• Applied Chemistry for Engineering
• /
• v.20 no.3
• /
• pp.279-284
• /
• 2009

The formation of mesoporous pores in the microporous mordenite crystals was performed by controlled silica extraction on alkaline treatment. Inner tunable mesopore size could be controlled by changing the concentration of alkaline solution. The pore structure of mordenite zeolite was studied by instrumental analysis after alkaline-treatment. To obtain the cage type mesopores, Ti-coating on the ourside mordenite crystals before alkaline treatment was investigated to be the most effective. Polymeric chiral salen Co (III) complexes were successfully encapsulated in mesoporous mordenite zeolite by "ship-in-a-bottle" method. The heterogeneous catalyst could be applied in asymmetric ring opening of epichlorohydrine by water. It showed very excellent enantioselectivity with a high yield in the catalysis.

• Journal of Adhesion and Interface
• /
• v.13 no.4
• /
• pp.151-155
• /
• 2012

In the present study, we synthesized mesoporous silica hollow spheres with different wall thickness using polystyrene (PS) spheres as a structure template, tetraethoxysilane (TEOS) as a silica source, cetyltrimethylammonium bromide (CTAB) as a template. Particle size and dispersion of PS spheres were strongly depended on the concentration of surfactant in the aqueous solutions. The size of PS spheres was increased with decreasing concentration of surfactants. Dispersion of PS particle was improved when the surfactant concentration was lower than 0.5 g of surfactant.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.965-972
• /
• 2010

The objective of this research was to evaluate for the changes of pore structures and adsorption capacities due to the increase the numbers of reactivation. The reactivated GAC had experienced three cycles of water treatment and thermal reactivation. The pore size distributions of virgin and reactivated GACs were very different. The virgin GAC was mostly microporous (< $15\;{\AA}$), with less mesopores ($20{\sim}100\;{\AA}$). The reactivated GACs was mostly mesoporous ($20{\sim}100\;{\AA}$), with less micropores (< $15\;{\AA}$). The specific surface area and total pore volume were reduced as the number of reactivation increased. The maximum adsorption capacity (X/M) of virgin GAC ($964.6\;{\mu}g/g$) for $CHCl_3$ was 2~3 times larger than 1st~3rd reactivated GAC ($255.6{\sim}399.5\;{\mu}g/g$). The maximum adsorption capacity (X/M) of virgin GAC (19.5 mg/g) for DOC (dissolved organic carbon) was equal to that of 1st~3rd reactivated GAC (18.0~18.7 mg/g).

• Journal of Adhesion and Interface
• /
• v.21 no.3
• /
• pp.113-122
• /
• 2020

Mesoporous materials are a sort of promising materials with a wide spectrum of applications due to their unique well-defined porous structures that provide high surface area and controllable pore size. Among mesoporous materials, periodic mesoporous organosilicas (PMOs) are highly emerging materials in sense of applications due to their large pore sizes and organic functionality in the frame. The organic functional groups in the frameworks of these solids allow tuning of the surface properties and modification of the bulk properties of the material. This article provides a comprehensive overview of PMOs and discusses their different functionalities, morphology and applications, such as catalysis, environmental applications, and adsorption, for which PMOs have been used after their discovery. The review article will provide fundamental understanding of PMOs and their advanced applications to readers.

• Applied Chemistry for Engineering
• /
• v.27 no.4
• /
• pp.449-454
• /
• 2016

In this study, highly monodispersed porous carbon microcapsules with a hollow core were synthesized using polystyrene (PS) beads as a hard template. The surface of PS was first modified with polyvinylpyrollidone (PVP) for the easy attachment of inorganic silica sol. After coating the surface of PVP modified PS microspheres with SBA-16 sol, the carbon microcapsules with a hollow macroporous core were fabricated through reverse replication method by filling carbon sources in the mesopores of silica mold. The hollow carbons having a mesoporous shell structure and narrow particle size distribution could be obtained after the carbonization of carbon source and the dissolution of silica mold by HF solution. The mesoporous characteristics and electrochemical properties of hollow carbon microcapsules were characterized by XRD, SEM, TEM, $N_2$ adsorption/desorption analysis and cyclic voltammetry. They showed the high electric conductivity and capability for use as efficient electro-materials such as a supercapacitor.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.263-265
• /
• 2008

