• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.55-62
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• 1996

The purpose of this study is the evaluation of adsorption capacity of casts for heavy metals comparing with the activated carbon. The casts was obtained from vermicomposting of the mixed organic sludges which were generated from the treatment facilities for leather wastewater and cattle wastewater. The physico-chemical characteristics of cast was investigated. Also, the batch adsorption experiments of cast and activated carbon for heavy metals were carried out, and the results were analyzed by Freundlich isotherm. The buffering capacity to the acidic wastewater was founded in the cast, and the cation exchange capacity of cast impling adsorption capacity for soluble substances was evaluated as about 55me/100g. Those were implied that the cast have a large potential as a good adsorbent for soluble pollutants in wastewater. From the results of batch experiments, the removal efficiencies of tested various heavy metals including Pb, Cu, Cd, and Cr were very high value as 89-98% for the activated car-bon, and 80~95% for the casts except for Zn. The adsorption equilibriums for the two materials were achieved within 90 minutes. The order of preferable metals in the adsorption was found to be Pb>Cu>Cd>Cr>Zn on the cast and to be Pb>Cd>Cu>Cr>Zn on the activated carbon, respectively. From the above results, it might be con-cluded that cast is effectively available as a good adsorbent to treating the heavy metal bearing wastewater.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.667-674
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• 2020

The adsorption of reactive orange 16 (RO 16) dye by activated carbon was investigated using the amount of adsorbent, pH, initial concentration, contact time and temperature as adsorption variables. The investigated process parameters were separation coefficient, rate constant, rate controlling step, activation energy, enthalpy, entropy, and free energy. The adsorption of RO 16 was the highest at pH 3 due to the electrostatic attraction between the cations (H⁺) on the surface of the activated carbon and the sulfonate ions and hydroxy ions possessed by RO 16. Isotherm data were fitted into Langmuir, Freundlich and Temkin isotherm models by applying the evaluated separation factor of Langmuir (RL=0.459~0.491) and Freundlich (1/n=0.398~0.441). Therefore, the adsorption operation of RO 16 by activated carbon was confirmed as an appropriate removal method. Temkin's adsorption energy indicated that this adsorption process was physical adsorption. The adsorption kinetics studies showed that the adsorption of RO 16 follows the pseudo-second-order kinetic model and that the rate controlling step in the adsorption process was the intraparticle diffusion step. The positive enthalpy change indicated an endothermic process. The negative Gibbs free energy change decreased in the order of -3.16 <-11.60 <-14.01 kJ/mol as the temperature increased. Therefore, it was shown that the spontaneity of the adsorption process of RO 16 increases with increasing temperature.

• 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).

• Clean Technology
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• v.17 no.4
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• pp.346-352
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• 2011

The adsorption characteristics of propineb pesticide onto activated carbon has been investigated for the adsorption in aqueous solution with respect to initial concentration, contact time and temperature in batch experiment. The Langmuir and Freundlich adsorption models were applied to described the equilibrium isotherms and isotherm constants were also determined. The Freundlich model agrees with experimental data well. slope of isotherm line indicate that activated carbon could be employed as effective treatment for removal of propineb. The pseudo first order, pseudo second order kinetic models were use to describe the kinetic data and rate constants were evaluated. The adsorption process followed a pseudo second order model, and the adsorption rate constant($k_2$) decreased with increasing initial concentration of propineb. The activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption. The estimated values for change of free energy were -7.28, -8.27 and -11.66 kJ/mol over activated carbon at 298, 308 and 318 K, respectively. The results indicated toward a spontaneous process. The positive value for change of enthalpy, 54.46 kJ/mol, found that the adsorption of propineb on activated carbon is an endothermic process.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.327-332
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• 2013

Batch experiments were carried out for adsorption equilibrium, kinetics and thermodynamic parameters of the brilliant brown R onto granular activated carbon. The operating variables studied were the initial dye concentration, contact time and temperature. Experimental equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption isotherm by linear regression method. The equilibrium process was well described by Freundlich isotherm model and from the determined separation factor (1/n), granular activated carbon could be employed as an effective treatment for the removal of bismarck brown R. From kinetic experiments, the adsorption processes were found to confirm the pseudo second order model with a good correlation and the adsorption rate constant ($k_2$) increased with increasing adsorption temperature. Thermodynamic parameters like the activation energy, change of Gibbs free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption in the temperature range of 298~318 K. The activation energy was determined as 8.73 kJ/mol for 100 mg/L. It was found that the adsorption of bismarck brown R on the granular activated carbon was physical process. The negative Gibbs free energy change (${\Delta}G$ = -2.59~-4.92 kJ/mol) and the positive enthalpy change (${\Delta}H$ = +26.34 kJ/mol) are indicative of the spontaneous and endothermic nature of the adsorption process.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.96-102
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• 2014

