• 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.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.659-667
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• 2006

This research aims at applicability of adsorption process in order to satisfy the restricted Effluent Quality Standards for dyeing wastewater. The dyeing wastewater treated by biological process with carrier imbedded microorganisms was directly applied to the activated carbon adsorption in Process A, The dyeing wastewater treated by Fenton oxidation for the effluent of biological process was applied to the adsorption in Process B. It was found that the optimum conditions of adsorption with granular activated carbon are $20^{\circ}C$ and 120 minutes for the batch experiment. Langmuir equation was fitted better than Freundlich equation to the experimental data. The breakthrough time of adsorption column was determined by color rather than $COD_{Mn}$ for both Process A and Process B. The results revealed that the breakthrough time of adsorption for two processes was extended by the treatment of Fenton oxidation for dyeing wastewater treated by biological treatment than the direct application of dyeing wastewater treated by the biological treatment. Adsorption process can be applied in order to meet the restricted Effluent Quality Standards for dyeing wastewater.

• Journal of Hydrogen and New Energy
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• v.32 no.4
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• pp.197-204
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• 2021

Pressure swing adsorption is a purification process which can get pure hydrogen. The purification process is composed of four process: compression, adsorption, desorption and discharge. In this study the adsorption process was simulated by using the Fluent and validated with experimental results. A gas used in experiment is composed of H₂, CO₂, CH₄, and CO. Adsorption process conducted under 313 kelvin and 3 bar and bituminous-coal-based (BPL) activated carbon was used as the adsorbent. Langmuir model was applied to explain the gas adsorption. And diffusion of all the gases was controlled by micro-pore resistances. The result shows that, the most adsorbed gas was carbon dioxide, followed by methane and carbon monoxide. And carbon monoxide took the least amount of time to reach the maximum adsorption amount. The molar fraction of the off-gas became the same as the molar fraction of the gas supplied from the inlet after adsorption reached the equilibrium.

• Clean Technology
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• v.20 no.3
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• pp.290-297
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• 2014

Batch adsorption studies were carried out for equilibrium, kinetics and thermodynamic parameters for adsorption of coomassi brilliant blue G (CBBG) using activated carbon with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich and Dubinin-Radushkevich isotherms. From estimated separation factor of Langmuir and Freundlich, this process could be employed as effective treatment for removal of CBBG. Also from Dubinin-Radushkevich isotherm model, adsorption energy (E) indicated adsorption process is physical adsorption. From kinetic experiments, the adsorption reaction was found to confirm to the pseudo second order model with good correlation. Intraparticle diffusion was rate controlling step. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (406.12 kJ/mol) indicated endothermic nature of the adsorption process. The change of entropy (1.66 kJ/mol K) showed increasing disorder in process. The change of free energy found that the spontaneity of process increased with increasing adsorption temperature.

• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.89-96
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• 2017

This study proposed adsorption of Pb(II) ions from aqueous solution using activated carbon prepared from areca catechu shell (ACS AC) using Timphan Method. The effects of independent variables on adsorption kinetic and isotherm have been investigated by conducting experiments in batch mode at neutral pH. The structural characterization of adsorbent was done by FT-IR and SEM analysis. The Pb(II) adsorption was correlated very well with the pseudo second-order kinetic (PSOKM) and Langmuir isotherm models (LIM). Increasing NaOH mass for activation and adsorption temperature increased weakly all the parameters of adsorption kinetic and isotherm. The Pb(II) ions adsorption capacity of the ACS AC at 27 and $45^{\circ}C$ was 50.51 and 55.25 mg/g, respectively. Thermodynamic parameters were determined, and the results confirmed the Pb(II) ions adsorption should be endothermic and spontaneous process, and both physical and chemical adsorption should be taken place.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.1-8
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• 1999

This study was aimed ultimately to develop an adsorption process treating heavy metal wastewater by utilizing activated carbon using flyash. The affecting factors in adsorption process on heavy metal by flyash adhesion-activated carbon are s follows. Factors such as pH, and quality of activated carbon, and reaction time made batch adsorption isotherm described adsorption capacity was made use of the investigation to evaluate adsorptive possibility of heavy metal.As the results of this study, H ion has influence on adsorption of heavy metal if pH is low. As reaction time is transformed, factors such as optimum reaction time is taken into consideration an adsorptive process of heavy metal because an adsorption and a reduction process occur. Adsorption isotherm of adhesion-activated carbon was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, l/n were obtained in the range of 0.1~0.5.

