Fabrication of Poly(γ-glutamic acid) Monolith by Thermally Induced Phase Separation and Its Application

( Sung Bin Park ),( Takashi Fujimoto ),( Eiichi Mizohata ),( Tsuyoshi Inoue ),( Moon Hee Sung ),( Hiroshi Uyama ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.7

Monoliths are functional porous materials with a three-dimensional continuous interconnected pore structure in a single piece. A monolith with uniform shape based on poly(γ-glutamic acid) (PGA) has been prepared via a thermally induced phase separation technique using a mixture of dimethyl sulfoxide, water, and ethanol as solvent. The morphology of the obtained monolith was observed by scanning electron microscopy and the surface area of the monolith was evaluated by the Brunauer Emmett Teller method. The effects of fabrication parameters such as the concentration and molecular mass of PGA and the solvent composition have been systematically investigated. The PGA monolith was cross-linked with hexamethylene diisocyanate to produce the water-insoluble monolith. The addition of sodium chloride to the phase separation solvent affected the properties of the cross-linked monolith. The swelling ratio of the cross-linked monolith toward aqueous solutions depended on the buffer pH as well as the monolith fabrication condition. Copper(II) ion was efficiently adsorbed on the cross-linked PGA monolith, and the obtained copper-immobilized monolith showed strong antibacterial activity for Escherichia coli. By combination of the characteristic properties of PGA (e.g., high biocompatibility and biodegradability) and the unique features of monoliths (e.g., through-pore structure, large surface area, and high porosity with small pore size), the PGA monolith possesses large potentials for various industrial applications in the biomedical, environmental, analytical, and separation fields.

Ground, sieved, and C18 modified monolithic silica particles for packing material of microcolumn high-performance liquid chromatography

Ko, J.H.,Baik, Y.S.,Park, S.T.,Cheong, W.J. Elsevier 2007 Journal of chromatography Vol.1144 No.2

We here report a new type of stationary phase for microcolumns. C18 modified silica monolith particles were prepared by grinding and sieving the silica monolith followed by C18 modification and end-capping, and were used as packing material. Ground silica monolith particles were not spherical but irregular with some residual monolithic network structure. The separation efficiency of the stationary phase made of sieved monolith particles (5-10μm) was better than that of the stationary phase made of unsieved particles. The microcolumn packed with the sieved C18 ground monolith particles (5-10μm) showed quite good separation efficiency (height equivalent to theoretical plate, HETP, as low as 15μm) and it was even superior to the microcolumn packed with a commercial spherical 5μm C18 stationary phase. The column pressure drop of C18 monolith particles was about two-third of that of the commercial spherical C18 phase. The preparation method of C18 stationary phase with ground and sieved silica monolith particles presumably suggests advantages of simplicity and convenience in modification and washing procedures compared to bulk silica monolith. It also showed both improved separation efficiency and low back pressure.

가솔린 엔진의 배출가스 저감을 위한 듀얼 모노리스형 촉매변환기의 형상 및 귀금속 촉매의 축방향 분포 최적화

김영득(Young-Deuk Kim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

In practical applications, monolithic catalytic converters are operated at non-isothermal conditions. In this case, the active metal distribution along the length of the converter may influence its performance. Indeed, better conversions can be achieved by controlling the distribution of the same quantity of active material. In this study, a one-dimensional catalyst model has been adopted to predict the transient thermal and conversion characteristics of a dual monolithic catalytic converter with Platinum/Rhodium (Pt/Rh) catalysts. The optimal design of a longitudinal noble metal distribution of a fixed amount of catalyst is investigated to obtain the best performance of a dual monolithic catalytic converter by using a micro genetic algorithm with consideration of heat transfer, mass transfer, and chemical reaction in the monolith during FTP-75 cycle. The optimal axial distribution of the catalyst is determined by solving the multi-objective optimization problems which are to minimize both the CO cumulative emissions during FTP-75 cycle, and the difference between the integral value of a catalyst distribution function over the monolith volume and total catalytic surface area over total monolith volume. The parametric investigations for three cell densities of the front monolith are carried out by varying the volume ratio between front and rear monoliths with fixed volume and cell density of the rear monolith.