Adsorption of metanil yellow onto granular activated carbon were studied in a batch system. Various operation parameters such as adsorbent dosage, pH, initial concentration, contact time and temperature were optimized. Experimental equilibrium adsorption data were analyzed by Langmuir and Freundlich adsorption isotherm. The equilibrium process was described well by Freundlich isotherm model. From determined separation factor (1/n), adsorption of metanil yellow by granular activated carbon could be employed as effective treatment method. By analysis of kinetic experimental data, the adsorption process were found to confirm to the pseudo second order model with good correlation and the adsorption rate constant ($k^2$) decreased with increasing initial concentration. Thermodynamic parameters like activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption in the temperature range of 298~318 K. The activation energy was determined as 23.90 kJ/mol. It was found that the adsortpion of metanil yellow on the granular activated carbon was physical process. The negative Gibbs free energy change (${\Delta}G=-2.16{\sim}-6.55kJ/mol$) and the positive enthalpy change (${\Delta}H=+23.29kJ/mol$) indicated the spontaneous and endothermic nature of the adsorption process, respectively.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.25-32
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• 2009

The main objective of this study was to examine the removal properties of Cu from water by inflated vermiculites. The component of vermiculites was analyzed by XRF and the concentration of Copper ion was measured by UV-VIS. Serial batch Kinetic tests and batch sorption tests were conducted to determine the removal characteristics for Cu in aqueous solutions. The result shows that removal rate, $K_{obs}$, of Cu are 0.73, 1.52, and 1.71 for initial pH 3, pH 4, pH 5, respectively, and are 3.19, 1.90, and 0.73 for the initial concentration of $1mg\;L^{-1}$, $5mg\;L^{-1}$, $10mg\;L^{-1}$, respectively. It leads to the conclusion that the removal rates are inversely proportional to the initial Cu concentration and are increased proportionally to the initial pHs. Finally, Sorption data were correlated with both Langmuir and Freundlich isotherms. As a result, Langmuir and Freundlich models were well fitted to batch isotherm data with good values of the determination coefficient. but the determination coefficient value for the Freundlich model fit was slightly higher than that of Langmuir model (0.965 for the Freundlich model and 0.936 for the Langmuir model). Using the Langmuir model, the maximum sorption capacity ($Q_{max}$), Freundlich partition coefficient, and the numerical value of n wrer estimated as $1,250mg\;kg^{-1}$, $635.1L\;kg^{-1}$ and 1.69, respectively. These results show that the inflated vermiculites could be used as an excellent adsorbent for copper contained in various types of aqueous solutions.

• Journal of the Korean Geotechnical Society
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• v.27 no.4
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• pp.43-50
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• 2011

Steel-making slag was investigated as reactive material for removal of cadmium in coastal area. Batch experiments of the sorption isotherm experiment and kinetic sorption experiment were performed. Result of sorption isotherm was more adequately described by Langmuir model than Freundlich model and theoretical maximum capacity (${\beta}$) of cadmium onto steel-making slag was found. Results of kinetic sorption experiments were evaluated by pseudo second order model to investigate sorption characteristics of cadmium onto steel-making slag. Results showed that the equilibrium sorption amount of cadmium (q$q_e$) increased and the rate constant ($k_2$) and initial sorption rate (h) decreased as the initial cadmium concentration increased. The $q_e$ with simulated sea water was similar to that with deionized water and $k_2$ and h with simulated sea water was lower than those with deionized water. Results of kinetic experiments could be used to predict the result from sorption isotherm, since equilibrium sorption amounts calculated by pseudo second order model generally agreed with those measured from sorption isotherm. The reaction time for the target removal rate could be calculated by the pseudo second order model using kinetic sorption tests results.

• 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.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.