• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.158.1-158.1
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• 2011

In this work, we prepared ultramicroporous carbons (UC) prepared by pyrolyzing poly(vinylidene fluoride) with different carbonization temperatures, and investigated the hydrogen storage behaviors. The surface functional groups and specific elements of UC were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), respectively. Textural properties were analyzed using $N_2$ adsorption isotherms at 77 K. The hydrogen storage capacity of the UC samples were investigated by BEL-HP at 298 K/10 MPa. From the results, it was found that the hydrogen storage capacity was enhanced with increasing of specific surface area, resulting from the formation of ultramicropore on the UC.

• Carbon letters
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• v.5 no.4
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• pp.186-190
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• 2004

In this work, a nickel metal (Ni) electroplating on the activated carbon fiber (Ni/ACFs) surfaces was carried out to remove the toxic hydrogen chloride (HCl) gas. The surface properties of the treated ACFs were determined by using nitrogen adsorption isotherms at 77 K, SEM, and X-ray diffraction (XRD) measurements. HCl removal efficiency was confirmed by a gas-detecting tube technique. As a result, the nickel metal contents on the ACF surfaces were increased with increasing the plating time. And, it was found that the specific surface area or the micropore volume of the ACFs studied was slightly decreased as increasing the plating time. Whereas, it was revealed that the HCl removal efficiency containing nickel metal showed higher efficiency values than that of untreated ACFs. These results indicated that the presence of nickel metal on the ACF surfaces played an important role in improving the HCl removal over the Ni/ACFs, due to the catalytic reactions between nickel and chlorine.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.105-113
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• 1994

The amount of nitrogen gas adsorbed by Spherocarb and Sucrose Char was measured as a function of the relative pressure with temperature being kept constant at 77 to 184K. Isotherms at different temperatures were obtained by keeping the adsorbent at a constant temperature using liquid nitrogen, iso-pentane, n-pentane, ethyl alcohol, and iso-propyl alcohol slush baths. The objective for this study is to provide information on the specific surface area and pore volume by analyzing the experimental data using adsorption models such as the Brunauer-Emmett-Teller and Dubinin-Radushkevich models.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.95-109
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• 2017

There are several contributions to the gas load of a system of which often the most important is outgassing. Adsorption occurs via two main processes, physisorption and chemisorption, and can be described using five (or six) classifying isotherms. Outgassing is the result of desorption of previously adsorbed molecules, bulk diffusion, permeation and vapourisation. Looking at the desorption rate, pumping speed and readsorption on surfaces, the net outgassing of the system can be calculated. There is significant variation in measured outgassing rates between different materials but also between published rates for the same materials, in part due to the number of different methods used to measure outgassing. This article aims to review the outgassing process, outgassing rates, measurement methods and techniques that can be used to reduce the outgassing of a system.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.477-480
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• 2002

A new microporous TiO2-pillared layered titanate has been successfully prepared by hybridizing the exfoliated titanate with the anatase TiO2 nano-sol. According to the X-ray diffraction analysis and N2 adsorption-desorption isotherms, the TiO2-pillared layered titanate showed a pillar height of ~2 nm with a high surface area of ~460 m2/g and a pore size of ~0.95 nm, indicating that a microporous pillar structure is formed. Its photocatalytic activity was evaluated by measuring the photodegradation rate of 4-chlorophenol during irradiation of catalyst suspensions in an aqueous solution. An enhancement in activity of ca. 170% was obtained for TiO2-pillared layered titanate compared to that of the pristine compound such as layered cesium titanate.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.627-627
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• 2009

In this work, the activated carbons (ACs) with high porosity were synthesized from pitch by KOH chemical activation. The structure and surface properties of ACs were characterized by means of elemental analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy(XPS). And, the influence of the KOH-to-pitch ratio on the porosity of the ACs was investigated using the nitrogen adsorption isotherms at 77 K and a scanning electron microscopy (SEM). As a result, pitch could be successfully converted into ACs with well-developed micro and mesopores. The specific surface areas and pore volumes were increased with an increase of the KOH-to-pitch ratio. Furthermore, it was found that the addition of KOH led to the transformation of the micropores to the meso- and macropores. In the application to electric double layer capacitors (EDLC), the pitch-based ACs showed a higher capacitance per weight and per volume, and an excellent electrochemical stability in the high voltage region.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.231-231
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• 2009

In this work, we prepared the Ni-loaded porous SBA-15 (SBA-15) by a depositionprecipitation (D-P) method, in order to enhance the hydrogen storage capacity. The structure and morphology of the Ni/SBA-15 were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). The results showed that, at the Ni loading used at the DP times in the range of 0-120 min, SBA-15 preserved the well-ordered hexagonal porous arrangement. The textural properties of the Ni/SBA-15 were analyzed using N2 adsorption isotherms at 77 K. Specific surface area and mesopore volume of the samples were determined from the Brunauer-Emmett-Teller (BET) equation and Barrett-Joiner-Halenda (BJH) method, respectively. The hydrogen storage capacity of the Ni/SBA-15 was evaluated at 298 K/10 MPa. The hydrogen storage capacity of the Ni/SBA-15 was increased in accordance with Ni content. Consequently, it was found that the presence of Ni on mesoporous SBA-15 created hydrogen-favorable sites which enhanced the hydrogen storage capacity by spillover effect.

• Computers and Concrete
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• v.16 no.5
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• pp.775-793
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• 2015

Moisture transport in concrete in atmospheric environment was studied in this paper. Based on the simplified formula of the thickness of the adsorbed layer, the pore-size distribution function of cement paste was calculated utilizing the water adsorption isotherms. Taking into consideration of the hysteresis effect in cement paste, the moisture diffusivity of cement paste was obtained by the integration of the pore-size distribution. Concrete is regarded as a two-phase composite with cement paste and aggregate, neglecting the moisture diffusivity of aggregate, then moisture diffusivity of concrete was evaluated using the composite theory. Finally, numerical simulation of humidity response during both wetting and drying process was carried out by the finite difference method of partial differential equation for moisture transport, and the numerical results well capture the trend of the measured data.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.782-784
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• 2008

Ag/Ni bimetallic cluster loading on porous carbon fibers was accomplished in order to enhance the HCl removal efficiency of the carbons. The surface properties of the Ag/Ni/carbons were determined by XRD and SEM. N2/77 K adsorption isotherms were investigated using BET and Boers t-plot methods. The HCl removal efficiency was confirmed by a gas chromatography technique, and it was found that that efficiency was predominantly improved in the presence of Ag/Ni clusters compared with the efficiencies of the as-received and single-metal-plated carbons. This indicates that synergetic reactions exist between Ag/Ni and HCl gas, resulting in advanced HCl removal capacity of porous carbons.

• Clean Technology
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• v.8 no.2
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• pp.93-99
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• 2002

Adsorption dynamics for toluene and trichloroethylene with an isothermal fixed bed of activated carbon fiber were investigated. Equilibrium isotherms were measured by a static method for toluene and trichloroethylene onto activated carbon fiber at temperatures of 298, 323, and 348 K and pressure up to 3 kPa for toluene and 6 kPa for trichloroethylene, respectively. These results were correlated by the Toth equation. And dynamic experiments in an isothermal condition of 298 K were examined. Breakthrough curves reflected the effects of the experimental variables such as partial pressures for adsorbate and interstitial bulk velocities of gas flow. To present the column dynamics, a dynamic model based on the linear driving force (LDF) mass transfer model was applied.