• Membrane Journal
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• v.14 no.1
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• pp.75-84
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• 2004

In this study, we present a noble study far membrane transport models using chlorine resistance of polyamide RO membranes. Membrane transport mechanism is investigated by the comparison of membrane permeation performance under the continuous and Intermittent operation modes with mixed feed solution containing NaOCl and NaCl. Analysis of permeation performance indicates that solution-diffusion model and preferential adsorption-capillary flow model are relatively efficient according to operation mode. Under the continuous flow state, mass transfer depends on preferential adsorption-capillary flow model rather than solution-diffusion model. On the other hand, it prefers solution-diffusion model to preferential adsorption-capillary flow model under the stationary state. SEM images of NaOCl treated membrane surfaces strongly support these conclusions. These surface images reveal that NaOCl treated membrane in continuous operation mode exhibits ridge and valley structure in some fraction of the surface area, whereas that in intermittent operation mode shows surface degradation entirely.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.1
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• pp.67-74
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• 2001

In the manufacturing process of PCB , three kinds of VOCs such as aceton, methanol and 2-metoxyethanol are being used. In this study, adsorption characteristics of activated carbon fibers(ACFs) and active carbon were examined to temove these VOCs. The experimental results showed that ACF has better adsorption and regeneration efficiency than activated carbon. Phenolic-resin based ACF showed the highest adsorption capacity and the capacity was not decreased after repeated regeneration by steam. On the adsorption and desorption experiments for ternary components, preferential adsorption with roll-over phenomena was appeared. 2-Metoxyethanol was strong adsorbaste and it displaced adsorbed methanol and aceton.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.149-156
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• 2000

For the adsorption of polyelectrolyte at the surface of polyacrylamide gel particle, preferential adsorption of the large polyelectrolyte such as DNA is governed by the surface area of an adsorbent. The adsorption equilibrium constant can be varied by surface geometry of porous polymer, and it can be described as a function of ionic strength and surface area. Physical parameters affecting the adsorption were estimated using the theoretical governing equation of polyelectrolyte which electrophoretically moved along the column, and geometrical surface area was estimated by Waldman-Mayer's physical model. The separation of polyelectrolytes was studied using the physical parameters estimated by ionic strength and surface geometry.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.446-450
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• 2003

Maximum adsorption amount of the mixed culture, $2.06{\times}10^{11} cells/g$ is closed to the sum of that of each bacterial component: $1.39{\times}10^{11}cells/g$ for T. ferrooxidans and $1.08{\times}10^{11}cells/g$ for T. thiooxidans. These indicate that the two bacterial species have almost independent preferential adsorption sites on furnace dust. However, the efficiency of leaching, 35% for mixture, 45% for T.f. and 30% for T.t., was not linearly related to the ratio of adsorption in three different systems even though it was increased in parallel with the bacterial adsorption in the same system.

• Journal of the Korean Chemical Society
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• v.41 no.5
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• pp.239-245
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• 1997

The sorption kinetic was studied to evaluate feasibility of removing PCBs from mineral oil with activated carbon. Adsorption efficiency for Aroclor 1242 which is composed of lower chlorinated PCB formulations was $\geq$ 95%, whereas the adsorption efficiency for Aroclor 1260 having higher chlorinated constituents was considerably lower with the efficiency falling to 75%. The observed difference in the adsorption efficiency is attributed to the geometry of PCBs with non-planar and coplanar structure. The concentration of coplanar PCBs is appreciably higher in Aroclor 1242. Since toxicity is primarily associated with coplanar congeners, the preferential adsorption of coplanar congeners by activated carbon accounts for the fact that toxicity reduction can be achieved through this process. The efficiency of process was assessed in terms of Toxicity Equivalence Factor (TEF).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.81-81
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• 2010

Growth of TiO2 films prepared by atomic layer deposition (ALD) was studied on C fiber. Moreover, adsorption and photocatalytic decomposition of methylene blue on TiO2 thin films were studied. Preferential growth of TiO2 on steps of C surfaces could be identified by scanning electron microscopy (SEM). X-ray Photoelectron Spectroscopy (XPS) showed thickness-dependent positive core level shift of Ti, which can be interpreted in terms of enhanced final state charging for thicker films. Adsorption and photocatalytic behaviors of TiO2 thin films will be discussed in this poster.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.470-475
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• 2013

