• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.663-669
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• 2009

The honeycomb adsorbent was prepared for adsorbing and seadsorbent was prepared by using zeolite sheet, which contained zeolite as component. The steady-state adsorption properties and surface morphologies were analyzed and breakthrough characteristics were ananlyzed by providing 16% carbon dioxide mixed gas. By thermal regeneration, carbon dioxide concentration properties were analyzed, and the adsorptive separation process was compared between thermal swing adsorption and pressure swing adsorption after adsorbent temperature change during heating. The breakthrough results of the honeycomb showed possibility parating carbon dioxide from combustion exhaust gas, which had deep impact on climate change, and the characteristics of the adsorbent were studied. Na-X zeolite was coated on a honeycomb prepared with ceramic sheet or active carbon sheet so that the two honycomb can be used at high temperature. Third honeycomb of rotary adsorptive concentration process.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.183-189
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• 2010

It is of importance to separate Ni(II) and Co(II) from Mg(II) in solution which was leached from nickel laterite ore. In order to investigate the possibility of separating Ni(II) and Co(II) from Mg(II), adsorption behavior of the three metals from individual and mixed sulfate solutions was investigated by using Diphonix resin. The concentration of each metal in solution was fixed at 100 ppm and the pH of the sulfuric acid solution was changed from 5 to 7. At ambient temperature, the adsorption behavior of the three metal ions followed Langmuir adsorption isotherm. The loading capacity of Diphonix resin for the three metal ions was obtained from the Langmuir isotherm. Since adsorption behavior of the three metal ions from the mixed solution was similar to each other, it was found to be difficult to separate Ni(II) and Co(II) from Mg(II) by using Diphonix resin.

• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.1-6
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• 1986

The hydration of $C_3A$ and $C_3A-CaSO_4$.$2H_2O$ was investigated with varying concentration (0.1-1.0%) of sodium gluconate solution. gluconate solution. Sodium gluconate accelerates cation dissolution from $C_3A$ for the first several minutes but depresses the rate of heat evolution in the course of $C_3A$ hydration. The hydration of $C_3A$ in the presence of sodium gluconate was modified such that the formation of the intermediate hydrate C4AH$\chi$ crystal was much reduced and most of the product became amorphous. The retardation of $C_3A-CaSO_4$.$2H_2O$ hydration in the presence of sodium gluconate was controlled by the competitive adsorption between gluconate anion and $SO_4^{-2}$ onto $C_3A$ surface.

• Ecology and Resilient Infrastructure
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• v.5 no.1
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• pp.19-24
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• 2018

Water quality is affected by the pollutants flowing into rivers since the interaction between water bodies and sediments in various environmental conditions. Especially, accumulation of sediments increases in the stagnant water areas due to a relative long hydrological retention time in the water bodies. Therefore, it is an important factor of water quality to understand characterization of the material behavior in water bodies and sediments. In this study, the objective of the conditional experiments was small and medium sized streams located in Gyeonggi-do. To estimate how the changes of fluoride behavior, depending on the pH, ion type, concentration, and clay contents. The pH results showed a trend that adsorption amount of fluorine decreased and the dissolution of fluorine increased following by pH increasing. The concentration and type of ions results showed that $Cl^-$ and $SO{_4}^{2-}$ ions had no significant effect on the adsorption ability of fluorine, the amount of dissolution was increased because $OH^-$ ion had active competition with fluorine in the reaction. The ingredient of sediment results showed that the amounts of fluoride adsorption and dissolution were reduced in samples, which contain relatively large amounts of Silt and Clay components. This means that the environmental conditions of water bodies greatly affect the adsorption and dissolution of fluoride in the sediments, so that proper management of fluoride in the sediments must precede an understanding of the environmental conditions of the water bodies.

• Corrosion Science and Technology
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• v.12 no.2
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• pp.65-78
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• 2013

The present investigation deals with the corrosion inhibition of mild steel in 1M $H_2SO_4$ with 1, 4-dihydro pyridine and its derivatives prepared using microwave activation method. The synthesis of inhibitor was confirmed by IR spectra. The effect of 1, 4-dihydropyridine derivatives on the corrosion inhibition of mild steel in 1M $H_2SO_4$ was studied using weight loss and electrochemical polarization techniques. Influence of temperature (303-333K) and synergistic effect of halide ions ($I^-$, $Br^-$ and $Cl^-$) on the inhibition behaviour was also studied. Corrosion products on the metal surface were analyzed by scanning electron microscopy (SEM) and a possible mechanism of inhibition by the compounds is suggested. Thermodynamic parameters were calculated using weight loss data in order to elaborate the mechanism of corrosion inhibition. Polarization measurements revealed that the studied compounds acted as mixed type inhibitor but slightly anodic in nature. Electrochemical impedance measurements revealed that the compounds were adsorbed onto the carbon steel surface and the adsorption obeyed the Langmuir adsorption isotherm. The synergistic effect of halide ions on the IE increases with increase in concentration. The IE obtained from atomic absorption spectrophotometric studies was found to be in good agreement with that obtained from the conventional weight loss method. SEM revealed the information of a smooth, dense protective layer in presence of the inhibitors.

