• Carbon letters
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• v.12 no.1
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• pp.39-43
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• 2011

Synthesis of carbon fibers from cotton fiber by pyrolysis process has been described. Synthesis parameters are optimized using Taguchi optimization technique. Synthesized carbon fibers are used for studying hydrogen adsorption capacity using Seivert's apparatus. Transmission electron microscopy analysis and X-ray diffraction of carbon fiber from cotton suggested it to be very transparent type material possessing graphitic nature. Carbon synthesized from cotton fibers under the conditions predicted by Taguchi optimization methodology (no treatment of cotton fiber prior to pyrolysis, temperature of pyrolysis $800^{\circ}C$, Argon as carrier gas and paralyzing time for 2 h) exhibited 7.32 wt% hydrogen adsorption capacity.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.365-368
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• 2002

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.2
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• pp.250-258
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• 2020

This study was conducted to analyze the impact of low level bio-alcohols that can be applied without modification of vehicles to improve air quality in Korea. The emissions and fuel economy of low level bio-alcohols mixed gasoline fuels of spark ignition vehicles, which are direct injection and port fuel injection, were studied in this paper. As a result of the evaluation, the particle number (PN) was reduced in all evaluation fuels compared to the sub octane gasoline without oxygen, but the correlation with the PN due to the increase in the oxygen content was not clear. In the CVS-75 mode, emitted CO tended to decrease compared to sub octane gasoline, but no significant correlation was found between NMHC, NOx and fuel economy. In addition, it was found that the aldehyde increased in the oxygenated fuel, and there was no difference in terms of the amount of aldehyde generated among a series of bio-alcohol mixed fuels.

• Journal of Energy Engineering
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• v.15 no.2 s.46
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• pp.96-106
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• 2006

Among several different hydrogen production technologies, solar hydrogen system for water splitting is the only clean and sustainable energy supplier. Hydrogen production by water-splitting utilizing solar energy has attracted considerable interest since the pioneering work of Honda and Fujishima in 1979, who discovered that water can be photo-electrochemically decomposed into hydrogen and oxygen using a semiconductor ($TiO_2$) electrode under UV irradiation. Most efforts to utilize solar ray lead to explore visible responding photocatalysts, PEC cells and other fusion technology like bio-photocatalytic conversion. In this paper, photon utilization technologies for water splitting have been briefly reviewed except solar thermal utilization technology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.683-687
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• 2006

This research investigated the effect of aeration pretreatment for anaerobic seed sludge on hydrogen production. Aeration time for anaerobic sludge was maintained at 0, 1, 3, 6, 12, and 24 hours in batch tests. Two continuous anaerobic reactors (aerated and non-aerated) were also operated. All experiments were conducted at $35^{\circ}C$ using mineral salts-glucose (20 g/l) medium. Methane production decreased with the increase in aeration time. Aeration for 6 hours was determined as an optimum from the amount of hydrogen produced. Hydrogen was steadily produced in the continuous reactor seeded with aerated sludge while no methane production was observed. However, small amount of hydrogen was produced in the non-aerated reactor for short period of time from the start even though short HRT (2 days) and low pH (5.5) were maintained.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.205.1-205
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• 2005

• Clean Technology
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• v.29 no.3
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• pp.163-171
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• 2023

Hydrogen has been gaining a lot of attention as a possible clean energy source that can aid in reaching carbon neutrality. Currently, hydrogen production has relied on the steam reforming of fossil fuels. However, due to the carbon dioxide emissions caused by this process, hydrogen production based on the steam reforming of bio-oil derived from biomass has been proposed as an alternative approach. In order to use this alternative approach efficiently, one of the key issues that must be overcome is that the complexity of bio-oil, which has a large molecular weight and diverse functional groups of hydrocarbons, promotes the catalytic deactivation of nickel-based catalysts. In this review, research efforts to improve nickel-based catalysts for the steam reforming of bio-oil have been discussed in terms of the active phase, support, and promoters. The active phases are involved in activating C-C and C-H bonds of high-molecular-weight hydrocarbons, and noble and transition metals can be utilized. In terms of the support and promoters, the catalytic deactivation of Ni-based catalysts can be inhibited by utilizing reactive lattice oxygen for support or by suppressing the acidity. The development of active and stable Ni-based reforming catalysts plays a critical role in clean hydrogen production based on bio-oils.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.94-100
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• 2016

Hydrogen production via steam reforming of bio-oil from algal biomass over fast pyrolysis with commercial catalysts was carried out. Aqueous bio-oil obtained by phase separation from a crude oil over fast pyrolysis was used as a reactant and comparison studies for activity over different catalysts (FCR-4-02, POS-7, Cat. A, RUA), reaction temperature, and steam/carbon (S/C) ratios were performed. Experimental results showed that different catalytic activities were observed with different S/C ratios and catalyst composition and the highest hydrogen yield of 70% was obtained with a POS-7 catalyst at a S/C ratio of 10 and 1073 K.

• Journal of the Korean Magnetic Resonance Society
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• v.25 no.4
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• pp.64-69
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• 2021

In the developed NMR hyperpolarization techniques, Signal amplification by reversible exchange (SABRE) technique is thought to be a promising method to overcome the low sensitivity of bio-NMR/MRI. Most experiments using SABRE have been done in methanol, which is biologically harmful solvent. Therefore, more biological friendly solvent, such as ethanol can be more appropriate solvent to be applicable in bio-NMR and MRI. As the proof of concept, successful hyperpolarization on pyridine via SABRE is carried out in ethanol and its enhancement factor is calculated to be more than 150 folds. To investigate more about its possibility of hyperpolarization in different alcohol solvents, methanol and propanol are used for SABRE in the same condition. The overall polarization trend in different external magnetic field is similar but its polarization number is decreased with higher molecular weight solvents (the order from methanol to propanol). This result indicates that the efficiency of SABRE is different from solvent system despite its same functional group and similar properties. Higher para-hydrogen concentration, higher partial pressure of para-hydrogen, and deuterated solvent can increase the hyperpolarization in any solvents. With these series of successful SABRE results, future studies on SABRE in more biofriendly environment, on more various solvent systems, and with more substrates are needed and it will be the firm basis for applying the SABRE system on the future bio-NMR/MRI.

• KSBB Journal
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• v.20 no.6
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• pp.408-412
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• 2005

In a previous research, it has been found that it could be possible to increase the partial pressure of hydrogen and hydrogen yield by scavenging the $CO_2$ from the heads pace of reactor. In this research, the positive and negative effects of the $CO_2$ scavenging especially on the fate of by-products were investigated by a batch experiment. Production and conversion of by-products had critical relationships with hydrogen evolution and consumption. The maximum hydrogen fraction in the headspace was increased from 66.4 to 91.2% by removing the $CO_2$ in the headspace and the degradation rate of glucose was also enhanced. The removal of $CO_2$ effectively hindered the homoacetogenesis but caused several negative phenomena. The degradation of ethanol, one of the main products, was inhibited by the high partial pressure of hydrogen and/or the absence of $CO_2$. Also it was observed that other by-products such as propionate, propanol, acetone, etc. could not be degraded further after produced from glucose. On the other hand, solventogenesis was not observed in spite of the high hydrogen partial pressure apart from previous researches and it might hinder the excess production of acetate, which could cause overall inhibition. From this research, it could be implicated that the $CO_2$ scavenging method could be recommended if the fermentation was purposed to produce hydrogen and ethanol.