In this work, highly porous carbons were prepared by chemical activation of carbonized biomass-derived aerogels. These aerogels were synthesized from watermelon flesh using a hydrothermal reaction. After carbonization, chemical activation was conducted using potassium hydroxide to enhance the specific surface area and microporosity. The micro-structural properties and morphologies were measured by X-ray diffraction and scanning electron microscopy, respectively. The specific surface area and microporosity were investigated by N2/77 K adsorption-desorption isotherms using the Brunauer-Emmett-Teller method and Barrett-Joyner-Halenda equation, respectively. Hydrogen storage capacity was dependent on the activation temperature. The highest capacity of 2.7 wt% at 77 K and 1 bar was obtained with an activation temperature of 900°C.

TiCoxFe1-x(x=0.50~1.00)계 합금을 제조하고, 합금의 특성을 X-ray diffractometer (XRD), pressure composition temperature (PCT)곡선, scanning electron microscopy (SEM)에 의해 조사하였고, TiCoxFe1-x(x=0.50~1.00)-stainless steel (SS) 복합막에 대해 H2-N2 혼합기체분리실험을 하였다. X-선 회절분석에 의하면 TiCoxFe1-x(x=0.50~1.00)계 합금의 결정구조는 TiCo와 같은 입방정구조이었다. TiCoxFe1-x(x=0.50~1.00)계 합금은 120°C에서 hysteresis현상을 나타내었고, 합금 중 Fe의 양이 증가함에 따라 x=0.90~1.00과 0.50~0.55 범위에서는 hysteresis가 증가하였고, x=0.55~0.90 범위에서는 감소하였다. 가장 작은 hysteresis를 나타낸 합금은 TiCo0.55Fe0.45이었다. 120°C에서 TiCoxFe1-x(x=0.50~1.00)-SS 복합막의 수소투과압력의 최저값은 TiCo0.55Fe0.45에서 2.5 atm을 나타내었고, 최대값은 TiCo0.90Fe0.10에서 10 atm을 나타내었다. TiCoxFe1-x(x=0.50~.00)-SS 복합막에 의하여 120°C에서 H2-N2 혼합기체를 분리하는 경우, 가장 우수한 복합막은 고압부의 수소투과압력이 2.5 atm으로 가장 낮고, hysteresis가 가장 작은 TiCo0.55Fe0.45-SS 복합막이었다.

PTMSP와 PDMS로부터 합성된 PTMSP/PDMS 그라프트 공중합체에 다공성 borosilicate를 0~5 wt% 첨가하여 PTMSP/PDMS-borosilicate 복합막을 제조하였다. 합성된 PTMSP/PDMS 그라프트 공중합체의 수평균분자량(Mn)은 460,000이었 고, 중량평균분자량(Mw)은 570,000이었으며, 유리전이온도(Tg)는 33.53°C에서 나타났다. TGA 측정에 의하면 PTMSP/PDMS에 borosilicate가 첨가되면 복합막의 감량이 작아지고 감량이 완결되는 온도도 낮아졌다. SEM측정에 의하면 PTMSP/PDMS-borosilicate 복합막 내에 들어있는 borosilicate는 1~5 μm 크기로 분산되어 있었다. 기체투과 실험에 의하면 PTMSP/PDMS-borosilicate가 첨가되면서 자유부피, 공동, 기공률이 증가하여 기체투과가 용해확산에 의한 것보다 분자체거름, 표면확산, Knudsen 확산에 의해 일어나는 경우가 점차 증가하여 H2와 N2의 투과도는 증가하고 선택도(H2/N2)는 감소하였다

졸겔법에 의해서 trimethylborate (TMB)/tetraethylorthosilicate (TEOS) 몰비 0.01, 온도 800°C에서 SiO2⋅B2O3가 제조되었다. 그리고 제조된 SiO2⋅B2O3와 PDMS[poly(dimethylsiloxane)]로부터 PDMS-SiO2⋅B2O3 복합막을 제조하고 막의물리화학적 특성을 TG-DTA, FT-IR, BET, X-ray, SEM에 의해 조사하고 그리고 H2와 N2의 투과도와 선택도를 조사하였다.TG-DTA, BET, X-ray, FT-IR 측정에 의하면 SiO2⋅B2O3는 무정형의 다공성 SiO2⋅B2O3였으며, 기공의 평균직경은 37.7821Å, 표면적은 247.6868 m2/g이었다. TGA 측정에 의하면 PDMS 내에 SiO2⋅B2O3가 첨가되었을 때 PDMS-SiO2⋅B2O3 복합막의 열적 안정성은 향상되었다. SEM 관찰에 의하면 SiO2⋅B2O3는 약 1 μm 크기로 PDMS 내에 덩어리 상태로 뭉쳐서 분산되어 있었다. 기체투과실험에 의하면 PDMS 내에 SiO2⋅B2O3 함량이 증가하면 H2와 N2의 투과도는 증가하였고,