콘크리트 건축물의 모놀리스적 표현특성에 관한 연구

원경섭(Kyoung-Sop Won) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.12

오늘날 다변화된사회에서 어떤 스타일의건물이 동시대를 대표하는 건축적 양식인지알기어렵다. 그 중에서 모놀리스적 스타일의 건물에서 드러나는 단순함은 현대의 지극히 복잡한 사회구조와 대칭점을 이루며 그 가치를 인정받을 수 있다. 본 논문에서는 21세기 초반 단열경량골재콘크리트가 사용된 건물의 분석을 통해서 모놀리스적 표현에 대한 개념정의와 그 특징들이 공간 및 형태 그리고 건축구법에서 어떻게 표현되고 있는지에 대해 연구하였다. 여러 재료가 층을 이루어 구성되는 다층적 방식의 외벽시스템과는 달리, 단열경량골재콘크리트에 의한 외벽은 단일재료로서 콘크리트를 사용하여 거푸집을 빈틈없이 채워서 만들어진 덩어리 형태이며 그 자체로 모놀리스적이다. 이러한 점은 동일한 재료에 의한 내외부공간의 동질성, 고형(固形)으로서 표면의 연속성, 스테레오토믹적(stereotomic) 구축방식의 공간적 특성, 노출콘크리트사용에 의한 물질성의 표현, 덩어리와 공간 사이의 대비적 특성을 가진 공간을 만들어 낸다. 그리고 현대건축의 다층적 외벽 방식의 모놀리스적 건축에 대한 담론을 외부로 드러나는 형상적 특징과 더불어 구조와 재료, 그리고 그것이 공간에 끼치는 영향에 까지 논의의 범위를 넓힐 수 있는 기회를 제공한다. In today"s diversified society, it is hard to know which building style represents the architectural style of the time. The simplicity found in monolithic-style buildings forms a symmetrical point with fairly complex structure, and its value can be acknowledged. This study analyzes buildings made of insulating lightweight aggregate concrete in the early 21st century, defines the concept of monolithic expression, and examines how these characteristics are expressed in the space, forms, and structural methods in construction. Unlike a multi-layered exterior wall system, which features multiple layers composed of a variety of materials, the exterior walls built with insulating lightweight aggregate concrete comes in a lump form with a mold form that is tightly filled with concrete as a single material and is monolithic. This is attributed to the creation of spaces characterized by the homogeneity of inner and outer spaces with the use of the same material, continuity of the surface as solidity, spatial characteristics of the stereotomic construction, expression of materiality with the use of exposed concrete, and the contrast of the lump and the space. This not only reveals formal characteristics that expose a discourse about monolithic architecture in contemporary architecture but also provide an opportunity to extend the range of discussion to structures and materials and even to their effects on space.

Proline-based polymeric monoliths: Synthesis, characterization, and applications as organocatalysts in aldol reaction

Garg, Dipti,Ahn, J.-H.,Chauhan, Ghanshyam S. Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of polymer science Part A, Polymer chemist Vol.48 No.5

