• 한국환경과학회지
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• 제22권11호
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• pp.1433-1441
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• 2013

The adsorption ability of wood-based activated carbon to adsorb methylene blue (MB) and crystal violet (CV) from aqueous solution has been investigated. Adsorption studies were carried out on the batch experiment at different initial MB and CV concentrations (MB=150 mg/L~400 mg/L, CV=50 mg/L~350 mg/L), contact time, and temperature. The results showed that the MB and CV adsorption process followed the pseudo-second-order kinetic and intraparticle diffusion was the rate-limiting step. Adsorption equilibrium data of the adsorption process fitted very well to both Langmuir and Freundlich model. The maximum adsorption capacity ($q_m$) by Langmuir constant was 416.7 mg/g for MB and 462.4 mg/g for CV. The thermodynamic parameters such as ${\Delta}H^{\circ}$, ${\Delta}S^{\circ}$ and ${\Delta}G^{\circ}$ were evaluated. The MB and CV adsorption process was found to be endothermic for the two dyes.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.406-414
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• 2010

A novel polyacrylamide grafted hydrous ferric oxide adsorbent composite has been synthesized by using glow discharge electrolysis plasma. To optimize the synthesis conditions, the following parameters were examined in detail: applied power, discharge time, post polymerization temperature, post polymerization time, amount of crosslinking agent and hydrous ferric oxide gel added and so on. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The removal percentage of the adsorbent in Pb(II) solution was examined and the data obtained showed that the adsorbent composite has a high capacity for lead ion. For the use in wastewater treatment, the thermodynamic and kinetic of Pb(II)-capture were also studied. Results indicated that the adsorption reaction was a spontaneous and an endothermic process, and it seems to be obeyed a pseudo-secondorder rate model. Moreover, the adsorption isotherm of Pb(II)-capture is following the Langmuir and Freundlich isotherm models.

• Carbon letters
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• 제14권1호
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• pp.27-33
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• 2013

An increase in population initiating rapid industrialization was found to consequently increase the effluents and domestic wastewater into the aquatic ecosystem. In this research the potentialities of Sambucus nigra L. (SNL) plant in the remediation of water, contaminated with methylene blue (MB), a basic dye were investigated. SNL was chemically impregnated with $KHCO_3$. Operating variables studied were pH, amount of adsorbent and contact time. In general, pH did not have any significant effect on colour removal and the highest adsorption capacity was obtained in 0.035 g MB/g-activated carbon. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption models were applied to describe the equilibrium isotherms. The adsorption isotherm data were fitted to the Temkin isotherm. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order and chemisorption pseudo-second-order kinetic models. The sorption process obeyed the pseudo-second-order kinetic model. The surface area, pores volume and diameter were assessed by the Brunauer-Emmett-Teller and Barrett-Joyner-Halenda methods. The results were compared to those from activated carbon (Merck) and an actual sample. The results indicate that SNL can be employed as a natural and eco-friendly adsorbent material for the removal of dye MB from aqueous solutions.

• 한국환경과학회지
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• 제8권3호
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• pp.387-391
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• 1999

$Pb^{2+}$ and $Cr^{3+}$ uptake capacity by Sargassum horneri was 185.5 mg $Pb^{2+}$/g biomass and 102.6 mg $Cr^{3+}$/g biomass, respectively. An adsorption equilibria were reached within about 0.5 hr for $Pb^{2+}$ and 1 hr for $Cr^{3+}$. The adsorption parameters for $Pb^{2+}$ and $Cr^{3+}$ were determined according to Langmuir and Freundlich model. With an increase in pH values of 2 to 5, $Pb^{2+}$ uptake was increased, however $Cr^{3+}$ uptake jwas constant. The selectivity of mixture solution showed the uptake order of $Pb^{2+}$>$Cu^{2+}$>$Cr^{3+}$>$Cd^{2+}$. $Pb^{2+}$ and $Cr^{3+}$ adsorbed by S. horneri could be recovered from 0.1M HCl, 0.1M ${HNO}_3$ and 0.1M EDTA by desorption process, and the efficiency of $Pb^{2+}$ desorption was above 98%, whereas the efficiency of $Cr^{3+}$ desorption was below 34%.

• Environmental Engineering Research
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• 제17권3호
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• pp.125-132
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• 2012

The removal of Cd(II) and Cu(II) from aqueous solution by an agricultural solid waste biomass prepared from Moringa oleifera bark (MOB) was investigated. The biosorbent was characterized by Fourier transform infrared spectroscopy and elemental analysis. Furthermore, the effect of initial pH, contact time, biosorbent dosage, initial metal ion concentration and temperature on the biosorption of Cd(II) and Cu(II) were studied using the batch sorption technique. Kinetic studies indicated that the biosorption process of the metal ions followed the pseudo-second order model. The biosorption data was analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. Based on the Langmuir isotherm, the maximum biosorption capacities for Cd(II) and Cu(II) onto MOB were 39.41 and 36.59 mg/g at 323 K, respectively. The thermodynamic parameters, Gibbs free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$), and entropy (${\Delta}S^o$) changes, were also calculated, and the values indicated that the biosorption process was endothermic, spontaneous and feasible in the temperature range of 303-323 K. It was concluded that MOB powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Cd(II) and Cu(II) ions from aqueous solution.