To improve its textural properties as a support for platinum catalyst, carbon aerogel was chemically activated with KOH as a chemical agent. Carbon-supported platinum catalyst was subsequently prepared using the prepared carbon supports(carbon aerogel(CA), activated carbon aerogel(ACA), and commercial activated carbon(AC)) by an incipient wetness impregnation. The prepared carbon-supported platinum catalysts were applied to decalin dehydrogenation for hydrogen production. Both initial hydrogen evolution rate and total hydrogen evolution amount were increased in the order of Pt/CA < Pt/AC < Pt/ACA. This means that the chemical activation process served to improve the catalytic activity of carbon-supported platinum catalyst in this reaction. The high surface area and the well-developed mesoporous structure of activated carbon aerogel obtained from the activation process facilitated the high dispersion of platinum in the Pt/ACA catalyst. Therefore, it is concluded that the enhanced catalytic activity of Pt/ACA catalyst in decalin dehydrogenation was due to the high platinum surface area that originated from the high dispersion of platinum.

Odor compounds and air-born microorganisms are simultaneously emitted from various aeration processes such as aerobic digestion, food-waste compositing, and carcass decomposition facilities that are biologically-treating wastes with high organic contents. The air streams emitted from these processes commonly contain sulfur-containing odorous compounds such as hydrogen sulfide(H2S) and bacterial bioaerosols. In this study, a wet-plasma method was applied to remove these air-born pollutants and to minimize safety issues. In addition, the effects of a gas retention time and a liquid-gas ratio were evaluated on removal efficiencies in the wet-plasma system. At the gas reaction time of 1.8 seconds and the liquid-gas ratio of 0.05 mLaq/Lg, the removal efficiency of bioaerosol was approximately 75 %, while the removal efficiency of H2S was lower than 20 %, indicating that the gaseous compound was not effectively oxidized by the plasma reaction at the low liquid addition. When the liquid-gas ratio was increased to 0.25 mLaq/Lg, the removal efficiencies of both H2S and bioaerosol increased to greater than 99 %. At the higher liquid-gas ratio, more ozone was generated by the wet-plasma reaction. The ozone generation was significantly affected by the input electrical energy, and it needed to be removed before discharged from the process.

Benzene was oxidized by binary oxidants composed of nitric acid and hydrogen peroxide at 80℃. The product obtained was analyzed with gas chromatograph-mass spectrometer. Eight high value compounds, 2-nitrophenol, 2-chloro-6-nitrophenol, 4-chloro-2- nitrophenol, 2-chloro-4-nitrophenol, 2,4-dinitrophenol, 4-nitrophenol, 2,6-dinitrophenol and 2-chloro-4,6-dinitro-phenol were found, which they have high contents in the range from 4.28% to 32.52%. These compounds are very widely used in organic synthesis. e.g., synthesizing dye, medicines and chemical reagents, pesticide, explosive, polymer, etc.

The contents of this paper is to develop a passive sampler for H2S measurement. When the H2S gas exists in the air, AgNO3 solution coated filter of white used phenomenon which is exchanged with black. If the H2S gas concentration increased, the color of AgNO3 solution coated filter is discolored more black. H2S passive sampler measures the H2S gas concentration by changed color of AgNO3 solution coated filter. The reproducibility of the H2S passive sampler is very stable to within an error 5%RSD. The black color of AgNO3 solution coated filter showed a linear relationship with the H2S gas concentrations. In addition, correlation of the developed CDM and CR-10(Minolta, Japan) showed a high correlation to 0.99. Manufactured H2S passive sampler must be kept refrigerated, stability and reactivity was observed for up to 20 days

무정형의 괴상의 다공성 borosilicate는 trimethylborate (TMB)/ tetraethylorthosilicate (TEOS) 몰비 0.01∼0.10 겔 체를 700∼800°C 온도범위에서 열처리 하였을 때 얻어졌다. BET와 SEM 관찰에 의하면 700∼800°C에서 얻어진 borosilicate의 표면적은 251.12∼355.62 m2/g이고, 기공직경은 3.5∼4.9 nm이며, 입자크기는 30∼60 nm이었다. TGA측정에 의 하면 borosilicate가 poly[1-(trimethylsilyl)propyne](PTMSP)에 첨가되었을 때 PTMSP-borosilicate 복합막의 열적 안정성은 향 상 되었다. SEM관찰에 의하면 borosilicate는 1 μm 크기로 복합막 내에 분산되어 있었다. 기체투과실험에 의하면 PTMSP에 borosilicate 함량이 증가하면 자유부피, 공동, 기공률이 증가하여 기체투과가 용해확산에 의한 것보다 분자체거름, 표면확산, Knudsen 확산에 의해 일어나는 경우가 점차 증가함으로 해서 H2와 N2의 투과도는 증가하고 선택도(H2/N2)는 감소하였다.

