brilliant green were best described by the pseudo second-order rate model and followed by intraparticle diffusion model. Thermodynamic parameters such as activation energy, free energy, enthalpy and entropy were calculated to estimate nature of adsorption. negative Gibbs free energy (-10.3~-11.4 kJ/mol), positive enthalpy change (49.48 kJ/mol) and Arrehenius activation energy (27.05 kJ/mol) indicates that the adsorption is spontaneous, endothermic and physical adsorption process, respectively.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.700-705
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• 2012

The present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of T-N and T-P in water. Here, we investigated adsorption efficiency and Freundlich constants k and 1/n of each adsorbent. It was found that fly ash has not adsorptive capability for both T-N and T-P in water. Adsorption of T-N from water by loess has not occurred, but showed that adsorption efficiency for T-P reached approximately 57.5% at equilibrium time of 24 hr and room temperature. Activated carbon was shown to be an effective adsorbent for adsorption of T-N from water. Freundlich constant 1/n value of activated carbon represented that adsorptive capability of activated carbon is almost equivalent to loess.

• Resources Recycling
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• v.17 no.2
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• pp.63-69
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• 2008

The adsorption features of $Ni^{2+}$ onto spent alkaline manganese batteries powder have been investigated with the adsorbent dose, initial concentration of adsorbate and temperature as the experimental variables. The adsorption reaction of $Ni^{2+}$ ion followed the pseudo-second order rate model, and the adsorption rate constants($k_2$) decreased with increasing initial concentration of nickel ion. The equilibrium adsorption data were fitted to the Langmuir and Freundlich models. The Freundlich model represents the equilibrium data better than the Langmuir model in this initial adsorbate concentration range. As the temperature increased, the adsorbed amount of nickel ion at equilibrium was also increased, which indicated that the adsorption reaction was endothermic. Based on the experimental results obtained along with temperatures, thermodynamic parameters such as ${\Delta}H^{\circ},\;{\Delta}G^{\circ},\;and\;{\Delta}S^{\circ}$ were calculated.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1213-1223
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• 2000

The adsorption characteristics of phenol has been studied by using CDQ (Cokes Drying Quenching) dust as an adsorbent. The adsorption capacity of CDQ dust was shown to be 42% about removal for 300 ppm phenol solution at the equilibrium adsorption time of 60 min. Removal percentage of phenol increased as the initial phenol concentration was raised in the experimental conditions and the adsorption behavior was explained well by Freundlich adsorption isotherm. Kinetic study showed that the adsorption followed 1st, 1.5th, and 2nd-order rate equation in the sequence as the adsorption time passed. Since the adsorption amount of phenol was increased as the adsorption temperature was raised, the adsorption was thought to be endothermic, and several thermodynamic parameters have been calculated based upon experimental data. Adsorbed amount of phenol on CDQ dust changed little according to the variation in the solution pH except for the slight decrease under the strong alkaline condition.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.61-67
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• 1997

Heavy metal adsorption by microbial cells is an alternative to conventional methods of heavy metal removal and recovery from metal-bearing wastewater The waste Sac-chuomyces cerevisiae is an inexpensive, relatively available source of biomass for heavy metal biosorption. Biosorption was investigated by free and immobilized-S. cerevisiae. The order of biosorption capacity was Pb>Cu>Cd with batch system. The biosorption parameters had been determined for Pb with free , cells according to the Freundlich and Langmuir model. It was found that the data fitted reasonably well to the Freundlich model. The selective uptake of immobilized-S. cerevisiae was observed when all the metal ions were dissolved in a mixed metals solution(Pb, Cu, Cr and Cd). The biosorption of mixed metals solution by immobilized-cell was studied in packed bed reactor. The Pb uptake was Investigated in particular, as it represents one of the most widely distributed heavy metals in water. We also tested the desorption of Pb from immobilized-cell by us- ing HCI, $H_2SO_4$ and EDTA.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.64-70
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• 2015

Batch experiment studies were carried out for adsorption of congo red using granular activated carbon with various parameters such as activated carbon dose, pH, initial dye concentration, temperature and contact time. Equilibrium experimental data are fitted to the Langmuir, Freundlich, Temkin and Dubin-Radushkevich isotherm equations. From Freundlich's separation factor (1/n) estimated, adsorption could be employed as effective treatment method for adsorption of congo red from aqueous solution. Base on Temkin constant (B) and Dubinin-Radushkevich constant (E), this adsorption process is physical adsorption. Adsorption kinetics has been tested using pseudo-first order and pseudo second order models. The results followed pseudo second order model with good correlation. Adsorption process of congo red on granular activated carbon was endothermic (${\Delta}H$=42.036 kJ/mol) and was accompanied by decrease in Gibbs free energy (${\Delta}G$=-2.414 to -4.596 kJ/mol) with increasing adsorption temperature.

