• Clean Technology
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• v.25 no.1
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• pp.56-62
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• 2019

The equilibrium, kinetic and thermodynamic parameters of adsorption of murexide by granular activated carbon were investigated. The experiment was carried out by batch experiment with the variables of the amount of the adsorbent, the initial concentration of the dye, the contact time and the temperature. The isothermal adsorption equilibrium was best applied to the Freundlich equation in the range of 293 ~ 313 K. From the separation factor (${\beta}$) of Freundlich equation, it was found that adsorption of murexide by granular activated carbon could be the appropriate treatment method. The adsorption energy (E) obtained from the Dubinin- Radushkevich equation shows that the adsorption process is a physical adsorption process. From the kinetic analysis of the adsorption process, pseudo second order model is more consistent than pseudo first order model. It was found that the adsorption process proceeded to a spontaneous process and an endothermic process through Gibbs free energy change ($-0.1096{\sim}-10.5348kJ\;mol^{-1}$) and enthalpy change ($+151.29kJ\;mol^{-1}$). In addition, since the Gibbs free energy change decreased with increasing temperature, adsorption reaction of murexide by granular activated carbon increased spontaneously with increasing temperature. The entropy change ($147.62J\;mol^{-1}\;K^{-1}$) represented the increasing of randomness at the solid-solution interface during the adsorption reaction of murexide by activated carbon.

• Applied Biological Chemistry
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• v.15 no.3
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• pp.229-240
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• 1972

Not only in order to determine reasonable application amounts of PCP in terms of soil texture, but also to get basic data for fish-toxicity-free treatment by estimating fish toxicity, some aspects of PCP adsorption were observed taking various paddy soils with different physico-chemical characteristics in the Choongbook Area as samples. The results obtained are summarized as follows: 1. There was a positive correlation between PCP adsorption and clay contents, total nitrogen, organic matter, cation exchange capacity, exchangeable bases, and phosphorus absorption coefficients, respectively; whereas there was a negative one between PCP adsorption and pH. Although they were not significant, it was remarkable that there was a relatively large amount of correlation between PCP adsorption and clay contents, $H^+,\;Mg^{++}$, and CEC, respectively. 2. PCP adsorption in terms of soil texture was in the order of Clay>Loam>Sandy loam. 3. Although PCP adsorption in the $H_2O_2-treated$ soils decreased remarkably, it was not proportional to the humus contents. 4. The order of PCP adsorption in the exchangeable base-treated soils was H^+-exchanged soil>$K^+-soil$>$Na^+-soil$>$Ca^{++}-soil$>Mg^{++}-soil. 5. Langmuir's and Freundlich's adsorption isotherms were applicable to the PCP adsorption, and thereby were able to be calculated maximum adsortion amounts of PCP, bond energy, and the depths of adsorption layers. 6. Maximum adsorbed amounts of PCP were 212.14 mg/100gr in Clayey loam, 97.28 to 121.59mg/100gr in Loam, and 32.92 to 91.74mg/100gr in Sandy loam, respectively. 7. The depths of mixed layers of limiting application for fish-toxicity-free treatment were 0.88cm of the Jinchun soil, the shallowest and 4.29 cm of the Naesan-ri Sandy loam, the deepest.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.218-222
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• 1998

Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.746-752
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• 1993

Quantitative measurements have been made by using equilibrium dialysis techniques on the extent of complexation between PCB and dissoved humic acid(HA). This research investigates the effectiveness of activated carbon adsorption for the removal of PCB from organic free water and humid acid background solution by using bench-scale equilibrium and rate tests. It was found that the extent of complexation depended on the pH, calcium concentration, ionic strength, and the concentration of humic acid. When HA was present, activated carbon capacity was greatly reduced due to complexation and competitive adsorption effects and the adsorption characteristics became complicated by the presence of various species such as the unassociated HA, PCB, and PCB-HA complexes.

• Analytical Science and Technology
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• v.12 no.2
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• pp.159-165
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• 1999

The adsorption and separation behaviors of transition metal ions using a merrifield resin bound 1,12-diaza-3,4:9,10-dibenzo-5,8-dioxacyclopentadecane (NTOE) and 1,12,15-triaza-3,4:9,10-dibenzo-5,8-dioxacycloheptadecane(NDOE) were investigated in aqueous solution. The orders of adsorption degree(E) and distribution ratio(D) of transition metal ions were Cu(II)$t_R$) of metal ions were affected by adsorption degree(E) and distribution ratio(D). This results showed good separation efficiency of Ag(I) from mixed metal solution.