In this study, the reduction kinetics and behaviors of oxides in the water-atomized iron powder have been evaluated as a function of temperature ranging 850-1000˚C in hydrogen environment, and compared to the reduction behaviors of individual iron oxides including Fe2O3, Fe3O4 and FeO. The water-atomized iron powder contained a significant amount of iron oxides, mainly Fe3O4 and FeO, which were formed as a partially-continuous surface layer and an inner inclusion. During hydrogen reduction, a significant weight loss in the iron powder occurred in the initial stage of 10 min by the reduction of surface oxides, and then further reduction underwent slowly with increasing time. A higher temperature in the hydrogen reduction promoted a high purity of iron powder, but no significant change in the reduction occurred above 950˚C. Sequence reduction process by an alternating environment of hydrogen and inert gases effectively removed the oxide scale in the iron powder, which lowered reduction temperature and/or shortened reduction time.

Hydrogen energy is expanding in range for civil use together with development of pollution-free power sources recently, and it is judged that the use of hydrogen will increase more as a part of carbon dioxide reduction measures according to the Climatic Change Convention. Especially, it is thought that the securement of safety of the used dispenser will be the biggest obstacle in the use of high-pressure hydrogen because the hydrogen station is operated in a high pressure. This study found risks in the process and problems on operation by making use of HAZOP(6 kinds), a qualitative safety evaluation technique, and FMEA(5 kinds), a fault mode effect analysis, for the hydrogen charging system at a hydrogen gas station, derived 6 risk factors from HAZOP and 5 risk factors from FMEA, and prepared measures for it.

For the hydrogen economy system being tried starting with the 21st century, the fields that was not dealt with so far, such as the safety measure for large leakage accidents, the safety problem at infrastructures like a hydrogen station, the safety problem in terms of automobiles depending on introduction of hydrogen cars, the safety problem in a supply for homes like fuel cells, etc., are being deeply reviewed. In order to establish a safety control system, an essential prerequisite in using and commercializing hydrogen gas as an efficient energy source, it is necessary to conduct an analysis, such as analysis of hydrogen accident examples, clarification of physical mechanisms, qualitative and quantitative evaluation of safety, development of accident interception technologies, etc. This study prepared scenarios of hydrogen gas leakage that can happen at hydrogen stations, and predicted damage when hydrogen leaks by using PHAST for this.

The existing metal getters are invariably covered with thin oxide layers in air and the native oxide layer must be dissolved into the getter materials for activation. However, high temperature is needed for the activation, which leads to unavoidable deleterious effects on the devices. Therefore, to improve the device efficiency and gas-adsorption properties of the device, it is essential to synthesize the getter with a method that does not require a thermal activation temperature. In this study, getter material was synthesized using palladium oxide (PdOx) which can adsorb H2 gas. To enhance the efficiency of the hydrogen and moisture absorption, a porous layer with a large specific area was fabricated by an etching process and used as supporting substrates. It was confirmed that the moisture-absorption performance of the SiO2/Si was characterized by water vapor volume with relative humidity. The gas-adsorption properties occurred in the absence of the activation process.

In this study, highly sensitive hydrogen micro gas sensors of the multi-layer and micro-heater type were designed and fabricated using the micro electro mechanical system (MEMS) process and palladium catalytic metal. The dimensions of the fabricated hydrogen gas sensor were about 5mm×4mm and the sensing layer of palladium metal was deposited in the middle of the device. The sensing palladium films were modified to be nano-honeycomb and nano-hemisphere structures using an anodic aluminum oxide (AAO) template and nano-sized polystyrene beads, respectively. The sensitivities (Rs), which are the ratio of the relative resistance were significantly improved and reached levels of 0.783% and 1.045 % with 2,000 ppm H2 at 70˚C for nano-honeycomb and nano-hemisphere structured Pd films, respectively, on the other hand, the sensitivity was 0.638% for the plain Pd thin film. The improvement of sensitivities for the nano-honeycomb and nano-hemisphere structured Pd films with respect to the plain Pd-thin film was thought to be due to the nanoporous surface topographies of AAO and nano-sized polystyrene beads.

Blends of poly(vinyl alcohol) (PVA), polyethyleneimine (PEI), and graphene oxide (GO) were prepared by solution casting method. Calorimetric thermal properties of the blends were investigated. The Tgs of PVA/PEI blends were higher than the Tgs of either of the component polymers at low concentrations of PEI. These abnormal increases of Tgs may be due to the negative entropy of mixing which is associated with strong hydrogen bonding between PVA and PEI. The degree of depression of T0ms was not reduced by the negative entropy of mixing, since strong hydrogen bonding also causes an increase in the magnitude of negative χ between PVA and PEI. The Tg of PVA was increased significantly by adding 0.7 wt.% GO into PVA. The magnitude of negative χ was increased by adding GO into the blends of PVA and PEI.

