배가스의 이산화탄소 농도인 14%를 기준으로 실험실규모에서 벤치스케일로 격상하였고, 랩스케일에서는 모사가스로 진행한 반면 벤치스케일에서는 실제 보일러에서 나오는 배가스로 실험을 진행하였다. 배가스의 높지않은 압력조건을 감안하여 본 연구에서는 1단 분리막 공정실험에서는 주입부 압력 2 bar, 투과부압력 0.2 bar에서 실험을 진행 하였고, 2단 막 공정에서는 1단 분리막은 동일하게, 2단 분리막 주입부 압력 1 bar, 투과부 압력 0.05 bar에서 진행하였다. 결론적으로 랩스케일에서 벤치스케일로 격상했을 경우 같은 경향성을 볼 수 없었으며 이는 실제 발전소 및 보일러에서 연소되는 배가스를 분리막공정으로 포집하는 것은 사전연구가 더욱 필요하다는 것을 확인하였다.
본 연구에서는 PAN과 폴리설폰의 두 지지체와 PEBAX 1657, 2533 두 선택층을 형성하였고, 지지체의 투과저항으로 인한 복합 막의 기체 투과도와 선택도의 차이를 확인하였다. 투과선택도를 향상시키기 위하여 PEG를 첨가하여 20에서 50 wt% 범위에서 농도를 달리하여 막을 제조한 후 CO2, N2 기체 투과성능을 측정하였다. 투과 성능이 가장 우수한 복합막의 물성 평가로써, PEBAX 복합평막의 미세구조를 관찰하였고, PEG 함량의 증가로 인한 Polyether 유리전이온도의 변화를 확인하였다. PEG 첨가제에 의한 PEBAX 복합평막은 에틸렌옥사이드 그룹으로 이루어진 PEG가 이산화탄소에 친화성을 가지고 있어서, PEG가 증가함에 따라 이산화탄소의 투과도를 향상시킬 수 있었다.
고분자는 많은 수의 원자로 구성 되어 있기 때문에, 분자동역학 연구 시 다양한 변수를 고려 해야 하는 어려운 연구 대상이다. 구성 원자 개수가 너무 많은 경우 계산 시간이 오래 걸리는 문제점이 있으며, 반대로 원자의 개수를 너무 줄일 경우에는 실제 모사 대상을 정확하게 반영하지 못할 수가 있다. 특히, 기체 분리와 같은 분야에서는 기체 분자가 고분자 내에서 투과하는 것을 반영한 계산이 필요하기 때문에 오랜 시간동안 계산을 하게 되며, 이로 인하여 모델의 크기를 정하는데 있어서 앞서 언급한 모든 요소를 적절히 고려하는 것이 필요하다. 본 연구에서는 분자동역학 전산모사에 있어서 고분자를 구성하는 원자의 개수와 그에 따른 영향을 연구하기 위하여, 고분자 주쇄 길이를 조절하면서 고분자 모델의 특성을 분석하였다.
SIFSIX-3, containing a coordinative complex of hexafluorosilicate, transition metal ions, and the organic ligands, is a subclass of metal-organic frameworks (MOFs). SIFSIX-3 is considered a high capacity adsorbent for CO2 capture due to the enriched interaction sites of fluoride groups in SIFSIX. Also, SIFSIX-3-Zn is known to have an appropriate effective aperture size for efficient CO2/CH4 separation. In this work, we successfully incorporated different metal-based SIFSIX-3 crystallites into polyimide (PI) matrix and demonstrated that the associated mixed matrix membranes improved CO2/N2, CO2/CH4 and CO2/CO separation performance compared to pristine polyimide membranes due to the excellent molecular sieving behaviors of SIFSIX crystallites.
