• Macromolecular Research
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• v.16 no.6
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• pp.492-502
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• 2008

This study examined the adsorption of a synthetic cutting fluid and cutting fluid effluent on chitosan and SDS-modified chitosan, Chitosan and SDS-modified chitosan were prepared in form of beads and fibers. A series of batch experiments were carried out as a function of the initial concentration of cutting fluid, contact time and pH of the fluid. The contact angle study suggested that the SDS-modified chitosan was more hydrophobic than chitosan. The Zeta potential study showed that chitosan, SDS-modified chitosan and synthetic cutting fluid had a point of zero charge (PZC) at pH 7.8, 9 and 3.2, respectively. SDS-modified chitosan has a greater adsorption capacity than chitosan. The experimental results show that adsorption capacity of the cutting fluid on 1.0 g of SDS-modified chitosan at pH 3 and for a contact time of 120 min was approximately 2,500 g/kg. The adsorption capacity of chitosan and SDS-modified chitosan increased with decreasing pH. The Langmuir, Freundlich, and Brunauer Emmett and Teller (BET) adsorption models were used to explain the adsorption isotherm. The Langmuir isotherm fitted well with the experimental data of chitosan while the BET isotherm fitted well with the SDS-modified chitosan data. Pseudo first- and second-order kinetic models and intraparticle diffusion model were used to examine the kinetic data. The experimental data was fitted well to a pseudo second-order kinetic model. The significant uptake of cutting fluid on chitosan and SDS-modified chitosan were demonstrated by FT-IR spectroscopy, SEM and heat of combustion.

• Carbon letters
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• v.7 no.3
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• pp.171-179
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• 2006

A carbonaceous sorbent was prepared from rice husk via sulphuric acid treatment. After preparation and washing, the wet carbon with moisture content 85% was used in its wet status in this study due to its higher reactivity towards Cr(VI) than the dry carbon. The interaction of Cr(VI) and the carbon was studied and two processes were investigated in terms of kinetics and equilibrium namely Cr(VI) removal and chromium sorption. Cr(VI) removal and chromium sorption were studied at various initial pH (1.6-7), for initial Cr(VI) concentration (100 mg/l). At equilibrium, maximum Cr(VI) removal occurred at low initial pH (1.6-2) where, Cr(III) was the only available chromium species in solution. Cr(VI) removal, at such low pH, was related to the reduction to Cr(III). Maximum chromium sorption (60.5 mg/g) occurred at initial pH 2.8 and a rise in the final pH was recorded for all initial pH studied. For the kinetic experiments, approximate equilibrium was reached in 60-100 hr. Cr(VI) removal data, at initial pH 1.6-2.4, fit well pseudo first order model but did not fit pseudo second order model. At initial pH 2.6-7, Cr(VI) removal data did not fit, anymore, pseudo first order model, but fit well pseudo second order model instead. The change in the order of Cr(VI) removal process takes place in the pH range 2.4-2.6 under the experimental conditions. Other two models were tested for the kinetics of chromium sorption with the data fitting well pseudo second order model in the whole range of pH. An increase in cation exchange capacity, sorbent acidity and base neutralization capacity was recorded for the carbon sorbent after the interaction with acidified Cr(VI) indicating the oxidation processes on the carbon surface accompanying Cr(VI) reduction.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.37-44
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• 2012

This study investigated on the adsorption of nonpoint pollution source using the Sand, hydroxyapatite(HAP), Zeolite and mixed culture. The adsorption of nonpoint pollution source on Sand, hydroxyapatite(HAP), Zeolite and mixed culture was investigated during a series of batch adsorption experiments. After the batch absorption experiments analysed COD, T-N, T-P on adsorption water. The experimental data was analysed using the pseudo-first-order adsorption kinetic models. Langmuir and Freundlich isotherm models were tested for their applicability. The maximum adsorbed amount $(Q_{max})$ of COD were found to be sand 0.0511mg/g, HAP 0.1905mg/g, Zeolite 1.0366mg/g and Mixed media 0.7444mg/g. The maximum adsorbed amount $(Q_{max})$ of T-N were found to be sand 0.0159mg/g, HAP 0.0537mg/g, Zeolite 0.5496mg/g and Mixed media 0.1374mg/g. The maximum adsorbed amount $(Q_{max})$ of T-P were found to be sand 0.0202mg/g, HAP 0.1342mg/g, Zeolite 0.0462mg/g and Mixed media 0.1180mg/g. As a result, the mixed media was effective to remove nonpoint pollution source.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.505-512
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• 2017

The adsorption characteristics of Sr ion in aqueous solution was examined using zeolite NaA powder (Z-PA) and pellets (Z-BA). In batch experiment, the adsorption of Sr ions by Z-BA and Z-PA was well expressed by pseudo-second-order kinetic model than psedo-first-order kinetic model. Experimental isotherm results was well fitted to Langmuir isotherm model and the maximum adsorption capacities obtained from Langmuir isotherm model were 233.32 mg/g for Z-PA and 164.60 mg/g for Z-BA, respectively. The continuous experiment results showed that the total Sr ion uptake (q) increased, but the breakthrough time, effluent volume ($V_{eff}$) and total removal (R) of Sr ion decreased with the Sr ion concentration. The breakthrough curves obtained from the experiment was modeled by Thomas model.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.77-84
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• 2022

