• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.526-531
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• 2020

Manganese ions contained in water phase are acting as a toxic substance in the human body and also known to affect the nervous system. In particular, effective treatment technology is required since manganese removal is difficult due to its high solubility in a wide pH range. In this study, Prinus densiflora bark was chemically modified with hydrogen peroxide, and the modified adsorbent was used for removing manganese ions in an aqueous solution. The modified adsorbent showed high removal capacity of 82.1 and 56.2%, respectively, at conditions of 5 and 10 mg/L manganese ions. Also, the adsorption isotherm from the data was applied to the theoretical equation. As a result, the adsorption behavior of manganese ions was better suited to the Langmuir than Freundlich model, and it was also found from kinematics that the pseudo-second order kinetic model was more suitable. In addition, the changes of Gibbs free energy indicated that the adsorption reaction became more spontaneously with increasing temperature. Consequently, these experimental results may be used as a water treatment technology which can efficiently treat manganese ions contained in water.

• Environmental Engineering Research
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• v.14 no.1
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• pp.26-31
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• 2009

Sorption of $Ni^{2+}$ in aqueous solution was studied using montmorillonite. The experimental and equilibrium data fitted well to the Langmuir isotherm model. From the kinetics data for nickel sorption onto montmorillonite, the diffusion of $Ni^{2+}$ inside the clay particles was the dorminant step controlling the sorption rate and as such more important for $Ni^{2+}$ sorption than the external mass transfer. $Ni^{2+}$ was sorbed due to strong interactions with the active sites of the sorbent and the sorption process tends to follow the pseudo second-order kinetics. Thermodynamic parameters (${\Delta}G^{\circ},\;{\Delta}H^{\circ},\;{\Delta}S^{\circ}$) indicated a non spontaneous and endothermic adsorption process while the positive low value of the entropy change suggests low randomness of the solid/solution interface during the uptake of $Ni^{2+}$ by montmorilionite. Heavy metals such as $Ni^{2+}$ in aqueous bodies can effectively be sorbed by montmorillonite.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.389-395
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• 2006

The use of pine bark, a natural adsorbent prepared from Korean Red Pine (Pinus densifloral), was studied for its adsorption behavior of lead ion from aqueous solution. Adsorption experiments were carried out on lead ion concentrations of 10mg/L. Adsorption of lead ion could be described by both Langmuir and Freundlich adsorption isotherms. Treatment of the bark with nitric acid greatly increased initial adsorption rate, and equilibrium sorption capacity increased by approximately 48%. A pseudo second-order kinetic model fitted well for the kinetic behavior of lead ion adsorption onto the bark. Acid-treated bark demonstrated its adsorption capacity quite close to that of granular activated carbon. Results of this study indicated that ion exchange and chelation were involved in the adsorption process.

• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.370-374
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• 2009

Adsorption characteristics of glass fibers, obtained from the spent lithium primary batteries recycling process, were investigated for the removal of Acid Red 27 dye from aqueous solution. The batch data clearly showed that increasing the initial sorptive concentration apparently enhanced the amount adsorbed and the uptake process followed the pseudo-second order rate model. The equilibrium adsorption data at different initial sorptive concentrations were fitted well to Freundlich and Langmuir adsorption isotherms. Moreover, the increase in temperature, favored the uptake of dye on this solid, indicated the process was endothermic in nature. Further, using the temperature dependence sorption data obtained at different temperatures was used to estimate various thermodynamic parameters.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.503-508
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• 2015

The adsorption characteristics of ammonia on MSWI bottom ash were investigated. The effect of the variation of the landfill environmental parameters including pH, anions and organic matter on the adsorption process was discussed. Results showed that the adsorption could be well described by pseudo-second-order kinetics and Langmuir model, with a maximum adsorption capacity of 156.2 mg/g. The optimum adsorption of ammonia was observed when the pH was 6.0. High level of ion and organic matter could restrict the adsorption to a low level. The above results suggested that MSWI bottom ash could affect the migration of ammonia in the landfill, which is related to the variation of the landfill circumstance.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.143-152
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• 2018

The process parameters of ethyl violet from aqueous solution by activated carbon adsorption were carried out as a function of pH, temperature, contact time, initial concentration and temperature. The adsorption equilibrium data can be described well by the Langmuir and Freundlich isotherm models. Base on Langmuir constant ($R_L=0.0343{\sim}0.0523$) and Freundlich constant (1/n=0.1633~0.1974), This process could be employed as effective treatment for adsorption of ethyl violet. The kinetic experimental results showed that the adsorption process can be well described with the pseudo second order model. Based on the positive enthalpy (6.505 kJ/mol), the adsorption of ethyl violet onto granular activated carbon is endothermic. The negative Gibbs free energy (-1.169~-1.681 kJ/mol) obtained indicates that the adsorption process is spontaneous and physisorption.

• 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.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.1-7
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• 2015

The solid-phase extractant PS-D2EHPA/TBP was prepared by immobilizing two extractants D2EHPA and TBP in polysulfone (PS). The prepared PS-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal of Cu(II) from aqueous solution was investigated in batch system. The experiment data were obeyed the pseudo-second-order kinetic model. Equilibrium data were well fitted by Langmuir model and the removal capacity of Cu(II) by solid extractant PS-D2EHPA/TBP obtained from Langmuir model was 3.11 mg/g at 288 K. The removal capacity of Cu(II) was increased according to increasing pH from 2 to 6, but the removal capacity was decreased below pH 3 remarkably.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.841-849
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• 2015

The solid phase extractant SAN-D2EHPA/TBP containing two extractants of Di-(2-ethylhexyl)phosphoric acid (D2EHPA) and Tri-butyl-phosphate (TBP) was prepared by immobilizing two exractants D2EHPA and TBP in styrene acrylonitrile copolymer (SAN). The prepared SAN-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The solid phase extractant SAN-D2EHPA/TBP was tested for the removal of Cu(II) from aqueous solution. Experiments were carried out as a function of the pH and Cu(II) concentration in the aqueous phase. The equilibrium time was 180 min and equilibrium experiment data obeyed the pseudo-second-order kinetic model. The Langmuir isotherm model represented the experiment data as well. The maximum removal capacity of Cu(II) calculated from Langmuir isotherm model was 3.1 mg/g.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.27-36
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• 2007

Milled Korean pine (Pinus densiflora) wood was used to evaluate its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled woods were pretreated with 1N NaOH, 1N $NHO_3$, and distilled water, respectively, to examine the effect of pretreatment. Within the tested pH range in this study between 3 and 6, copper adsorption efficiency of NaOH-treated wood(96~99%) was superior than $NHO_3$-treated wood(19~31%) and distilled water-treated wood(18~35%). Adsorption behavior of copper onto both raw and $NHO_3$-treated woods was mainly attributed to interaction with carboxylic acid group. For NaOH-treated wood, carboxylate ion produced by hydrolysis was a major functional group responsible for Cu sorption. NaOH treatment of wood changed the ester and carboxylic acid groups into carboxylate group, whereas $NHO_3$ treatment did not affect the production of functional groups which could bind copper. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto NaOH-treated wood. A batch isotherm test using NaOH-treated wood showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model.