<P>Proline-based polymer monoliths were synthesized via green protocol using lipase-catalyzed esterification of methacrylic acid and 4-hydroxyproline. Prolinyl methacrylate thus prepared was polymerized in situ as crosslinked monolith. The monolith was characterized by various techniques such as Fourier transform infrared, <SUP>1</SUP>H-NMR, <SUP>13</SUP>C-NMR, scanning electron microscopy (SEM), X-ray diffraction (XRD), and nitrogen analysis and used as catalyst in aldol reactions. The swelling behavior of the monolith was also studied as function of various external parameters like pH and temperature. The monoliths synthesized with 1% crosslinker was selected as candidate monolith for use as catalyst in aldol reaction, which was studied as a function of time, temperature, substrate structure, and amount of water:EtOH. The catalysts exhibited high efficiency in the cross aldol reaction, especially with the aromatic substrates having electron withdrawing substituent, and also good activity retention was observed when recycleability was studied up to five cycles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1007–1015, 2010</P> <B>Graphic Abstract</B> <P>Proline-based polymer monoliths were synthesized via green protocol using lipase-catalyzed esterification of methacrylic acid and 4-hydroxyproline. The monomer was polymerized to polymer monoliths, and the latter were used as heterogeneous polymer catalysts in the aldol reaction that was studied in three forms viz. simple aldol, cross aldol, and ketone-aldehyde reaction. The catalysts exhibited high efficiency in the cross aldol reaction, especially with the aromatic substrates having electron withdrawing substituent, and reasonable retention of catalytic efficiency up to five cycles. <img src='wiley_img/0887624X-2010-48-5-POLA23845-gra001.gif' alt='wiley_img/0887624X-2010-48-5-POLA23845-gra001'> </P>

An Evaluation of Performance of Numerical models for the Flow Characteristics of Automotive Aftertreatment Device

정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim),강우(Woo Kang),이제형(Je-Hyung Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Computational Fluid Dynamics(CFD) has been widely used in the automotive industry to simulate the flow within the converter. Most of CFD models for predicting flow through converter assume a monolith resistance based on one-dimensional laminar flow and treat a monolith as porous medium. However, auto-catalyst is getting closer to engine to have fast warm-up and wide-angled diffusers are often employed to connect the upstream exhaust pipe to the monolith. Therefore, the question arises as to the accuracy of porous medium approach based on one-dimensional laminar flow and model validation studies are essential if it is to become a useful design tool. From these reasons, this paper evaluates the prediction performance of porous medium and three-dimensional multichannel model by comparing with experimental results for understanding the limitation of porous medium approach and suggesting guidelines for the development of more accurate flow model. For evaluating each models, this work calculates the flow mal distribution and pressure drop across the monolith of an axisymmetric catalyst assembly under steady state condition. The results shows that porous medium model under-predicts flow maldistributions in the monolith by 6.4% at maximum and three-dimensional multi-channel model also under-predicts by 10.3% at maximum. From the results of this work, it can be concluded that modification of porous medium approach is strongly required to account of additional entrance effect and detailed modeling of monolith channels can not be alternative for more accurate flow simulation of auto-catalyst due to the inaccuracy Averaged Navier Stokes k-ε type turbulence model under abrupt change of length scale condition.

제철소 적용을 위한 저온형 금속지지체 탈질 코팅촉매 최적화 연구

이철호(Chul-Ho Lee),최재형(Jae Hyung Choi),김명수(Myeong Soo Kim),서병한(Byeong Han Seo),강철희(Cheul Hui Kang),임동하(Dong-Ha Lim) 한국청정기술학회 2021 청정기술 Vol.27 No.4