The experimental work has been carried out for the study of pyrolysis of oil samples used in industrial and utility boilers in Korea. For five oil samples, the characteristics of pyrolysis have been investigated with a thermogravimetric analyzer (TGA), and their kinetic parameters were obtained and compared each other. The rate order of pyrolysis rate for five oils were as follows: by-product fuel oil, pyrolysis oil, diesel, a heavy oil and refined oil. The pyrolysis of refined oil has been successfully described by the three step, first order reaction model while the single step reaction model has been used for other oils. For the reaction temperature over 550 K, the reactivity of refined oil was very poor compared with other oils.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.210-216
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• 2015

Adsorption of brilliant blue FCF dye using coal based the granular activated carbon from aqueous solution was investigated. Batch experiments were carried out as a function of the adsorbent dose, initial concentration, contact time and temperature. The equilibrium adsorption data were fitted to Langmuir, Freundlich and Temkin models. The results indicate that Freundlich model provides the best correlation of the experimental data. Base on the estimated Freundlich constant (1/n = 0.129~0.212), this process could be employed as an effective treatment method. Adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. It was shown that the pseudo-second-order kinetic equation could describe well the adsorption kinetics. The negative Gibbs free energy value (-4.81~-10.33 kJ/mol) and positive enthalpy value (+78.59 kJ/mol) indicated that the adsorption was a spontaneous and endothermic process.

• Environmental Engineering Research
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• v.15 no.4
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• pp.207-213
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• 2010

This study investigated the potential of using bottom ash to be used as an adsorbent for the removal of lead (Pb) from aqueous solutions. The physical and chemical characteristics of bottom ash were determined, with a series of leaching and adsorption experiments performed to evaluate the suitability of bottom ash as an adsorbent material. Trace elements were present, such as silicon and aluminum, indicating that the material had a good adsorption capacity. All heavy metals leached during the Korea standard leaching test (KSLT) passed the regulatory limits for safe disposal, while batch adsorption experiments showed that bottom ash was capable of adsorbing Pb (experimental $q_e$ = 0.05 mg/g), wherein the adsorption rate increased with decreasing particle size. The adsorption data were then fitted to kinetic models, including Lagergren first-order and Pseudo-second order, as well as the Elovich equation, and isotherm models, including the Langmuir, Freundlich and Dubinin-Radushkevich isotherms. The results showed that pseudo-second order kinetics was the most suitable model for describing the kinetic adsorption, while the Freundlich isotherm best represented the equilibrium sorption onto bottom ash. The maximum sorption capacity and energy of adsorption of bottom ash were 0.315 mg/g and 7.01 KJ/mol, respectively.

• Environmental Engineering Research
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• v.25 no.4
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• pp.605-613
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• 2020

This study is to investigate the possibility of using activated carbon prepared from Iraqi date-pits (ADP) which are produced from palm trees (Phoenix dactylifera L.) as low-cost reactive material in the permeable reactive barrier (PRB) for treating lead (Pb⁺²) from the contaminated groundwater, and then compare the results experimentally with other common reactive materials such as commercial activated carbon (CAC), zeolite pellets (ZP). Factors influencing sorption such as contact time, initial pH of the solution, sorbent dosage, agitation speed, and initial lead concentration has been studied. Two isotherm models were used for the description of sorption data (Langmuir and Freundlich). The maximum lead sorption capacities were measured for ADP, CAC, and ZP and were found to be 24.5, 12.125, and 4.45 mg/g, respectively. The kinetic data were analyzed using various kinetic models particularly pseudo-first-order, pseudo-second-order, and intraparticle diffusion. COMSOL Multiphysics 3.5a depend on finite element procedure was applied to formulate transmit of lead (Pb⁺²) in the two-dimensional numerical (2D) model under an equilibrium condition. The numerical solution shows that the contaminant plume is hindered by PRB.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.691-698
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• 2016

This study was carried out to investigate the characterization of iron oxide nanotubes (INTs) by anodization method and applied adsorption isotherms and kinetic models for phosphate adsorption. SEM analysis was conducted to examine the INTs surface formation. Further XRD and XPS analysis were performed to observe the crystal structure of INTs before and after phosphate adsorption. AFM analysis was conducted to determine of Fe foil surface before and after anodization. Phosphate stock solution for adsorption experiment was prepared by $KH_2PO_4$. The batch experiment was conducted using 20 ml phosphate stock solution and $40cm^3$ of INTs in 50 ml conical tube. Adsorption isotherms were applied Langmuir and Freundlich models for adsorption equilibrium test of INTs. Pseudo first order and pseudo second order models were applied for interpretation of adsorption rate by reaction time. The determination coefficient ($R^2$) values of Langmuir and Freundlich models were 0.9157 and 0.8876 respectively.

• Journal of Environmental Science International
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• v.20 no.2
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• pp.241-249
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• 2011

In this research, equilibrium of adsorption and kinetics of As(V) removal were investigated. The coal mine drainage sludge(CMDS) was used as adsorbent. To find out the physical and chemical properties of CMDS, XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometer) analysis were carried out. The CMDS was consist of 70% of goethite and 30% of calcite. From the results, an adsorption mechanism of As(V) with CMDS was dominated by iron oxides. Langmuir adsorption isotherm model was fitted well more than Freundlich isotherm adsorption model. Adsorption capacities of CMDS 1 was not different with CMDS 2 on aspect of amounts of arsenic adsorbed. The maximum adsorption amount of two CMDS were respectively 40.816, 39.682 mg/g. However, the kinetic of two CMDS was different. The kinetic was followed pseudo second order model than pseudo first order model. Concentrations of arsenic in all segments of the polymer in CMDS 2 does not have a constant value, but the rate was greater than the value of CMDS 1. Therefore, CMDS 2, which is containing polymer, is more effective for adsorbent to remove As(V).