• Clean Technology
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• v.26 no.3
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• pp.186-195
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• 2020

The isothermal adsorption, dynamic, and thermodynamic parameters of Acid black (AB) and Quinoline yellow (QY) adsorption by activated carbon were investigated using the initial concentration, contact time, temperature, and pH of the dyes as adsorption parameters. The adsorption equilibrium data fits the Freundlich isothermal adsorption model, and the calculated Freundlich separation factor values found that activated carbon can effectively remove AB and QY. Comparing the kinetic data showed that the pseudo second order model was within 10% error in the adsorption process. The intraparticle diffusion equation results were divided into two straight lines. Since the slope of the intraparticle diffusion line was smaller than the slope of the boundary layer diffusion line, it was confirmed that intraparticle diffusion was the rate-controlling step. The thermodynamic experiments indicated that the activation energies of AB and QY were 19.87 kJ mol^-1 and 14.17 kJ mol^-1, which corresponded with the physical adsorption process (5 ~ 40 kJ mol^-1). The adsorption reaction was spontaneous because the free energy change in the adsorption of AB and QY by activated carbon was negative from 298 to 318 K. As the temperature increased, the free energy value decreased resulting in higher spontaneity. Adsorption of AB and QY by activated carbon showed the highest adsorption removal rate at pH 3 due to the effect of anions generated by dissociation. The adsorption mechanism was electrostatic attraction.

• 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.27 no.6
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• pp.590-598
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• 2016

In this study, the adsorption behavior from aqueous solution as well as kinetic and thermodynamic parameters of Acid Black 1 were investigated through batch reaction using coconut shell based granular steam activated carbon. The effects of various adsorption parameters such as pH, initial concentration, contact time, temperature were studied. To confirm the effect of pH, pHpzc measurements were analyzed followed by measuring removal efficiencies of Acid Black 1 at the pH range from 3 to 11. Experimental equilibrium adsorption data were fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption isotherm. The conformity of adsorption reaction for pseudo first and second order model were evaluated through kinetic analysis. Values of enthalpy change and activation energy were also investigated through thermodynamic analysis and it was confirmed that the adsorption process was endothermic. The spontaneity of adsorption process was evaluated using the values of entropy and Gibbs free energy changes.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.190-197
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• 2019

The adsorption of methyl green dye using an activated carbon from an aqueous solution was investigated. Adsorption experiments were carried out as a function of the adsorbent dose, initial concentration, contact time and temperature. The Langmuir isotherm model showed a good fit to the equilibrium adsorption data. Based on the estimated Langmuir separation factor, ($R_L=0.02{\sim}0.106$), this process could be employed as the effective treatment (0 < $R_L$ < 1). It was found that the adsorption was a physical process with the adsorption energy (E) value range between 316.869 and 340.049 J/mol obtained using Dubinin-Radushkevich equation. The isothermal saturation capacity obtained from brunauer emmett teller (BET) model increased with increasing the temperature. The kinetics of adsorption followed a pseudo second order model. The free energy and enthalphy values of -5.421~-7.889 and 31.915 kJ/mol, respectively indicated that the adsorption process follows spontaneous endothermic reaction. The isosteric heat of adsorption increased with the increase of equilibrium adsorption amounts, and the total interaction of the adsorbent - adsorbate increased as the surface coverage increased.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2471-2476
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• 2014

The aim of the present study is to explore the possibility of utilizing loess for the adsorption of total phosphorous (T-P) and total nitrogen (T-N) in water. Batch adsorption studies were performed to evaluate the influences of various factors like initial concentration, contact time and temperature on the adsorption of T-P and T-N. The adsorption data showed that loess is not effective for the adsorption of T-N. However, loess exhibited much higher adsorption capacity for T-P. At concentration of $1.0mgL^{-1}$, approximately 97% of T-P adsorption was achieved by loess. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher $R^2$ compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium $q_{e,cal}$ from pseudo-second-order kinetic model was relatively similar to the experimental adsorption equilibrium $q_{e,exp}$. The thermodynamic parameters such as free energy ${\Delta}G$, the enthalpy ${\Delta}H$ and the entropy ${\Delta}S$ were also calculated.