• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.131-138
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• 2005

Freundlich isotherms and Toth isotherms were obtained for benzene adsorption on activated carbon and zeolite 13X in static experiments. Breakthrough curves of benzene were measured in adsorption bed packed with the same adsorbents. Relation between breakthrough times and partial pressure of benzene was analyzed and the Freundlich isotherm parameters were determined. Adsorption amount of benzene predicted by the analysis of breakthrough experimental results was relatively consistent with that predicted by the static experimental results. Dynamic experiments for activated carbon bed, where more symmetric breakthrough curves were obtained, produced smaller errors with zeolite bed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.936-943
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• 1997

Biosorbents of nonliving, dried marine brown algae Undaria pinnatifida, Hizikia fusiformis, and Sargassum fulvellum were investigated for their lead biosorption performances. As the amount of biosorbent added was increased, the lead removal by biosorbent materials increased but the lead biosorption capacities decreased. However the lead biosorption capacity by the biosorbent materials increased with increasing initial lead concentration and pH in the range of $C_o\;10\~500\;mg/L$. Among the biosorbent materials used in this study, the lead biosorption capacity in the solutions with no pH adjustment decreased in the following sequence: U. pinnatifida > H. fusiformis > S. fulvellum. Equilibrium parameters based on Langmuir and Freundlich isotherm were determined. It was found that the lead biosorption by biosorbent materials were expressed by the Langmuir isotherm better than the Freundlich isotherm.

• Resources Recycling
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• v.8 no.1
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• pp.37-43
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• 1999

Studies have been conducted for the purpose of using manganese nodule and residue remained after extracting valuable metals [mm it as the adsorbent of cadmium wastewater. The study observed the adsorption percentage according to initial cadmium concentration and interpreted each adsorption systems by applying the Freundlich, Langmuir, and Temkin isotherms. The adsorption amounts increased as the initial concentration at cadmium ion increased, whereas the adsorption percentage decreased. Linearity was shown when applied to the Freundlich and Langmuir isotherms. The k value which evaluates the adsorption capacity of adsorbent in Freundlich isotherm, turned out to be 11.72, the highest in case of manganese nodule. The Xm value, the maximum adsorption amount of the adsorbate that adsorbs as a monolayer in Langmuir isotherm of manganese nodule, was estimated as 0.16, representing higher value compared with those of leached residue, leached residue-raw manganese nodule mixture, and activated carbon.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.245-250
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• 2008

Adsorption experiment was carried out to find the adsorption capacity and characteristics of heavy metals(Cd, Pb) onto soil and mixed soil with food compost. Result showed that mixed soil having higher organic content adsorbed more heavy metal than soil, indicating that food compost can be used effectively to prevent soil pollution. Linear adsorption isotherm which adopted to find the adsorption characteristics was used to calculate Retardation Factor(R). The value of Retardation Factor(R)s of Pb and Cd in mixed soil, found as 34.54, 24.42 respectively, are higher than those in soil which were found as 4.64, 3.67, respectively. The value of Retardation Factor(R) using Freundlich adsorption isotherm could be presented by the functions of concentration and showed similar result as the linear one. But Freundlich adsorption isotherm showed higher relationship than linear one and the retardation factor(R) from freundlich adsorption isotherm was thought as more effective method to assess adsorption capacity because it could reflect gradient and intercept of the isotherm.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.201-210
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• 2020

2 (Langmuir, Freundlich, Elovich, Temkin, and Dubinin-Radushkevich) and 3 (Sips and Redlich-Peterson)-parameter isotherm models were applied to evaluated for the applicability of adsorption of Cu(II) and/or phosphate isotherm using chitosan bead. Non-linear and linear isotherm adsorption were also compared on each parameter with coefficient of determination (R²). Among 2-parameter isotherms, non-linear Langmuir and Freundlich isotherm showed relatively higher R² and appropriate maximum uptake (q_m) than other isotherm equation although linear Dubinin-Radushkevich obtained highest R². 3-parameter isotherm model demonstrated more reasonable and accuracy results than 2-parmeter isotherm in both non-linear and linear due to the addition of one parameter. The linearization for all of isotherm equation did not increase the applicability of adsorption models when error experiment data was included.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.460-467
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• 2006

Adsorption experiments for $H_2$, $CO_2$, CO, and their binary mixtures on zeolite 5A were performed by static volumetric method. Experimental data were obtained at temperatures of 293.15, 303.15 and 313.15 K and at pressures to 25 atm. The parameters obtained from single component adsorption isotherm. Multicomponent adsorption equilibria could be predicted and compared with experimental data. Langmuir isotherm, Langmuir-Freundlich isotherm and Dual-Site Langmuir isotherm be used to predict the experimental results for binary adsorption equilibria of $CO_2/CO$ and $H_2/CO_2$ on zeolite 5A. Dual-Site Langmuir isotherm showed the best agreement with the experimental results.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.1
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• pp.9-19
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• 1998

A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash(RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portalnd Rice Husk Ash Cement (PRHAC) which contained rice husk ash 50 percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

• Environmental Engineering Research
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• v.22 no.1
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• pp.95-107
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• 2017

Adsorption equilibrium and kinetic behavior of two toxic heavy metals hexavalent chromium [Cr(VI)] and mercury [Hg(II)] on mustard oil cake (MOC) was studied. Isotherm of total chromium was of concave type (S1 type) suggesting cooperative adsorption. Total chromium adsorption followed BET isotherm model. Isotherm of Hg(II) was of L3 type with monolayer followed by multilayer formation due to blockage of pores of MOC at lower concentration of Hg(II). Combined BET-Langmuir and BET-Freundlich models were appropriate to predict Hg(II) adsorption data on MOC. Boyd's model confirmed that external mass transfer was rate limiting step for both total chromium and Hg(II) adsorptions with average diffusivity of $1.09{\times}10^{-16}$ and $0.97m^2/sec$, respectively. Desorption was more than 60% with Hg(II), but poor with chromium. The optimum pH for adsorptions of total chromium and Hg(II) were 2-3 and 5, respectively. At strong acidic pH, Cr(VI) was adsorbed by ion exchange mechanism and after adsorption reduced to Cr(III) and remained on MOC surface. Hg(II) removal was achieved by complexation of $HgCl_2$ with deprotonated amine ($-NH_2$) and carboxyl (COO-) groups of MOC.

• Carbon letters
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• v.10 no.1
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• pp.23-32
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• 2009

The adsorption of phenolic compound resorcinol on activated carbons prepared from Moringa oleifera (Drumstick bark) has been investigated. Activated carbon was prepared by impregnating Moringa oleifera with 50% phosphoric acid in the ratio of 1:1 and 1:2(w/w), designated as MOAC1 and MOAC2. Equilibrium and isotherm studies were carried out. The influences of variables such as contact time, initial concentration of resorcinol, carbon dosage in the solution on percentage adsorption and adsorption capacity of the bark have been analysed. The equilibration time was found to be 4 h. Kinetics of resorcinol onto activated carbons was checked for pseudo first order and pseudo second order model. It was found that the adsorption of resorcinol follows pseudo second order kinetics for both MOAC1 and MOAC2. The isotherm data were correlated with isotherm models, namely Langmuir and Freundlich. Adsorption isotherms were satisfactorily fitted by both the Langmuir and Freundlich model for MOAC1 and MOAC2.

• 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.