• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.662-668
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• 1989

The decomposition reaction of hydrogen peroxide was carried out by using metal-4,4',4",4"'-tetraaminophthalocyanine [Mt-$PcNH_2$, Mt = Fe(III), Co(II)] supported on poly (styrene-co-methacrylic acid), in heterogeneous aqueous system. These catalysts showed a catalse-like activity and Fe(III)-$PcNH_2$ supported on the copolymer was particularly effective for the decomposition of hydrogen peroxide. It was found that the rate of decomposition increased smoothly in the higher pH region and catalytic reaction was interfered by adding $CN^-,\;CNS^-,\;{C_2O_4}^{-2},\;I^-$ ions. The kinetics of the catalytic reaction was also investigated and the reaction proceeds according to the Michaelis-Menten type mechanism.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.357-365
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• 2008

Hydrogen energy becomes more attractive in that it can resolve the exhaustion of fossil fuels and their environmental problems. Until now, water electrolysis has been a interesting technique to produce hydrogen from non-fossil fuels. In principle, water electrolysis is an environmentally friendly technique to split water into hydrogen and oxygen, so that it can be utilized without any limitation of resources. Herein, we introduce basic understanding and three types of water electrolysis. Furthermore, the research trend and patent analysis will be followed along with an outlook.

• Prospectives of Industrial Chemistry
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• v.24 no.2
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• pp.1-9
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• 2021

플라스틱은 가볍고 물성이 뛰어나며 가공이 용이하면서도 낮은 가격 때문에 우리의 실생활에서 매일 사용되고 있다. 동시에 썩지 않는 특성 탓에 폐플라스틱에 의한 환경오염의 문제가 심해짐에 따라 전 세계적으로 일회용 포장재 및 용기에 사용되는 플라스틱의 사용을 금지하는 규제 및 폐플라스틱을 재활용하려는 시도가 늘어나고 있다. 하지만 인류가 지난 수십 년간 생산한 플라스틱은 약 83억 톤이지만 이중 약 10%정도만 재활용 되었을 정도로 폐플라스틱의 재활용 비율은 미비하다. 특히, 최근 코로나 팬데믹으로 인해 택배 및 배달음식 주문량이 늘어남에 따라 플라스틱의 사용량이 급증하여 폐플라스틱의 재활용 필요성은 더욱더 커지고 있다. 본 기고문에서는 불균일 촉매를 이용한 수소첨가 폐플라스틱의 분해에 관한 최신 연구동향을 다루고자 한다. 안정적이고 반응성 및 선택성이 뛰어난 촉매 개발은 폐플라스틱의 효과적인 분해를 위해서 매우 중요하다.

• Journal of Soil and Groundwater Environment
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• v.6 no.1
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• pp.3-12
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• 2001

During ozonation process, the hydroxyl radical generation rates were measured under different experimental conditions (ozone feed rate, nitrobenzene concentration, hydroxyl radical scavenger, pH, HO$_2$O$_2$/O$_3$ etc.) Nitrobenzene could be decomposed by hydroxyl radical rather than ozone only and nitrobenzene decomposition rate was expressed with functions of ozone and nitrobenzene concentration. The rate was decreased as the hydroxyl radical scavenger concentration was increased, and all results were followed pseudo first-order reaction. Using a competitive method, hydroxyl radical generation rate was measured with probe compound and scavenger. It was proportional to ozone concentration, and 0.24mo1 of hydroxyl radical was produced with 1mol of ozone. Under different pH conditions, hydroxyl radical generation rates were measured (pH 10.2 (0.91Ms$^{-1}$ ) > pH 7.3 (0.72Ms$^{-1}$ ) > pH 5.6 (0.67Ms$^{-1}$ ) > pH 3.4 (0.63Ms$^{-1}$ )) showing higher generation rate at high pH values. Addition of hydrogen peroxide promoted the generation rate of hydroxyl radical. Considering the results of pH experiments and addition of hydrogen peroxide experiments, the hydroxyl radical generation rate was 1.6 times higher in hydrogen peroxide solution than in high pH solution, indicating addition of hydrogen peroxide is better promoter to produce the hydroxyl radical in ozonation. These results could be applied to AOPs to remediate the contaminated wastewater and groundwater.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.165-170
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• 2017

An efficient synthetic process for bio-based adipic acid, a monomer for nylon 66, was developed from galactose. Galactaric acid, prepared from a mild oxidation of galactose using a Pt catalyst, was successfully converted to muconate, a key intermediate for adipic acid, by an efficient microwave-assisted DODH (deoxydehydration) reaction. The high efficiency of the microwave-assisted reaction greatly reduced the overall reaction time to 30 min. and resulted in an excellent yield of 97% of muconate. The catalytic hydrogenation of muconate followed by the acidic hydrolysis successfully produced the desired adipic acid in high purity after recrystallization.