압력-분배 탈기방식으로 막접촉기를 구성하여 바이오가스 정제를 하였다. 폴리프로필렌(PP) 중공사막 모듈과 물리흡수제를 이용하여 막접촉기 성능 평가를 수행하였다. 실험은 흡수 압력, 가스의 유량, 흡수 온도 및 흡수제의 농도등 다양한 조건에서 수행하였다. 특히 CO2 흡수능이 높은 상용 흡수제인 프로필렌카보네이트(PC)와 물의 혼합흡수제를 사용하여 회수성능이 향상되었다. 탈기 방법이 개선된 압력-분배 탈기방식의 막접촉기는 50% CO2/50% CH4의 바이오가스 모사가스로부터 바이오메탄을 98% CH4 순도와 91%의 회수율로 정제하였다. 따라서 압력-분배 막접촉기를 통해 바이오가스로부터 수송용 바이오메탄의 생산이 가능함을 확인하였다.
Membranes techniques used to convert chemical energy into electrical energy from energy sources such as hydrogen, salt water, and water. Membrane materials have transport property of desire molecular and barrier property for satisfy to requirement of cell performance. Typically, PFSA polymer is used to fabricate membrane. Each material has different characteristics depending on the membrane formation conditions. Macroscopic characteristics are difficult to correlation with molecular motion, mobility, and transport within membrane matrices. NMR spectroscopy can analysis about these characteristics by observing the molecule level. In this study, NMR spectroscopy can provide fundamental information of PFSA ionomers and correlation with macroscopic characteristics.
Commercial polystyrene-based ion exchange membranes have simple manufacturing processes, they also possess the poor durability due to their brittleness. Poly(ethylene glycol)methyl ether methacrylate with hydrophilic side chain of poly(ethylene glycol) (PEG) was used as a co-monomer to make the membranes have improved flexibility. Hydrophilicity of the anion exchange membrane was able to be adjusted by varying the chain lengths of the PEG polymers. For the preparation of the anion exchange membranes, a porous PE substrate was immersed into monomer solutions and thermally polymerized and crosslinked. The prepared membranes were then subsequently post-aminated using trimethylamine (TMA). The prepared pore-filled anion exchange membranes were evaluated in terms of ion exchange capacity (IEC), electric resistance (ER) and water uptake.
In this study, we prepared thin composite membranes in which a support layer and a selective layer are covalently bonded in a simple method. The graft polymerization was carried out using UV/Ozone on a commercial Poly(sulfone) (PSf) ultrafiltration membrane with Poly((ethylene glycol) methyl ether methacrylate) (PEGMA) possessing CO2affinity. As a result, nano-pores on the surface membrane were covered with PEGMA. The covalent bonding of the composite membranes has the advantage of improving stability. In addition, due to the thin selective layer formed by the graft polymerization, highly gas permeation characteristics are exhibited, and efficient process performance can be expected. The final composite membranes were investigated in terms of their chemical structures and elements, morphology, and gas permeation properties.
Polymer electrolyte membrane fuel cells (PEMFCs) have attracted particular interest as alternative and enviromentally friendly energy source for both mobile and stationary application. The perfluorosulfonic acid membranes, such as Nafion® are most used PEMs because of their good chemical and electrochemical stability. However they have drawbacks such as high cost, low application temperature, insufficient durability. Sulfonated poly (arylene ether)s, poly (phenylene ether)s, poly (arylene ether ketone)s have beem developed. This work is an attempt to synthesize sulfonated poly (arylene ether)s contained phosphinate moiety which is pendant phenyl structure. Sulfonated poly (arylene ether)s membranes were prepared from DOPO-BPA, 4,4’-sulfonyl diphenol(SFDPS), 1,4-bis(4-fluoro benzoyl)benzene(1,4-FBB).
In pressure retarded osmosis (PRO) process, thin film composite (TFC) type membranes which can withstand high operating pressure are required. In this study, glass fibers (GF) are used as additive for mechanical strength enhancement of the support layer of TFC membranes. The support layers were fabricated by a phase inversion method by using the casting solution of blended GF (two different size of milled GF) with polyethersulfone (PES). The fabricated support layers were characterized by FE-SEM, FT-IR, contact angle goniometer, and universal testing machine. Lab-scale ultrafiltration experiment was carried out to measure their performance. As a result, the support layer with milled GF showed higher mechanical strength and water flux than the pure PES support layer, and the support layer with smaller size GF showed higher performance.