자원 재활용 및 에너지 생산관점에서 폐유지로부터 환경친화적인 연료인 바이오디젤에 대한 연구가 활발히 진행되고 있다. 특히 폐유지내 함유된 유리지방산 및 수분에 의해 효율적인 에스테르화 반응이 어렵기 때문에 이를 전처리 단계에서 제거되어야 한다. 본 연구에서는 폐유지내 유리지방산을 효과적으로 제거하기 위하여 회분식 반응기에서 제올라이트 촉매의 종류에 의한 세공구조와 산성도 변화에 따른 유리지방산 전환반응에 미치는 영향을 조사해 보았다. 제올라이트 촉매의 유리지방산 전환율은 세공구조와 산성도에 따라 큰 차이를 나타내었다. 유리지방산 전환율은 FAU < MOR < MFI < BEA의 순으로 높았다. 제올라이트의 세공구조는 1차원적인 구조를 가질 경우 탄소침적이 일어나지만 3차원적인 세공구조를 가지는 경우 탄소침적에 의한 촉매의 활성저하가 감소된다. 또한 제올라이트의 산성도에 따른 특성으로는 유리지방산의 전환반응에는 중간정도의 산세기를 가진 촉매가 유리함을 확인하였다. 그러므로 폐유지로부터 유리지방산을 제거하기 위한 우수한 제올라이트 촉매로는 BEA 제올라이트 촉매임을 확인하였다.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.4
• /
• pp.384-388
• /
• 2006

The adsorption ability of polar and toxic substance was greatly enhanced by treating activated carbon with acid solution and impregnating iron, copper, or silver by using in 0.1 M $FeSO_4{\cdot}7H_2O,\;CuSO_4{\cdot}5H_2O,\;AgNO_3$ 300 mL per activated carbon 50 g. Physical and chemical properties of the metal impregnated activated carbons were measured using specific surface area, pore volume and size distribution, scanning eletron microscope(SEM), adsorption isotherm. When activated carbon was treated with acid, the quantity of impregnated metal increased about 1.3 times since the micropores were converted to mesopores or macropores. Both the physical absorption by micropores and chemical absorption by metal ions could be achieved simultaneously with the metal impregnated activated carbon because the capacity of micro pores did not change even after metal ions were impregnated.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.8
• /
• pp.807-812
• /
• 2005

This study is to investigate the correlation of pore structures of Zeolite 5As modified with acid and their adsorption capacity of toluene vapor using the dynamic adsorption method. The experimental results showed that the modification with acid allowed more micropores and enlarged the existing pores. Toluene vapor was mainly adsorbed on the surface of pores over $15\;{\AA}$ in diameter. The equilibrium adsorption capacity of toluene vapor of the modified Zeolite 5As was in the range of $15{\sim}70\;mg/g$ and the equilibrium adsorption capacity was increased to f times than that of the Zeolite 5A. The correlation between the total cumulative surface area and the equilibrium adsorption capacity was hard to say linear. The correlation in diameter between the cumulative surface area in the range of over $15\;{\AA}$ and the equilibrium adsorption capacity gate the highest correlation factor of 0.997.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.12
• /
• pp.2141-2148
• /
• 2000

This study is to investigate changes of pore structure with different burn-off degree of steam activated carbons manufactured from domestic anthracite. The activated carbons were characterized by adsorption of nitrogen at 77 K. Steam activation substantially enhanced the porosity of the activated carbons. Burn-off increased linearly according to increasing activation time, and total pore volume and BET surface area increased with burn-off. Activation at $800^{\circ}C$ increased more micropore volume than that at $950^{\circ}C$. Activated carbons manufactured at high temperature had less microporosity than that at lower temperature, but had more developed macroporosity. The steam activation produced an enlargement of pore below $100{\AA}$ diameter in the activated carbons. Furthermore, the porosity in the $6{\sim}40{\AA}$ pore diameters range increased considerably with the degree of burn-off.

• Polymer(Korea)
• /
• v.37 no.5
• /
• pp.592-599
• /
• 2013

In this study, polyacrylonitrile (PAN)-based porous carbon nanofibers were prepared from PAN polymer solution by electrospinning and KOH activation with various concentrations, and the characterization of pore structures and carbon dioxide adsorption was investigated. Manufactured PAN-based activated carbon nanofibers tend to decrease diameter and increase surface oxygen functional groups depending on the increasing concentration of KOH solution. In addition, according to the results of nitrogen adsorption for pore properties analysis, it indicated increase of the specific surface area in conformity with increasing concentration of KOH solution. Micropore volume of treated activated carbon nanofibers (ANCF) by 4 M KOH was the largest compared with other samples and mesopore volume of treated ANCF by 8 M KOH was the largest volume, respectively. The concentration of KOH effects textural and surface properties, as represented by BET and XPS, which enhance carbon dioxide adsorption capacity at 0 and $25^{\circ}C$.