• Journal of Environmental Science International
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• v.8 no.3
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• pp.399-409
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• 1999

The three domestic natural zeolites(Yong dong-ri (Y), Daesin-ri (D), Seogdong-ri (S)) harvested in Kyeongju-shi and Pohang-shi, Kyungsangbug-Do, were pretreatd with each of the NaOH, $Ca(OH)_2$ and NaOH following HCl solutions, and the removal performances of divalent haevy metals(Cu, Mn, Pb, and Sr) for natural and pretreated zeolites were investigated and compared in the single and mixed solutions. The natural zeolite-heavy metal system attained the final equilibrium plateau within 20 min, irrespective of initial heavy metal concentration. The heavy metal uptakes increased with increasing initial heavy metal concentration and pH. The heavy metal uptakes for natural zeolites decreased in the following sequences : D>Y>S among the natural zeolites; Pb>Cu>Sr>Mn among the heavy metals. The pretreated zeolites showed higher heavy metal removal performances than natural zeolites and decreased in the order of NaOH, NaOH following HCl, $Ca(OH)_2$ treatment among the pretreatment methods. The heavy metal ion exchange capacity by natural and pretreated zeolites was described either by Freundlich equation or Langmuir equation, but it followed the former better than the latter. The heavy metal uptakes for natural zeolites decreased in the mixed solution, in comparing with those in the single solution and especially, the manganese uptake decreased greatly in the mixed solution. The pretreated zeolites showed the improved removal performances of heavy metals in the mixed solution than in the single solution and the heavy metal uptakes by those in the mixed solution showed the same trends in the single solution among the chemical treatment methods and heavy metals.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.41-47
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• 1998

The purpose of this research is evaluation of adsorption capacity of the cast for TCE comparing with the yellow clay. Furthermore, the experimental data was fitted with the Langmuir and Freundlich isotherm and was found to be apllicable to the adsorption isotherm equation. The soil bed reactor used in this study was made of glass(10 cm in diameter, 100 cm in depth). The cast and yellow clay used as adsorbents were screened with 8-20 mesh mecanically. Results from Equilibrium test with adsorbents showed that the equibrium time of the cast and yellow clay was 9min independent of the amount of the adsorbents. The adsorption efficiencys of the cast and yellow clay for TCE was 66.3% and 56.2%, respectively. In the application of Freundlich isotherm, 1/n of the cast and yellow clay were 0.786 and 0.704, respectively. These results showed that the cast was more available than the yellow clay as TCE adsorbent. The best adsorption capacity was showed at 0% moisture content, 70 ppm inlet concentration and 25$^{\circ}$C temperature.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.531-539
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• 1997

Lead sorption performances by biomass of nonliving, dried marine brown algae Undaria phnaunda, Hlzikia hsyormls. and Sugassum fulvellum used as biosorbent materials were investigated. As the amount of biosorbent materials added was increased, the lead removal by biosorbent materials Increased but the lead biosorption capacities decreased. However, with increasing Initial lead concentration the lead biosorption capacities by the biosorbent materials Increased but lead removal efficiencies decreased. In the range of Initial lead concentration(Co) 10-500 mg/L the lead biosorption capacities and removal efficiencies by the biosorbent materials Increased with increasing pH. Among the biosorbent materials used in this study, the lead biosorption capacities decreased in the following sequence: U. plilnaunda > H. fusiformis > S. fulvellum. The lead biosorption by biosorbent materials were expressed by the Langmuir Isotherm better than the Freundlich Isotherm. The biosorption rate could be expressed by the first order reaction rate equation for initial lead concentration like that rad : 0.288Co for U. phanda, rad = 0.255Co for H. fusiformis, and rad : 0.161Co for S. fulvellum. Key words : Lead, biosorption, biosorbent, Undaria pinnatinda, Hiztkia fusiformis, Sargassum fulvellum, Langmuir isotherm, Freundlich isotherm, biosorption rate.

• Journal of environmental and Sanitary engineering
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• v.19 no.1
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• pp.37-41
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• 2004

The removal efficiency of cadmium by chitosan complex isolated from Aspersillus oryzae was investigated through laboratory experiments. The results of the study are as follows. The adsorption kinetics of cadmium was reached the adsorption equilibrium in approximately 20 minutes and the removal efficiency was showed 95.8%. The effect of temperature on cadmium adsorption by chitosan complex shows that as the temperature increased, the amount of cadmium adsorption per unit weight of chitosan complex increased. The correlation between amount of cadmium adsorption per unit weight of chitosan complex and temperature was obtained through the coefficient of determination($R^2$). $R^2$ values was 0.854(p<0.05). A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constant, the adsorption intensity(1/n) was 0.550, and the measure of adsorption(k) was 2.181. So, it was concluded that adsorption of cadmium by chitosan complex is effective.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.59-64
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• 2006