물 부족 현상의 해결책으로 저에너지 해수담수화가 가능한 정삼투 공정에 대한 연구가 활발히 진행되고 있다. 정삼투 공정은 가압 조건이 필요하지 않으므로 에너지 비용을 저감할 수 있다는 장점이 있다. 이에 사용되는 유도 용질은 높은 삼투압을 나타내어 높은 수투과를 발생시키고, 염의 역확산은 낮아야한다. 또한 유도용액 후처리 공정에서 저렴한 비용으로 쉬운분리가 가능해야한다. 최근에는 고분자 전해질을 이용한 유도용질, 온도감응성 고분자를 이용한 유도용질, 나노재료를 이용한 나노파티클 유도용질의 연구가 진행되었으나 상용화에는 이르지 못하고 있다. 본 연구에서는 높은 수투과량, 낮은 염의 역확산을 나타내고 나노여과로 쉽게 회수 가능한 카복시화된 폴리에틸렌이민 유도용질을 합성하고 정삼투 공정에서의 성능평가 및 다른 유도용액과 비교실험을 수행하였다.
As ZIF materials have their unique properties such as high surface area, tunable pore structure, thermal and chemical stability, they can be used in gas separation. In this work, we synthesized ZIF-8 seed layer by combining ZnO coating on the support and the conversion synthesis of ZnO layer in H-mIm solution to ZIF-8 layer, followed by the secondary growth synthesis for ZIF-8 membranes. The effect of solvent on conversion seeding had been investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate. The optimum solvent combination (water and methanol) was studied according to the thickness of the ZnO layer used in the conversion seeding. The obtained membranes showed excellent performance for propylene/propane gas separation. The thicker the ZnO layer, the lower the permeability.
We fabricated dual-phase free-standing polymeric membrane for high performance CO2/N2 separation, introducing amphiphilic, CO2-philic copolymer via one-step free radical polymerization, or (2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate)-graft-poly(oxyethylene methacrylate) (PBE). PBE filler partially interacts with Pebax polymer matrix to generate the interconnected CO2 philic network, exhibiting a microphase-separated, or dual-phase behavior in Pebax matrix. The performance of CO2/N2 separation was increased according to the PBE content, with the maximum selectivity at 5 wt%. The enhancement of Pebax/PBE CO2-philic membrane was attributed to the formation of CO2-philic channel consisting of ether oxygens and triazole groups. The best performance was CO2 permeability of 175.3 Barrer and CO2/N2 selectivity of 48.2.
For facilitated olefin/paraffin separation, poly(ethylene-alt-maleic anhydride)-g-O-(2-aminopropyl)-O′-(2-methoxyethyl) polypropylene glycol (PEMA-g-PPG) is reported by facile, cheap and moderate-condition synthesis. PEMA-g-PPG provided effective polymer matrix for partially polarized silver nanoparticles (AgNPs) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). AgNPs could facilitate olefin transport through π-complexation, while TCNQ activated surface of AgNPs for partial polarization as a strong electron acceptor. The FT-IR and TEM image supported improved interactions between PEMA-g-PPG and AgNPs. The best separation performance was obtained with 1:3 wt ratio of PEMA-g-PPG:AgNPs, showing 7.8 GPU for mixed gas permeance and 17.5 selectivity for propylene/propane.
We present a high-performance polymeric membrane based on self-cross-linkable poly(glycidyl methacrylate-g-poly-(propylene glycol))-co-poly(oxyethylene methacrylate) (PGP-POEM) graft copolymer for CO2/N2 separation. The self-cross-linked membranes can be easily prepared under mild conditions without any additional cross-linking agents or catalyst. We investigated the gas separation performance of the membranes as a function of POEM content in the copolymer. The self-cross-linked PGP-POEM membranes showed an improvement in both permeance and selectivity with increasing POEM content up to 51.2 wt %. The best performance of the membrane was achieved by optimizing membrane thickness, showing a CO2 permeance of 500 GPU (1 GPU = 10-6 cm3 (STP)/(s cm2 cmHg)) and CO2/N2 selectivity of 22.4.