• Resources Recycling
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• v.15 no.3 s.71
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• pp.58-65
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• 2006

The applicability of the waste pulp which produced in the paper recycling process as an adsorbent for the treatment of $Ni^{2+}$ ion in wastewater has been investigated taking the initial concentration of adsorbate, temperature, the amount of adsorbent, and solution pH as the experimental variables. In addition, the effect of the concentration of coexisting solute and pre-treatment of adsorbent on the adsorbability of $Ni^{2+}$ ion were also examined. The electrokinetic potential of waste pulp was observed to be positive below pH 7.8 and negative above this pH. The adsorption reaction of $Ni^{2+}$ ion reached its equilibrium within 4 hours after the reaction was initiated and the adsorbed amount of adsorbate was found to increase with its initial concentration. The adsorbability of $Ni^{2+}$ was raised with temperature so that its adsorption reaction was considered to be exothermic, which was substantiated by thermodynamic calculation. Also, the adsorbed amount of $Ni^{2+}$ was raised with the amount of waste pulp and with pH in the range of pH $3{\sim}6$. This behavior of the adsorption of $Ni^{2+}$ according to the solution pH was well agreed with the electrokinetic characteristics of waste pulp in solution. The amount of coexisting solute was observed to reversely affect on the $Ni^{2+}$ adsorption onto waste pulp under the experimental conditions. With regard to the pre-treatment of adsorbent with NaOH, the adsorbability of $Ni^{2+}$ was increased with the concentration of NaOH to a certain extent. However, it was found to decrease contrarily when the concentration of NaOH became too high.

• Journal of Conservation Science
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• v.30 no.2
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• pp.235-241
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• 2014

In this study, we are trying to verify humidity control capability of the exhibition environment of cultural property by measuring adsorption and desorption performance, the control ability of harmful substances by the adsorption experiments of harmful gases. In the experiment of adsorption and desorption performance, in the low humidity area, Artsorb desorbed overwhelmingly more than activated carbon whereas activated carbon absorbed more. Adsorption speed was faster slightly in Artsorb absorption speed was similar in both. In the middle humidity area, absorption by artsorb was slightly more and desorption was similar in both so characteristic of Artsorb didn't appear. Also, Adsorption speed was faster in activated carbon but in the process of desorption, the speed of Artsorb was faster. In adsorption experiment of harmful substances, the concentration in the environment with activated carbon was lower than one with Artsorb, but the difference appeared small. And as a result of observation of the difference in concentration due to adsorption of harmful gas by the change in the metal specimen, the most change was shown in lead specimen and the color difference between the lead specimens of the activated carbon and Artsorb appeared greatly.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.93-100
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• 2008

For investigation of adsoption properties of cadmium elimination by wood charcoal, $25m{\ell}$ aqueous cadmium solutions in various concentrations were treated with 0.2 g wood charcoal of Red Oak (Quercus mongolica) for 280 minutes. Almost 100% of cadmium elimination ratio was obtained in the solutions with initial concentration of 20 and 40 ppm in the treatment, whereas they were 75 and 50% in those of 80 and 160 ppm. In the effect of treatment time, the highest amount of cadmium ions was eliminated during the first ten minutes in each solution so that the elimination ratio of each case was over 70% of the maximum elimination value. From the analysis of adsorptive cadmium adsorption mechanism using the Langmuir adsorption isotherm, it was suggested that cadmium ion molecules were adsorbed at the active sites on the charcoal particle in form of one layer. The Gibbs free energy of the adsorption process was calculated in negative value for each solution. This means the adsorption processes are spontaneous which do not require the extra input energy.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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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.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.207-215
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• 2020

Vivianite (Fe₃²⁺(PO₄)2·8H₂O) and green rust ([Fe₄²⁺Fe₂³⁺(OH)^-₁₂][SO₄^2-·2H₂O]^2-), ferrous containing minerals, could remove aqueous U(VI) in 5 min. and the efficiencies of green rust were roughly 2 times higher than that of vivianite. The zeta potential measurement results implies that the better performance of green rust might be attributed to the favorable surface charge toward uranyl phosphate species. The removal behaviors of the minerals were well fitted by pseudo-second order kinetic model (R² > 0.990) indicating the dominant removal process was chemical adsorption. Effects of Ca²⁺ and CO₃^2- at pH 7 were examined in terms of removal kinetic and capacity. The kinetic constants of aqueous U(VI) were 8 and 13 times lower (0.492 × 10^-3 g/(mg·min); 0.305 × 10^-3 g/(mg·min)) compared to the value in the absence of the ions. The thermodynamic equilibrium calculation showed that the stable uranyl species (uranyl tri-carbonate) were newly formed at the condition. Surface investigation on the reacted mineral with uranyl phosphates species were carried out by XPS. Ferrous iron and U(VI) on the green rust surface were completely oxidized and reduced into Fe(III) and U(IV) after 7 d. It suggests that the ferrous minerals can retard U(VI) migration in phosphate-rich groundwater through the adsorption and subsequent reduction processes.