In this study, adsorption characteristics of PCBs on granular activated carbon were experimentally investigated in a batch reactor and in a fixed bed reactor. Granular activated carbon removed above 98.4% of initial concentration, 1000mg/L, of PCBs. It was estabilished that the adsorption equilibrium of PCBs on granular activated carbon was more successfully fitted by Freundlich isotherm equation in the concentration range from 1 to 1000mg/L. Because Freundlich parameter, ${\beta}$ is 0.346, removall treatment of PCBs by activated carbon accounts for the fact that toxicity reduction can be achieved through this process. Appearance time of breakthrough curve is faster with the increase flow rate and inflow concentration of liquid. The utility of granular activated carbon is enhanced with the increase of bed height and with the decrease of inflow rate.

• Environmental Engineering Research
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• v.10 no.2
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• pp.45-53
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• 2005

Metal oxide particles with mole ratio of aluminum: titanium of 1:1 were synthesized by a sol-gel method. Langmuir (a) and Freundlich (b) adsorption isotherms of dissolved lead [Pb(Ⅱ)] ion on the metal oxide particles containing aluminum and titanium were determined as follows, respectively,(a) , (b) at pH 6where, correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.95 and 0.96, respectively.The overall adsorption rate of Pb(Ⅱ) on the metal oxide particles containing aluminum and titanium was determined by a differential bed reactor. The overall adsorption rate at pH 6 was as a following equation.at pH 6

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1213-1223
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• 2000

The adsorption characteristics of phenol has been studied by using CDQ (Cokes Drying Quenching) dust as an adsorbent. The adsorption capacity of CDQ dust was shown to be 42% about removal for 300 ppm phenol solution at the equilibrium adsorption time of 60 min. Removal percentage of phenol increased as the initial phenol concentration was raised in the experimental conditions and the adsorption behavior was explained well by Freundlich adsorption isotherm. Kinetic study showed that the adsorption followed 1st, 1.5th, and 2nd-order rate equation in the sequence as the adsorption time passed. Since the adsorption amount of phenol was increased as the adsorption temperature was raised, the adsorption was thought to be endothermic, and several thermodynamic parameters have been calculated based upon experimental data. Adsorbed amount of phenol on CDQ dust changed little according to the variation in the solution pH except for the slight decrease under the strong alkaline condition.

• 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.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.95-103
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• 2004

This study has been assessed the influence of applying sewage sludge to soil amendments on the sorption properties, and leaching potential of three commonly used organophosphorus pesticides, Diazinon, Fenitrothion, and Chlorpyrifos. A sandy soil with a low content of organic carbon was treated with sewage sludge with a ratio sandy soil sludge ratio of 30:1. The sorption was determined with the batch equilibrium technique. The sorption isotherms could be described by Freundlich equation. The Freundlich constant, K value which measures sorption capacity, were 3.97, 9.94, 22.48 for Diazinon, Fenitrothion, Chlorpyrifos in non-amended soil. But in amended soil, K value was 12.58, 28.47, and 61.21 for Diazinon, Fenitrothion, and Chlorpyrifos. The overall effect of sewage sludge addition to soil was to increase pesticides adsorption, due to the high sorption capacity of the organic matter. The effect of sludge on the leaching of pesticides in the soil was studied using packed soil columns. Total recoveries of pesticides in soil and leachate with leaching in soil column, were in the range of about 73∼84%, was reduced with the passage of time. Diazinon moved more rapidly than Chlorpyrifos in the unamended soil due to greater sorption and lower water solubility of Chlorpyrifos. Total amounts of pesticides leached from the sewage sludge amended soils were significantly reduced when compared with unamended soils. This reduction may be mainly due to and increase in sorption in amended soils, as a consequence of the increase in the organic matter content.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.75-80
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• 1998

Ammonium ion is notorious for the adverse effects upon many of the important uses of water such as toxcity to fish, corrosion of metals and concrete, and concern over man's consumption. A clinoptilolite, which is a naturally occurring zeolite selective for ammonium ion exchange, has been used. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir equation or by the Freundlich equation. As the particle size of the clinoptilolite decreased, exchange capacity was increased. The smaller particle size enhaced the exchange of ammonium ion due to the greater surface area and decreased diffusion to the exchange sites within the zeolite. Ammonium ion exchange capacity tended to decrease when the temperature increased from $20^{\circ}C$ to $35^{\circ}C$, and the temperature correction factor was found to be 0.98 in the Langmuir equation.