• Advances in environmental research
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• 제7권1호
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• pp.53-71
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• 2018

Waste glass disposal causes environmental problems in the cities. To find a suitable green environmental solution for this problem low cost adsorbent in this study was prepared from waste glass. An effective new green adsorbent was synthesized by hydrothermal treatment of waste glass (WG), followed by acidic activation of its surface by HCl (WGP). The prepared adsorbent was characterized by scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), and BET surface measurement. The developed adsorbent was used for the removal of heavy metals (Cd, Cu, Fe, Pb and Zn) from well water. Batch experiments were conducted to test the ability of the prepared adsorbent for the removal of Cd, Cu, Fe, Pb and Zn from well water. The experiments of the heavy metals adsorption by adsorbent (WGP) were performed at different metal ion concentrations, solution pH, adsorbent dosage and contact time. The Langmuir and Freundlich adsorption isotherms and kinetic models were used to verify the adsorption performance. The results indicated high removal efficiencies (99-100%) for all the studied heavy metals at pH 7 at constant contact time of 2 h. The data obtained from adsorption isotherms of metal ions at different time fitted well to linear form of the Langmuir sorption equation, and pseudo-second-order kinetic model. Application of the resulted conditions on well water demonstrated that the modified waste glass adsorbent successfully adsorbed heavy metals (Cd, Cu, Fe, Pb and Zn) from well water.

• Membrane and Water Treatment
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• 제11권2호
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• pp.131-139
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• 2020

The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

• Advances in environmental research
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• 제4권2호
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• pp.69-81
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• 2015

A new magnetite-silica core/shell nanocomposite ($Fe_3O4@nSiO_2@mSiO_2$) was synthesized and functionalized with trimethylchlorosilane (TMCS). The prepared nanocomposite was used for the removal of diesel oil from aqueous media. The characterization of magnetite-silica nanocomposite was studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), surface area measurement, and vibrating sample magnetization (VSM). Results have shown that the desired structure was obtained and surface modification was successfully carried out. FTIR analysis has confirmed the presence of TMCS on the surface of magnetite silica nanocomposites. The low- angle XRD pattern of nanocomposites indicated the mesoscopic structure of silica shell. Furthermore, TEM results have shown the core/shell structure with porous silica shell. Adsorption kinetic studies indicated that the nanocomposite was able to remove 80% of the oil contaminant during 2 h and fit well with the pseudo-second order model. Equilibrium studies at room temperature showed that the experimental data fitted well with Freundlich isotherm. The magnetic property of nanocomposite facilitated the separation of solid phase from aqueous solution.

• Environmental Engineering Research
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• 제25권2호
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• pp.163-170
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• 2020

Knowledge of organic micropollutant transfers in barrier seal materials from waste storage facilities is limited to volatile organic compounds and phenolic compounds at ambient temperature. This study focused on the sorption of chlorophenols (CPs) from various geotextiles from clay geosynthetics under the influence of temperature. Also to study the impact of the polarity or the amount of CPs adsorbed on geotextiles with the partition coefficient. The effect of various parameters such as contact time, effect of temperature, initial CPs concentration and adsorbent dosage has been carried out in this study. The result obtained is non-linear and the data was calculated for affinity with Freundlich isotherm model. An important observation is that the amount of CPs sorbed on geotextiles increases with a growing number of chlorine atoms, ie increases with the partition coefficient (log K_ow). During this study, a decrease in adsorbent properties was observed with the rise in temperature from 23℃ to 55℃. The partitioning coefficients for CPs examined range are from 2.4 (R² = 0.86) to 8.4 mL/g (R² = 0.90). Among the CPs studied, the highest adsorbed quantity was observed for pentachlorophenol with 0.052 g/g at 23℃, this quantity will decrease with the increase in temperature.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.19-22
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• 2001

The effects of pH on the sequential sorption/desorption of chlorinated phenols (2-chlorophenol, 2.4-dichlorophenol and 2,4,5-trichlorophenol) in HDTMA-montmorillonite were investigated by maintaining pH 4.85 or 9.15 in the sequential batch sorption and desorption experiments. The chlorinated phenols are hydrophobic ionizable orginic compounds; they can exist as either neutral (pH << pKa) or anionic (pH >> pKa) forms. Among the tested chlorinated phenols, 2,4,5-trichlorophenol showed the highest sorption affinity at pH 4.85 as expected by the $K_{ow}$ . Neutral speciation at pH 4.85 exhibited higher sorption affinity than anionic speciation at pH 9.15. Our results indicates that desorption of chlorinated phenols is strongly dependent on pH of the aqueous phase. Freundlich model was used to analyze the single-solute sorption/desorption results. The ideal adsorbed solution theory(IAST) was employed to predict the hi-solute sorption/desorption equilibria.