• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.198-199
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• 2009

킬레이팅 고분자를 메조기공 탄소 표면 위에 흡착시킴으로써 금속이온과 착물을 형성할 수 있는 기능성 나노구조체를 제조하였다. 악티늄족 원소를 단일입자 내에 영구처분을 위한 예비연구로서 Eu을 대용물(surrogate)로 사용하여 기능성 나노 구조체에 주입한 후 메조기공 입구를 고분자반응을 통해 봉쇄함으로써 Eu의 단일입자 내 고정화를 시도하였다. 시간에 따라 침출현상을 분석한 결과, 고분자로 메조기공을 blocking 하였을 때 Eu의 침출현상이 크게 완화되는 것을 확인하였다. 이는 시멘트화나 유리화 등과 같은 고비용 공정을 거치지 않고도 단일입자 내 유해 금속의 영구처분이 가능하다는 것을 의미한다. 더 나아가, 이러한 접근방법은 지지체로 메조기공 탄소에 국한되지 않고 실리카와 같은 다른 메조기공 금속산화물에 적용될 수 있다는 점에서 큰 강점이 있다.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.880-885
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• 2008

Spray pyrolysis was applied to prepare spherical silica particles with mesopores of a regular structure. The physical properties such as surface area, pore size, pore structure, particle size, and morphology were studied by BET, SEM, SAXS, and DLS analysis. At a fixed gas flow rate, the BET surface area changed from 200 to $1,290m^2/g$ as changing the CTAB/TEOS molar ratio from 0.05 to 0.3. At a fixed CTAB/TEOS ratio, the surface area of silica particles was varied from 1,062 to $1,305m^2/g$ with changing the gas flow rate from 10 to 40 l/min. The average pore size measured by BJH desorption was about $21{\sim}23{\AA}$ and not significantly influenced by the CTAB/TEOS ratio and the gas flow rate. Finally, the highest surface area which was $1,305m^2/g$ were obtained when the CTAB/TEOS ratio and the gas flow rate were 0.2 and 20 l/min, respectively. According to SAXS analysis, the prepared silica particles showed a strong peak at $2{\theta}=2.6^{\circ}$ and two minor peaks around $2{\theta}=4.4^{\circ}$ and $5.1^{\circ}$, which are due to regular mesopores of hexagonal structure. The morphology of silica particles prepared were spherical shape and the average particle size was $1.0{\mu}m$.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.190-194
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• 2016

Tricyclopentadiene (TCPD) is one of the important precursors for making tetrahydrotricyclopentadiene, which is well known as a next-generation fuel with high energy density. In this study, TCPD was obtained by polymerization reaction of dicyclopentadiene (DCPD) using an ionic liquid (IL) supported mesoporous silica catalysts. ILs were supported to two kinds of mesoporous silica catalysts with different pore sizes such as MCM-41 and SBA-15. Four different ILs were supported to mesoporous silicas using anionic precursors such as CuCl or $FeCl_3$ and cationic precursors such as triethylamine hydrochloride or 1-butyl-3-methylimidazolium chloride. We proved that IL supported mesoporous silicas showed better catalytic performance than those of using non-supported prestine IL in the aspect of TCPD yield and DCPD conversion. Among four kinds of IL supported mesoporous silica catalysts, CuCl-based IL supported MCM-41 system showed the highest TCPD yield.

• KSBB Journal
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• v.28 no.3
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• pp.208-212
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• 2013

Four types of mesoporous spherical silica adsorbents with different physical properties were prepared by spray pyrolysis and were used for the purification of the anticancer agent paclitaxel from plant cell cultures. Pore size had a greater effect on the removal of plant-derived impurities during the pre-purification of paclitaxel compared with surface area and pore volume. An appropriate pore diameter (~9.07 nm) was required to achieve the highest purity (~46.1%) and yield (~82.3%) of paclitaxel. These results were confirmed by HPLC analysis of the absorbent after treatment and Thermogravimetric analysis of the organic substances bonded to the adsorbent.

• Clean Technology
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• v.19 no.3
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• pp.342-346
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• 2013

Several types of mesoporous silica-alumina adsorbents with varied $SiO_2/Al_2O_3$ ratios were prepared by spray pyrolysis and were used for the purification of the anticancer agent paclitaxel. When $S_{0.5}A_{0.5}$ (Silica/Alumina molar ratio = 0.5/0.5) was used, the highest purity (~27%) and yield (~63%) of paclitaxel were obtained from adsorbent treatment and hexane precipitation. Removal of impurities was confirmed by TGA analysis of the organic substances that were adsorbed to the adsorbent.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.139-147
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• 2007

