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김도일,정경환,김종호,서곤 전남대학교 촉매연구소 2001 觸媒硏究 論文集 Vol.22 No.-
Dealkylation of m-diisopropylbenzene (m-DIPB) was studied on various zeolite catalysts which have different pore structures. The very low dealkylation activity was observed on MFI zeolite because of its small pore size. The m-DIPB low conversions of MOR and FAU zeolites were due to severe deactivation of the catalysts by carbon deposites. On the other hand, the high conversion and the low deactivation in the m-DIPB dealkylation were observed on BEA zeolite with bent pores and MWW zeolite with pillow-type pores. In particular, the MWW zeolite shows a very high conversion, because the polymerization of m-DIPB resulting to carbon deposites is suppressed by sharing one m-DIPB molecule per unit pore. The high selectivity for benzene on MWW zeolite is explained by long retention time of reaction intermediate inducing consecutive dealkylation.
Chung, Kyong-Hwan,Park, Hyunwoong,Jeon, Ki-Joon,Park, Young-Kwon,Jung, Sang-Chul Elsevier 2018 CATALYSIS TODAY - Vol.307 No.-
<P><B>Abstract</B></P> <P>The photocatalytic decomposition of acetic acid-containing wastewater was assessed for the removal of pollutants and the production of hydrogen. The effects of irradiation of the liquid phase plasma were evaluated in the photocatalytic decomposition reaction. The evolution of hydrogen was also characterized by the photocatalytic decomposition of wastewater. Ni-loaded TiO<SUB>2</SUB> photocatalysts were introduced to the photocatalytic reaction. With the Ni loading to the TiO<SUB>2</SUB>, the adsorption wavelength was enlarged to the visible range. The photochemical decomposition by irradiation of the liquid phase plasma without photocatalysts produced some hydrogen evolution with the degradation of acetic acid, which was attributed to the decomposition of the reactant by active species generated by the irradiation of liquid phase plasma. The rate of hydrogen evolution from water on the photocatalyst was ca. 1.6mmol/min at 1h of process time. The photocatalytic decomposition of acetic acid was improved by the addition of Ni-loaded TiO<SUB>2</SUB> photocatalysts by the irradiation of liquid phase plasma. The Ni loading on TiO<SUB>2</SUB> brought out an enhancement of acetic acid degradation and hydrogen evolution. Hydrogen evolution was accelerated significantly due to the additional hydrogen production by the photocatalytic decomposition of acetic acid.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The photocatalytic decomposition using liquid phase plasma was assessed in acetic acid-containing wastewater. </LI> <LI> The effects of irradiation of the liquid phase plasma were evaluated over Ni-loaded TiO<SUB>2</SUB> photocatalysts. </LI> <LI> The acetic acid was degraded gradually with the progress of the photochemical reaction. </LI> <LI> The Ni loading on TiO<SUB>2</SUB> brought out an enhancement of acetic acid degradation and hydrogen evolution. </LI> <LI> Hydrogen evolution was increased in the photocatalytic reaction due to the decomposition of acetic acid. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Chung, Kyong-Hwan,Jeong, Sangmin,Kim, Byung-Joo,Kim, Jung-Sik,Park, Young-Kwon,Jung, Sang-Chul Elsevier 2018 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.43 No.11
<P><B>Abstract</B></P> <P>Hydrogen evolution by water photocatalysis using liquid phase plasma system was disserted over metal-loaded TiO<SUB>2</SUB> photocatalysts. Carbon nanotube was applied as a support for the metal-loaded TiO<SUB>2</SUB> nanocrystallites. Photocatalytic activities of the photocatalysts were estimated for hydrogen production from water. Hydrogen was produced from the photodecomposition of water by liquid phase plasma irradiation. The rate of hydrogen evolution was improved by the metal loading on the TiO<SUB>2</SUB> surface. TiO<SUB>2</SUB> nanocrystallites were incorporated above 40 wt% onto the carbon nanotube support. The carbon nanotubes could be applied as a useful photocatalytic support for the fixation of TiO<SUB>2</SUB>. Hydrogen evolution was enhanced by the Ni loading on the TiO<SUB>2</SUB> nanocrystallites supported on the carbon nanotube. Hydrogen evolution was increased apparently with addition of the alcohols which contributes as a kind of sacrificial reagent promoting the photocatalysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rate of hydrogen evolution was estimated by water photocatalysis using liquid phase plasma. </LI> <LI> Photocatalytic activity was investigated to Ni-loaded TiO<SUB>2</SUB> photocatalysts. </LI> <LI> Carbon nanotube was evaluated as a photocatalytic support for the TiO<SUB>2</SUB> nanocrystallites. </LI> <LI> The rate of hydrogen evolution was improved by metal loading on the TiO<SUB>2</SUB> surface. </LI> <LI> Hydrogen evolution was increased apparently with addition of alcohols into water. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kyong-Hwan Chung,Hyun-Soo Hwang,Ki-Young Lee 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.1
This study examined the kinetics of Salmonella typhimurium binding to an antibody using a direct assay and sandwich assay with a surface plasmon resonance (SPR) biosensor. A kinetic model was proposed based on curve-fitting of the experimental SPR sensorgrams using an integral rate equation. The SPR sensitivity in the sandwich assay was significantly higher than that in the direct assay. The association rate constants and affinities of the cell in the sandwich assay were double those in the direct assay. The enhanced binding attraction between the cell and detection antibody in the sandwich assay improved the lower limit of detection.