• Journal of the Korean Chemical Society
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• v.61 no.5
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• pp.238-243
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• 2017

In this study, water treatment sludge carbonized with $400^{\circ}C$ was tested as an adsorbent for the removal of Pb and Cd in water. The carbonized sludge was characterized by thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), and surface area analysis. Carbonized sludge exhibited much higher specific surface area and total pore volume than water treatment sludge itself. In batch-type adsorption process, carbonized sludge represented better adsorption performance for Pb than Cd, achieving 90~98% at the concentrations conducted in the experiments. Equilibrium data of adsorption were analyzed using the Freundlich and Langmuir isotherm models. It was seen that both Freundlich and Langmuir isotherms have correlation coefficient $R^2$ value larger than 0.95. The results of studies indicated that carbonized water treatment sludge by heat treatment could be used as an efficient adsorbent for the removal of Pb and Cd from water.

• Clean Technology
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• v.7 no.2
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• pp.141-149
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• 2001

The effects of various factors such as adsorption temperature, interstitial velocity, species and concentration of adsorbates(benzene and toluene) and aspect ratio(L/D) on adsorption characteristics were investigated in a fixed bed with activated carbon. The breakthrough time in a fixed bed was decreased with the increasing of adsorption temperature, interstitial velocity and concentration of adsorbates. The interstitial velocity, concentration of adsorbates and adsorption temperature had influenced considerably upon the MTZ(mass transfer zone) and LUB(length of unused bed) obtained through the breakthrough curves, while aspect ratio(L/D) had smaller effect than former factors. Especially, the concentration of adsorbates among factors have the largest effect on MTZ and LUB. From comparison with the model isotherms, such as the Langmuir, Freundlich and Langmuir-Freundlich, the experimental isotherm data of benzene and toluene agreed farily well to three adsorption isotherm models.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.6-12
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• 2000

This study was carried out to determine the adsorption characteristics of eight pesticides on thirty citrus orchard soil so soil samples were taken from nineteen soil series containing different fractions of organic carbon(Foc). The adsorption characteristics for eight pesticides fitted to Freundlich isotherms. The adsorption isotherms showed C-type for alachlor and chlorpyrifos, L-type for linuron and diniconazole. and S, C, and L-types for metribuzin, metolachlor, and alachlor with increasing Foc, respectively. In particular, the adsorption of chlorothalonil showed S, C, L, and H-types with increasing Foc. Distribution coefficient(Kd) values of metribuzin, metolachlor, and alachlor were below $10\;Lkg^{-1}$ and increased linearly with Foc. Kd values of linuron, diuron and chlorothalonil increased exponentially to 60, 200, and $400\;Lkg^{-1}$, respectively and those of diniconazole and chlorpyrifos increased logarithmically. Kf value. Freundlich adsorption coefficiient, increased with Kd in the same manner with Kd. Furthermore, the linearity of Kf value was larger than that of Kd value.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.37-44
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• 1987

Adsorption characteristics of chloroform, carbon tetrachloride, and crystal violet were investigated in single-and bi-solute systems. Single-solute adsorption for each solute was well described by Freundlich equation. Severe inhibition was recorded in bi-solute adsorption systems despite of low solute concentration of less than 1 mg/l. Inhibition of chloroform adsorption by carbon tetrachloride, similar compound in chemical structure, was much higher than by crystal violet of which chemical structure is quite different. Highest inhibition was observed at crystal violet adsorption by chloroform. While, inhibition caused by each other was almost equal between chloroform and carbon tetrachloride. Bi-solute adsorption was well described by Friz-Schl${\ddot{u}}$nder model and by much simpler 3 parameter Freundlich equation.