Estimation for warfarin in pharmaceutical preparation using monolithic column

Zahraa Hadi Shareef,Ahmed Ali Alkarimi 한국분석과학회 2024 분석과학 Vol.37 No.4

This study aims to developing a method for estimating pharmaceutical compounds within a monolith column using high-performance liquid chromatography (HPLC). The monolithic column was prepared using copolymerization of glycidyl methacrylate, co-ethylene dimethacrylate, and co-acrylic acid inside a borosilicate tube of specific dimensions a 60 mm borosilicate tube length with 1.5 mm and 3.5 mm inner and outer diameters, respectively. A UV Ultra violet source with a wavelength of 365 nm was used, and the polymerization process involved mixing glycidyl methacrylate, acrylic acid, ethylene dimethacrylate as a binder, and 2,2-dimethoxy2-phenyl acetate phenone as an initiator in suitable solvents consisting of ethanol and 1-hexanol. The polymerization process formed the monolith column after 4 minutes, and subsequently, the epoxy groups were altered to diol groups using 0.2 M hydrochloric acid HCl, which were pumped through the column for 3 hours at a flow rate of 10 µL·min−1 . Various techniques, such as Scanning Electron Microscope SEM, Brunauer-Emmett-Teller BET, Fourier-transform infrared spectroscopy FT-IR and HNMR, were utilized to characterize and confirm the structure of the monolith. The prepared monolith was employed to estimate and identify the pharmaceutical compound of warfarin using high-performance liquid chromatography HPLC. The analytical curve of warfarin was linear in the range of 3 to 100 µg·mL−1 with an r2 value of 0.999. The detection and quantification limits were 0.932 and 2.788 µg·mL−1 , respectively. The molar absorptivity and Sandells sensitivity were 2.99138 × 106 L·mol−1 ·cm−1 and 103. 1 × 10−3 µg·cm−2 , respectively

A new route to the stable capture and final immobilization of radioactive cesium

Yang, Jae Hwan,Han, Ahreum,Yoon, Joo Young,Park, Hwan-Seo,Cho, Yung-Zun Elsevier 2017 Journal of hazardous materials Vol.339 No.-

<P><B>Abstract</B></P> <P>Radioactive Cs released from damaged fuel materials in the event of nuclear accidents must be controlled to prevent the spreading of hazardous Cs into the environment. This study describes a simple and novel process to safely manage Cs gas by capturing it within ceramic filters and converting it into monolithic waste forms. The results of Cs trapping tests showed that CsAlSiO<SUB>4</SUB> was a reaction product of gas-solid reactions between Cs gas and our ceramic filters. Monolithic waste forms were readily prepared from the Cs-trapping filters by the addition of a glass frit followed by thermal treatment at 1000°C for 3h. Major findings revealed that the Cs-trapping filters could be added up to 50wt% to form durable monoliths. In 30–50wt% of waste fraction, CsAlSiO<SUB>4</SUB> was completely converted to pollucite (CsAlSi<SUB>2</SUB>O<SUB>6</SUB>), which is a potential phase for radioactive Cs due to its excellent thermal and chemical stability. A static leaching test for 28 d confirmed the excellent chemical resistance of the pollucite structure, with a Cs leaching rate as low as 7.21×10<SUP>−5</SUP> gm<SUP>−2</SUP>/d. This simple scheme of waste processing promises a new route for radioactive Cs immobilization by synthesizing pollucite-based monoliths.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cs gas was chemically adsorbed to the SA filter to form thermally stable CsAlSiO<SUB>4</SUB>. </LI> <LI> Monoliths were readily made from the Cs-SA filters by a simple thermal process. </LI> <LI> CsAlSiO<SUB>4</SUB> was effectively converted to pollucite during the synthesis of monoliths. </LI> <LI> The chemical resistance of pollucite was high, comparable to data of other studies. </LI> </UL> </P>

급가감속 운전에 따른 듀얼 모노리스형 촉매변환기 내의 유동 균일도와 압력 강하에 관한 연구

김영득(Young-Deuk Kim),정수진(Soo-Jin Jeong),김우승(Woo-Seung Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Conversion efficiency, durability and pressure drop of automotive exhaust catalysts are dependent on the flow distribution within the substrate. Conventional porous medium approach assuming monolith resistance based on one-dimensional laminar flow for simulating the flow through automotive exhaust catalysts overpredicts the flow uniformity in the monolith. In this study, additional pressure loss accounting for entrance effects due to oblique flow incident on the front face of monolith as a consequence of flow separation and recirculation within the diffuser is considered and incorporation of an additional pressure loss improves the predictions for the maximum flow velocity within the substrate. A numerical study of three-dimensional unsteady incompressible non-reacting flow inside various dual-monolith catalytic converters for the rapid acceleration/deceleration driving has also been conducted.