Two emitting compounds, 9,10-bis-[1,1;3,1]terphenyl-5-yl-1,5-di-o-tolyl- anthracene [TP-DTA-TP] and 9,10-bis-phenyl[1,1;3,1]triphenyl-5-yl-1,5-di-o- tolylanthracene[ TPB-DTA-TPB] based on newtwisted core moiety were synthesized through boration, Suzuki reaction, and Sandmeyer reactions. EL performance was improved by varying the chemical structure of the side group. Physical properties such as optical, electrochemical, and electroluminescent properties were investigated. Synthesized compounds were used as an EML in OLED device: ITO/2-TNATA (60 nm)/NPB (15 nm)/TP-DTA-TP or TPB-DTA-TPB (35 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). It was found that TPB-DTA-TPB showed higher luminance efficiency and better C.I.E. value than TP-DTA-TP device.
Three new compounds are synthesized as color filter dyes by substituting a pyridine group into 1,4-position, 1,5-position, and 1,8-position of anthraquinone core moiety. Changes in physical properties of the synthesized compounds according to the substitution position are systematically investigated in terms of optical properties and thermal properties. The extinction coefficient value (ε) of the synthesized materials is extremely high and is above 4.22 in a log scale, and Td is above 300°C with high thermal stability.
A new green light emitting compound based on tris (N-methylindolo) benzene (NMTI), anthracene and pyrene was synthesized. NMTI-An and NMTI-Py were used as the light emitting layer of the OLED element to investigate the luminescence characteristics. The OLED device containing NMTI - NPB luminescent layer and hole transport layer (HTL) showed superior characteristics compared to NMTI-Py. The device exhibited maximum EL emission at 502 nm and 550 nm, CIE coordinates (0.38, 0.48) and a luminance efficiency of 2.06 cd/A. Also, when NMTI and NMTI-An were used as HTL instead of NPB, the device containing NMTI-An emitter showed 2.67 cd/A and 2.29 cd/A in luminescence efficiency.
7-(4-([1,1-biphenyl]-4-yl(9,9-dimethyl-9H-fluoren-2-yl)amino)phenyl)-4-methyl-2H-chromen-2-one (BPFA-C) including coumarin moiety was synthesized through Suzuki aryl-aryl coupling reaction. Optical and electrical properties were examined by UV-visible absorption spectra, PL spectra, and AC-2. UV-visible spectrum of BPFA-C in a film state showed maximum absorption wavelength of 367 nm. PL spectrum of BPFA-C show maximum emission wavelength of 511 nm. BPFA-C showed highly efficient luminescence property. EL spectrum of BPFA-C exhibited a maximum value of 504 nm and BPFA-C device provided luminescence efficiency of 4.59 cd/A, power efficiency of 3.17 lm/W, and CIE (x,y) of (0.25, 0.53) at a current density of 10 mA/cm².
Two new synergists are proposed for pigment dispersion in pigment ink. Benzoic acid was applied to Pigment Yellow 74 (PY-74) and Pigment Yellow 150 (PY-150) as a hydrophilic functional group to synthesize (E)-4-(((3-(2-(2-methoxy-4-nitrophenyl)hydrazono)-4-oxopent-1-en-2-yl)(2-methoxyph enyl)am-ino)methyl)benzoic acid (PY-74BA) and (E)-4-((2,4,6-trioxo-5-((2,4,6-trioxohexahydropyrimidin-5-yl)di-azenyl)tetrahydropyrimidin-1(2H)-yl)methyl)ben zoic acid (PY-150BA). Whereas pigment showed extremely low solubility in water and organic solvents like DMSO, DMF and methanol, two synergists were found to have higher solubility than pigment. This result can be interpreted as reduction of particle aggregation by increased polarity. Two synergists applied to pigment ink are expected to improve dispersion property and storage stability of ink.