NiO catalysts were successfully coated onto FeCrAl metal alloy foam as a catalyst support via a dip-coating method. To demonstrate the optimum amount of NiO catalyst on the FeCrAl metal alloy foam, the molar concentration of the Ni precursor in a coating solution was controlled, with five different amounts of 0.4 M, 0.6 M, 0.8 M, 1.0 M, and 1.2 M for a dip-coating process. The structural, morphological, and chemical bonding properties of the NiO-catalyst-coated FeCrAl metal alloy foam samples were assessed by means of field-emission scanning electron microscopy(FESEM), scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). In particular, when the FeCrAl metal alloy foam samples were coated using a coating solution with a 0.8 M Ni precursor, well-dispersed NiO catalysts on the FeCrAl metal alloy foam compared to the other samples were confirmed. Also, the XPS results exhibited the chemical bonding states of the NiO phases and the FeCrAl metal alloy foam. The results showed that a dip-coating method is one of best ways to coat well-dispersed NiO catalysts onto FeCrAl metal alloy foam.

Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission elec-tron microscopy (HRTEM) revealed a densely packed high surface area of SP2-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and ther-mal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.

In this study, nano-scale copper powders were reduction treated in a hydrogen atmosphere at the relativelyhigh temperature of 350℃ in order to eliminate surface oxide layers, which are the main obstacles for fabricating anano/ultrafine grained bulk parts from the nano-scale powders. The changes in composition and microstructure beforeand after the hydrogen reduction treatment were evaluated by analyzing X-ray diffraction (XRD) line profile patternsusing the convolutional multiple whole profile (CMWP) procedure. In order to confirm the result from the XRD lineprofile analysis, transmitted electron microscope observations were performed on the specimen of the hydrogen reduc-tion treated powders fabricated using a focused ion beam process. A quasi-statically compacted specimen from the nano-scale powders was produced and Vickers micro-hardness was measured to verify the potential of the powders as thebasis for a bulk nano/ultrafine grained material. Although the bonding between particles and the growth in size of theparticles occurred, crystallites retained their nano-scale size evaluated using the XRD results. The hardness results dem-onstrate the usefulness of the powders for a nano/ultrafine grained material, once a good consolidation of powders isachieved.

Pure MgH2 was milled under a hydrogen atmosphere (reactive mechanical grinding, RMG). The hydrogen storage properties of the prepared samples were studied at a relatively low temperature of 423 K and were compared with those of pure Mg. The hydriding rate of the Mg was extremely low (0.0008 wt% H/min at n = 4), and the MgH2 after RMG had higher hydriding rates than that of Mg at 423 K under 12 bar H2. The initial hydriding rate of MgH2 after RMG at 423 K under 12 bar H2 was the highest (0.08 wt% H/min) at n = 2. At n = 2, the MgH2 after RMG absorbed 0.39 wt% H for 5 min, and 1.21 wt% H for 60 min at 423K under 12 bar H2. At 573 K under 12 bar H2, the MgH2 after RMG absorbed 4.86 wt% H for 5 min, and 5.52 wt% H for 60 min at n = 2. At 573 K and 423 K under 1.0 bar H2, the MgH2 after RMG and the Mg did not release hydrogen. The decrease in particle size and creation of defects by reactive mechanical grinding are believed to have led to the increase in the hydriding rate of the MgH2 after RMG at a relatively low temperature of 423 K.

Freeze drying of a porous Cu-Sn alloy with unidirectionally aligned pore channels was accomplished by using a composite powder of CuO-SnO2 and camphene. Camphene slurries with CuO-SnO2 content of 3, 5 and 10 vol% were prepared by mixing with a small amount of dispersant at 50˚C. Freezing of a slurry was done at -25˚C while the growth direction of the camphene was unidirectionally controlled. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green bodies were hydrogen-reduced at 650˚C and then were sintered at 650˚C and 750˚C for 1 h. XRD analysis revealed that the CuO-SnO2 powder was completely converted to Cu-Sn alloy without any reaction phases. The sintered samples showed large pores with an average size of above 100μm which were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores. The size of the large pores decreased with increasing CuO-SnO2 content due to the change of the degree of powder rearrangement in the slurry. The size of the small pores decreased with increase of the sintering temperature from 650˚C to 750˚C, while that of the large pores was unchanged. These results suggest that a porous alloy body with aligned large pores can be fabricated by a freeze-drying and hydrogen reduction process using oxide powders.