• Journal of Energy Engineering
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• v.13 no.2
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• pp.166-172
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• 2004

The activated carbon was produced from Sancheong bamboo by steam and carbon dioxide gas activation methods. The carbonization of raw material was conducted at 90$0^{\circ}C$ and gas activation reactions were conducted with respect to various conditions. -activation temperature 750-90$0^{\circ}C$, the flow rate of steam 0.5-2g-$H_2O$/g-char$.$hr, the flow rate of carbon dioxide 5-30$m\ell$-$CO_2$/g-char-min and activation time 1-5 hr. The prepared activated carbons were measured yield, the adsorption capacity of iodine and methylene blue, BET specific surface area and pore size distribution. The adsorption capacity of iodine (680.5-1526.1 mg/g) and methylene blue (18.3-221.5 mg/g) increased with creasing activation temperature and activation time. The adsorption capacity of iodine and methylene blue increased with the activation gas quantity in the range of 0.5-1.5g-$H_2O$/g-charㆍhr, 5-18.9$m\ell$-Co$_2$/g-charㆍmin. But those decreased over those range due to the pore shrinkage. The steam activation method was superior in efficiency to carbon dioxide activation method.

• Journal of Environmental Science International
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• v.13 no.7
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• pp.661-665
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• 2004

As the concentration of ammonium nitrogen could be reached 2～3 mg/L in the winter in the river. It was clear that the excessive concentration of chlorinated organics could be produced with the increase of chlorine addition to remove ammonium nitrogen. In the innovative ammonium nitrogen removal process, zeolite adsorption is very efficient as substitute for rapid sand filtration without other adverse quality change in the water. This study is conducted to evaluate the feasibility of ammonium nitrogen removal and regeneration by zeolite adsorption in drinking water treatment. Also, the reuse possibility of zeolite is evaluated to change the removal efficiency of ammonium nitrogen through several times of regeneration. The ammonium nitrogen was not removed in sand filter, but it was almost removed in zeolite filter during 7 days. The sand and zeolite filters have a similar result of turbidity removal. Therefore, zeolite filtration was confirmed the removal of turbidity and ammonium nitrogen as a media. When compared KCl with NaCl as a chemical for zeolite regeneration, it is demonstrated that KCl was more efficient than NaCl in the ability of zeolite regeneration. The adsorption rate of ammonium nitrogen was almost not decreased in the results of several times of regeneration. It is indicated that both zeolite and regeneration solution were possible to reuse without variation of regeneration rate through this study.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.47-52
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• 2008

In this study, GAC adsorption, ozonation and $O_3/GAC$ hybrid processes were investigated for treatment of humic acid. The degradation characteristics and efficiencies of humic acid in each process were evaluated through pH variation, $UV_{254}$ decrease, DOC removal, change of molecular size distribution and by-products formation. DOC removal rate in $O_3/GAC$ hybrid process (80%) was higher than arithmetic sum of ozonation (38%) and GAC adsorption process (19%) by synergism. $UV_{254}$ decrease rate of humic acid was also the highest than any other processes when treated in $O_3/GAC$ hybrid process. Molecular size distribution was not significantly changed in the GAC adsorption process. Main distribution of molecular size of humic acid was converted from 3 k~30 kDa into 0.5 k~3 kDa in ozonation. But the most of large molecular sizes of humic acid converted into small molecules(smaller than 0.5 kDa) in $O_3/GAC$ hybrid process. Quantities of formaldehyde and glyoxal formed in $O_3/GAC$ hybrid process were less than the ones in ozonation.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.39-53
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• 2016