• KSBB Journal
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• v.20 no.6
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• pp.393-400
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• 2005

Hydrogen($H_2$) as a clean, and renewable energy carrier will be served an important role in the future energy economy. Several biological $H_2$ production processes are known and currently under development, ranging from direct bio-photolysis of water by green algae, indirect bio-photolysis by cyanobacteria including the separated two stage photolysis using the combination of green algae and photosynthetic microorganisms or green algae alone, dark anaerobic fermentation by fermentative bacteria, photo-fermentation by purple bacteria, and water gas shift reaction by photosynthetic or fermentative bacteria. In this paper, biological $H_2$ production processes, that are being explored in fundamental and applied research, are reviewed.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.61-71
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• 2000

When irradiate the power ultrasound into the aqueous solutions, water vapor is decomposed by the heat of very high temperature in the cavitation bubble to produce OH (hydroxyl radical) and H (hydrogen radical), and these radicals play a role in decomposing the substances in aqueous solution by oxidation and/or reduction, and in producing the hydrogen peroxide. Accordingly it is possible to predict that the quantity of hydrogen peroxide produced may correlate with the sonolysis mechanism of the substance in aqueous solution. Thus to confirm this prediction, the quantities of hydrogen peroxide produced from each of the air saturated distilled water and three aqueous solutions of TCE, benzene, and 2,4-DCP that are prepared by dissolving them into distilled water are measured. As a result, it showed that the quantity of hydrogen peroxide produced from the distilled water and three aqueous solutions are increased in order of distilled water>TCE solution>2,4-DCP solution>benzene solution, and decrease with decrease in concentration of organic substance, which coincide with the sonolysis mechanisms reported that TCE in aqueous solution is decomposed directly by the pyrolysis in and around the cavitation bubbles when its concentration is high and by the radical reaction when low, however, benzene and 2,4-DCP are decomposed not only by the pyrolysis but also by the radical reactions. Effects of such experimental parameters as the acoustic frequency and power and as the concentration showed that the higher the acoustic frequency and the lower the acoustic power, the less the quantity of hydrogen peroxide was produced. This result coincide with the theory of ultrasound for the relation between the cavitation that is the energy source of the power ultrasound in aqueous solution and these experimental parameters.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.111-116
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• 2015

Practical difficulty in the HDDR (hydrogenation - disproportionation - desorption - recombination) processing of Nd-Fe-B-type alloy is a poor reproducibility of coercivity of the HDDR-treated material. In an attempt to improve the reproducibility of coercivity of the HDDR-treated $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy, the hydrogen decrepitation was carefully controlled so as to induce more extensive micro-cracks in the particle. Prior to the hydrogenation and disproportionation reaction of HDDR processing, an additional hydrogen degassing was carried out at an elevated temperature of $600^{\circ}C$ under vacuum for the previously hydrogen decrepitated particle. During the additional hydrogen degassing the lattice of hydrogen absorbed $Nd_2Fe_{14}B$ phase was further shrunken, hence more microcracks were introduced in the particle due to its brittle nature. Particles with more micro-cracks had more homogeneous hydrogen absorption and desorption reaction during the HDDR-treatment. The improved reproducibility of coercivity of the HDDR-treated material was attributed to the improved homogeneity of the HDDR reactions due to the presence of more micro-cracks.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.675-682
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• 2005

Al containing mesoporous molecular sieve (Al-MMS) was synthesized by hydrolysis of $H_2SiF_6$ and $Al(NO_3)_3{\cdot}9H_2O$. The material obtained was characterized by XRD, $N_2$-physisorption. The specific surface area was $981m^2/g$, and the average pore size was uniformity $39{\AA}$. It was confirmed that the acidity of Al-MMS was milder than that of zeolite Y based on the results of $NH_3$-TPD. Active materials, Pt and Pd, were loaded on Al-MMS in order to examine the feasibility of using Al-MMS as a catalyst support in the hydrogenation of aromatic compounds included in the residue oil of a naphtha cracker. The hydrogenation activity of PtPd/Al-MMS has been studied by following the kinetics of the hydrogenation of naphthalene, and by comparing the kinetic parameters obtained with Pt and Pd catalysts supported on the other mesoporous material support and commercial conventional support materials. PtPd/Al-MMS catalyst shows the highest activity of hydrogenation and sulfur resistance. The high activity of PtPd/Al-MMS was confirmed again in the hydrogenation of PGO (pyrolized gas oil), which is residue oil obtained from a naphtha cracker. Therefore, PtPd/Al-MMS can be applied to the hydrogenation of aromatic compounds included in the residue oil of a commercial naphtha cracker commericially.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.414-416
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• 2002

폴리비닐알코올 (poly(vinyl alcohol), PVA)는 분해되어 대부분의 성분이 물과 이산화탄소로 전환되는 가장 이상적인 환경친화성 고분자이다. PVA만의 특유한 반응인 비누화 과정에 의해 가지가 모두 제거되기 때문에 화학적인 방법에 의해 완벽한 선형고분자를 얻는 것이 가능하다. PVA는 측쇄에 존재하는 히드록시기의 강력한 수소결합 때문에 우수한 반응성 및 결합성을 보유한 유기 고분자로서, 수용성 뿐 아니라 다양한 소재와 상용성이 있는 것으로 알려져 있다(1-4). (중략)