For environmental remediation of a contaminated groundwater plume, the use of zero-valent metal represents one of the latest innovative technologies. In this study, the effects of denitrification by zero-valent iron adsorbed in mesoporous silicas have been studied for groundwater contaminant degradation. The mesoporous silica was functionalized with 3-mercaptopropyltrimethoxysilane (MPTS) ligands and the zero-valent iron precipitated in the mesopore of granular silica was made by $FeCl_2$ and $NaBH_4$. Hydrogen was exchanged with $Fe^{2+}$ ions in the granular silicas. And then the ions were reduced by sodium borohydride in the mesoporous silicas. The surface area of the silica determined via the BET method ranged from 858 to $1275m^2/g$. The reductive reaction of nitrate-nitrogen indicated that the degradation of nitrate-nitrogen appeared to be pseudo first-order with the observed reaction rate constant kobs ($0.1619h^{-1}$) and to be directly proportional to the specific surface area. Therefore, the mesoporous silica with nano zero-valent iron proposed as a novel treatment strategy for contaminated groundwater was successfully implemented herein for the removal of nitrate-nitrogen.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.383-389
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• 2020

Mesoporous silica solid catalysts modified with sulfonic acid were prepared for cationic ring-opening polymerization of octamethylcyclotetrasiloxane (D₄). Two sets of MCM-41 (1.7 and 2.8 nm) and SBA-15 (8.1 and 15.9 nm) with different pore sizes were used as catalyst supports. The surface of silica materials was modified with (3-mercaptopropyl)trimethoxysilane by silylation reaction and oxidized to sulfonic acid. The structures of the prepared catalysts were examined by X-ray diffraction and nitrogen adsorption-desorption. The pore size, specific surface area, and pore volume of the modified solid catalysts decreased slightly. In addition, the modification of the sulfonic acid on the silica surface was confirmed by using infrared spectroscopy and nuclear magnetic resonance spectroscopy. To observe the effect of the particle size on the catalytic activity, it was observed with a scanning electron microscope. The catalysts were used to synthesize PDMS through a ring-opening polymerization of D₄, and the conversion and polymerization rate of the polymerization reaction depended on the pore size, specific surface area, particle size, and particle agglomeration of the catalysts. In order for the polymerization rate, the catalyst prepared with SBA-15 of 8.1 nm pore size had the fastest reaction rate and showed the best catalytic activity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.3 s.47
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• pp.321-328
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• 2004

Nano silica ball and nano carbon ball are developed commercially by template synthesis method. Adsorption of unpleasant smelling substances such as ammonia, trimethylamine, acetaldehyde and methyl mercaptane onto nano carbon ball with hollow macroporous core/mesoporous shell structures, nano carbon ball, was investigated and compared with that onto odor adsorbent materials, activated carbon, commercially available. The adsorption and decomposition of malodor at nano carbon ball exhibited superior than those onto activated carbon. The physicochemical properties such as mesopore size distributions, large nitrogen BET specific surface area and large pore volume and decomposition of malodor were studied to interpret the predominant adsorption performance. The nano carbon ball is expected to be useful in many applications such as deodorizers, adsorbent of pollutants.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.223-228
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• 2006

Pore-size controlled porous carbons for the catalyst supports of the direct methanol fuel cell were prepared from the mesophase pitch by using the silica spheres with different sizes. Pitch solution in THF and spheres were mixed, carbonized and etched by 5 M NaOH to make porous carbon. Specific surface area of the porous carbons was $14.7{\sim}87.7m^2/g$ and average pore diameter was 50~550 nm which were dependent on the size of silica spheres. Aqueous reduction method was used to load 60 wt% PtRu on the prepared porous carbon supports. The electro-oxidation activity of the supported 60 wt% Pt-Ru catalysts was measured by cyclic voltammetry and unit cell test. For the 60 wt% Pt-Ru/porous carbon synthesized by 50 nm silica, current density value in the cyclic voltammetry test was $123mA/cm^2$ at 0.4 V and peak power density in the unit cell test were 105 and $162mW/cm^2$ under oxygen at 60 and $80^{\circ}C$, respectively.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.269-275
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• 2021

In this study, ordered mesoporous silica-supported Ni catalysts were prepared for catalytic partial oxidation of methane (CPOM) by using electroless nickel plating method. Unlike conventionally impregnated catalysts, the electrolessly-plated nickel catalyst showed that nickel was highly dispersed and formed stably on silica-supported surface. It was verified by TEM-EDS analysis. During the activity tests, the electrolessly-plated nickel was barely sintered and the amount of carbon deposition was very small. Consequently, the catalyst was far less deactivated, while the sintering was significantly observed in the cases of the catalysts prepared by the conventional impregnation method. Regarding the palladium-promoted catalysts, the reducibility of nickel was increased, and the reaction performances were enhanced in terms of CH4 conversion and H2/CO ratio of produced syngas.