In this study, polysufone (PSf) was used as a base polymer to synthesize sulfonated polysulfone (SPSf) and aminated polysulfone (APSf) as cation and anion exchange polymers, respectively. Then the ion exchange polymers were coated onto the surface of commercial carbon electrodes. To compare the capacitive deionization (CDI) and membrane capacitive deionization (MCDI) processes, the pristine carbon electrodes and ionic polymer coated electrodes were tested under various operating conditions such as feed flow rate, adsorption time at fixed desorption time, and feed concentration, etc., in terms of effluent concentration and salt removal efficiency. The MCDI was confirmed to be superior to the CDI process. The performance of MCDI was 2-3 times higher than that of CDI. In particular, the reverse desorption potential was a lot better than zero potential. Typically, the salt removal efficiency 100% for 100 mg/L NaCl was obtained for MCDI at feed flow rate of 15 ml/min and adsorption/desorption time of 3 min/1 min and applied voltages 1.0 V for adsorption and -0.3 V for desorption process, and for 500 mg/L, the salt removal efficiency 91% was observed.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.36-41
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• 2004

The breakthrough curve was obtained to evaluate separation efficiency of clinoptilolite as an methane/nitrogen separation adsorbent. The Ca-exchanged clinoptilolite showed improved separation efficiency. The nitrogen adsorption capacity of Ca-clinoptilolite was increased with decreasing temperature. The temperature was decreased from 293K to 253K(feed gas flow rate : 670ml/min, pressure : 333kPa). The adsorption capacity is increased with increasing pressure. The pressure was increased from 333kPa to 700kPa(feed gas flow rate : 670ml/min, temperature : 253K, 293K).

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.423-432
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• 2022

Magnetic biochar produced from pyrolysis of dairy cattle manure was used to develop an effective sorbent for arsenic purification from aqueous solution. Biomass and magnetized biomass were pyrolyzed in a tube furnace with 10 ℃/min heating rate at 450 ℃ under nitrogen flow of 100 cm³/min for 2 h. Biochars were characterized by SEM-EDX, BET, XDR, FTIR, TGA, zeta potential analysis. The resultant biochar and magnetic biochar were opposed to 50-100-500 ppm As(V) laden aqueous solution. Adsorption experiments were performed by using ASTM 4646-03 batch method. The effects of concentration, pH, temperature and stirring rate on adsorption were evaluated. As(V) was successfully removed from aqueous solution by magnetic biochar due to its highly porous structure, high aromaticity and polarity. The results suggest dairy cattle manure pyrolysis is a promising route for managing animal manure and producing a cost effective biosorbent for efficient immobilization of arsenic in aqueous solutions.

• Journal of Wetlands Research
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• v.26 no.3
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• pp.272-278
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• 2024

Due to industrialization, a trace amount of residues of pharmaceuticals and personal hygiene products (PPCPs) flows into the ecosystem, polluting the ecosystem. In particular, it was intended to remove trace pollutants flowing into the effluent due to the increase in the amount of acetaminophen detected after COVID 19. To conduct this experiment, selected 6 media which are suitable for construcgted wetland and isothermal adsorption experiments. Langmuir equation and the Freundlich equation were used to calculate the maximum removal rate of acetaminophen. Among them, the Freundlich equation showed a higher result value of 0.9823. It was applied when forming constructed wetlands in urban areas to model the reduction rate of acetaminophen in wetlands.

• 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.26 no.2
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• pp.122-130
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• 2020

The isotherm, kinetic, and thermodynamic parameters of reactive blue 4 adsorbed by activated carbon were investigated for activated carbon dose, pH, initial concentration, contact time, and temperature data. The adsorption of the RB 4 dye by activated carbon showed a concave shape in which the percentage of adsorption increased in both directions starting from pH 7. The isothermal adsorption data were applied to Langmuir, Freundlich, and Temkin isotherms. Both Freundlich and Langmuir isothermal adsorption models fit well. From determined Freundlich separation factor (1/n = 0.125 ~ 0.232) and Langmuir separation factor (R_L = 1.53 ~ 1.59), adsorption of RB 4 by activated carbon could be employed as an effective treatment method. The constant related to the adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) of Temkin 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 model showed that the inclination of the first straight line representing the surface diffusion was smaller than that of the second straight line representing the intraparticle pore diffusion. Therefore, it was confirmed that intraparticle pore diffusion is the rate-controlling step. The negative Gibbs free energy change (ΔG = -3.262 ~ -7.581 kJ mol^-1) and the positive enthalpy change (ΔH = 61.08 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, proving this process to be spontaneous and endothermic.

• 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.