Esterification of oleic acid in soybean oil on zeolite catalysts with different acidity
Kyong-Hwan Chung,Byung-Geon Park 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.3
The catalytic activity of zeolites was studied in the esterification of oleic acid with methanol in soybean oil. The influences of acidity and pore structure of the zeolites were investigated in relation to conversion of the oleic acid on the zeolite catalysts. H+ ion exchanged ZSM-5 (HMFI) and mordenite (HMOR) zeolites conducted with different Si/Al ratio were employed to examine an influence of acidity in the reaction. Conversion of oleic acid was about 80% on HMOR zeolites and HMFI(25) zeolite. The conversion of oleic acid was improved as the amount of acid site increased. The amount of acid site of the zeolites affected significantly the catalytic activity in the esterification of oleic acid.
Preparation of TiO2-loaded nanocapsules and their sun protection behaviors
Kyong-Hwan Chung,Hyo-Yun Jung,Yong-Wook Lee,Ki-Young Lee 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.2
Titanium dioxide (TiO2) sol (TS) or TiO2 nanoparticles with chitosan shell were encapsulated to enhance their sun protection abilities. Nanocapsules loaded with TiO2 were evaluated for their ultraviolet (UV) absorption and UV protection rate. The effect of eicosapentaenoic acid (EPA) incorporation into the nanocapsules was examined in relation to UV absorption. The particle size of TiO2 crystallites in TS was below 30 nm, which was considerably smaller than that of a commercial TiO2 (P25 TiO2) particles. In the encapsulation of TiO2 with chitosan, the loading efficiencies of TS were higher than those of P25 TiO2. The sizes of the nanocapsules loaded with TiO2 particles ranged from 30 to 80 nm. The absorption range of irradiation wavelength was enlarged by the incorporation of EPA into the nanocapsules. The TS-loaded nanocapsules exhibited a high UV protection rate of up to 95% to both UV-A and UV-B.
Chung, Kyong-Hwan,Jeong, Sangmin,Lee, Heon,Kim, Sun-Jae,Jeon, Ki-Joon,Park, Young-Kwon,Jung, Sang-Chul Elsevier 2017 International journal of hydrogen energy Vol.42 No.38
<P><B>Abstract</B></P> <P>Photocatalytic decomposition of acetaldehyde-contained wastewater was assessed for the degradation of pollutants and the production of hydrogen. Liquid phase plasma was applied in the photoreaction as a light source. The evolution of hydrogen and acetaldehyde degradation were characterized by the photocatalytic decomposition system. Ni-loaded TiO<SUB>2</SUB> photocatalysts and various porous materials were introduced to the photocatalytic reaction. The photochemical decomposition by irradiation of the liquid phase plasma without photocatalysts produced some hydrogen evolution with the degradation of acetaldehyde, which was attributed to the decomposition of the reactant by active species generated by the irradiation of liquid phase plasma. The Ni loading on TiO<SUB>2</SUB> brought out an enhancement of acetaldehyde degradation and hydrogen evolution. In the photocatalysis of acetaldehyde-contained wastewater using the liquid phase plasma, hydrogen evolution was accelerated due to the additional hydrogen production by the photocatalytic decomposition of acetaldehyde. The porous materials could be used as an effective photocatalytic support. MCM-41 mesoporous material has acted as a highly efficient photocatalytic support to the TiO<SUB>2</SUB> photocatalyst.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The decomposition using liquid phase plasma was assessed in acetaldehyde-containing wastewater. </LI> <LI> The effects of irradiation of the liquid phase plasma were evaluated over Ni-loaded TiO<SUB>2</SUB>. </LI> <LI> The acetaldehyde was degraded gradually with the progress of the photochemical reaction. </LI> <LI> The Ni/TiO<SUB>2</SUB> brought out an enhancement of acetaldehyde degradation and hydrogen evolution. </LI> <LI> Hydrogen evolution was increased not only from the photocatalytic decomposition of acetaldehyde. </LI> </UL> </P>