Zr-benzendicarboxylate structure, UiO-66 was prepared in 1-L batch scale by using a unique sonochemical-solvothermal combined synthesis method. The produced UiO-66 showed uniform particles of ca. $0.2{\mu}m$ in size with the BET surface area of $1,375m^2/g$ in high product yield (>95%). The UiO-66 showed 198 and 84 mg/g $CO_2$ adsorption capacity at 273 K and 298 K, respectively, with excellent $CO_2$ selectivity ($CO_2:N_2=32:1$) at ambient conditions. The isosteric heat of $CO_2$ adsorption varied from 33 to 25 kJ/mol as the adsorption progressed. The UiO-66 tested for xylene isomer separation in a liquid-phase batch mode confirmed preferential adsorption of the adsorbent for o-xylene over m-, and p-xylene.

• Textile Coloration and Finishing
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• v.19 no.3
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• pp.26-36
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• 2007

This study was carried out to treat the aqueous solutions containing reactive dyes(RB19, RR120 and RY179) by the Ozone demand flask method and adsorption process using activated carbon fiber(ACF) which are one of the main pollutants in dye wastewater. Ozone oxidation of three kinds of the reactive dyes was examined to investigate the reactivity of dyes with ozone, competition reaction and ozone utilization on various conditions for single- and multi-solute dye solution. Concentration of dyes was decreased continuously with increasing ozone dosage in the single-solute dye solutions. Competition quotient values were calculated to investigate the preferential oxidation of individual dyes in multi-solute dye solutions. Competition quotients(CQi) and values of the overall utilization efficiency, ${\eta}O_3$, were increased at 40mg/l of ozone dosage in multi-solute dye solutions. ACF(A-15) has much larger specific surface area$(1,584m^2/g-ACF)$ in comparison with granular activated carbon adsorbent (F400, $1,125m^2/g-GAC$), which is commonly used, and most of pores were found to be micropores with pore radius of 2nm and below. It was found that RB19 was most easily adsorbed among the dyes in this study. In the case of PCP (p-chlorophenol) and sucrose, which are single component adsorbate, adsorption capacities of ACF(A-15) were in good agreement with the batch adsorption measurement, and saturation time predicted of ACF columns for these components was also well agreed with practically measured time. But in the case of reactive dyes, which have relatively high molecular weight and aggregated with multi-components, adsorption capacities or saturation time predicted were not agreed with practically measured values.

• Journal of Hydrogen and New Energy
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• v.17 no.3
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• pp.241-247
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• 2006

The catalytic performances for CO preferential oxidation in hydrogen-rich fuels were investigated by varying the types of alumina supports, additives excluding platinum, and synthetic methods of impregnation and sol-gel synthesis. The reactions were conducted in the range of $25{\sim}300^{\circ}C$ over Pt, Co, and/or Na impregnated catalysts supported on commercial gamma-alumina, pseudoboehmite, or sol-gel derived xerogels. Catalytic activities were enhanced by cobalt addition due to strong Pt-Co interactions in the bimetallic phase. Additional sodium promoted not only the formation of the Pt-Co bimetallic interphase but also oxygen adsorption capability, giving rise to increase in the CO oxidation rate at lower temperatures. Moreover, chemical interaction between Pt and Co was considerably enhanced by sol-gel synthesis.

• Journal of Hydrogen and New Energy
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• v.27 no.5
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• pp.503-509
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• 2016

Fuel cell is a device for producing electricity by using the hydrogen produced by the fuel processor. At this time, CO is also created by the fuel processor. The resulting CO enters the stack where is produce electricity and leads to the adsorption of anode catalyst, finally the CO poisoning occurs. Stack which occurred CO poisoning has a reduction in performance and shelf life are gradually fall because they do not respond to hydrogen. In this paper, experiments that using a PROX reactor to prevent CO poisoning were carried out for removing the CO concentration to less than 10ppm range available in the fuel cell. Furthermore experiments by the PROX reaction was designed and manufactured with a water-cooling heat exchange reactor to maintain a suitable temperature control due to the strong exothermic reaction.