• Environmental Engineering Research
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• v.20 no.2
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• pp.181-189
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• 2015

A composite material was tested to eliminate phenol in aqueous solution combining adsorption on activated carbon and photocatalysis with $TiO_2$ in two different ways. A first implementation involved a sequential process with a loop reactor. The aim was to reuse this material as adsorbent several times with in situ photocatalytic regeneration. This process alternated a step of adsorption in the dark and a step of photocatalytic oxidation under UV irradiation with or without $H_2O_2$. Without $H_2O_2$, the composite material was poorly regenerated due to the accumulation of phenol and intermediates in the solution and on $TiO_2$ particles. In presence of $H_2O_2$, the regeneration of the composite material was clearly enhanced. After five consecutive adsorption runs, the amount of eliminated phenol was twice the maximum adsorption capacity. The phenol degradation could be described by a pseudo first-order kinetic model where constants were much higher with $H_2O_2$ (about tenfold) due to additional ${\bullet}OH$ radicals. The second implementation was in a continuous process as with a fixed bed reactor where adsorption and photocatalysis occurred simultaneously. The results were promising as a steady state was reached indicating stabilized behavior for both adsorption and photocatalysis.

• Journal of Environmental Science International
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• v.21 no.5
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• pp.623-631
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• 2012

The adsorption behavior of Eosin Y on activated carbon (AC) in batch system was investigated. The adsorption isotherm could be well fitted by the Langmuir adsorption equation. The kinetics of adsorption followed the pseudo-second-order model. The temperature variation was used to evaluate the values of free energy (${\Delta}G^{\circ}$), enthalpy (${\Delta}H^{\circ}$) and entropy (${\Delta}S^{\circ}$). The positive value of enthalpy change ${\Delta}H^{\circ}$ for the process confirms the endothermic nature of the process and more favourable at higher temperature, the positive entropy of adsorption ${\Delta}S^{\circ}$ reflects the affinity of the AC material toward Eosin Y and the negative free energy values ${\Delta}G^{\circ}$ indicate that the adsorption process is spontaneous. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size.

• Polymer(Korea)
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• v.26 no.5
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• pp.551-558
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• 2002

It was observed that adsorption characteristics of sulfonated fabric ion-exchanger for separating nickel ion from electroplating rinse water. Swelling ratio was increased by increasing degree of sulfonation and polarity of solvent. Ion-exchange capacity was also increased by increasing degree of sulfonation and showed 3.38 meq/g at 16% sulfonated ion-exchanger. There was little effects of pH. Adsorption equilibrium was attained within 10 min, and adsorption rate was 7.5 mg/min. Adsorption capacity was not changed after 7 cycles of regeneration process. Regeneration adsorption capacity was slightly decreased to 2.01 meq/g. It confirmed that durability of sulfonated fabric ion-exchanger was suitable for adsorption process. Adsorption equilibrium time was linearly increased by increasing L/D and adsorption capacity showed the ion exchange capacity within the range of 2.71 ∼ 3.01 meq/g in continuous process. Design of adsorption column could be possible for L/D<2. Under constant L/D condition, there is no little pH effect when rinse water is acidic solution, and operation condition of adsorption process was optimized under pH 5.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.447-450
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• 2006

Hydrogen separation from multi-component mixture gases by the four-bed PSA process was studied experimentally and theoretically using layered bed of activated carbon and zeolited 5A. Effects of the adsorption time, the linear velocity on the process performance were investigated. The adsorption time and linear velocity affected the purity and recovery of the product $H_2$ purity is increases according as the adsorption time and linear velocity decrease; however, $H_2$ recovery shows an opposite phenomena to the purity. PSA process simulation studied to find optimum operation condition. In the results, 50sec adsorption time, 3cm/s linear velocity might be optimal values to obtain more than 99.999% purity and 65% recovery hydrogen.