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        검색결과 11

        3.
        2017.11 구독 인증기관·개인회원 무료
        ZSM-5 zeolite membranes can be tuned for hydrophilicity with varied Si/Al ratio allowing dehydration of various organic-water mixtures. α-Al2O3 supports were dip coated by silicalite-1 seed particles, dried (180°C for 12h) and calcined (450°C for 5h) for the secondary growth process. Hydrothermal synthesis of ZSM-5 zeolite membranes was carried out at 180 °C for 48 h. SEM and XRD results indicate excellent crystal morphology with high purity and preferred orientation. Prepared membranes showed a maximum perm-selectivity of 24 at 30°C for H2/SF6 separation. At that condition, H2 and SF6 permeance was 212 and 9 GPU, respectively. It was found that the permeance was higher at low Si/Al ratios, so it is expected that prepared membrane can be applicable for acetic acid dehydration.
        4.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        소수성 ZSM-5 분리막을 결정성장핵의 수열합성 2차 성장법으로 다공성 스테인레스 스틸 지지체의 안쪽에 합성하였으며, 이렇게 제조한 분리막을 이용하여 n-부탄올 수용액으로부터 n-부탄올을 선택적으로 분리하였다. 공급 수용액의 농도 변화 및 운전 온도의 변화에 따른 투과증발 특성을 관찰하였다. 공급 수용액 내의 n-부탄올 농도를 각각 0.001, 0.005, 0.01 그리고 0.015 몰분율로, 운전 온도는 25C, 35℃ 그리고 45℃로 바꾸면서 실험하였다. 운전 온도가 45℃인 실험조건에서 공급측 n-부탄올의 몰분율이 0.001에서 0.015로 증가함에 따라 n-부탄올의 플럭스는 약 2g/㎡/hr 에서 27g/㎡/hr 로 크게 증가하였다. 이 결과로 투과물 내의 n-부탄올의 농도가 0.0016 몰분율에서 0.052 몰분율로 상당히 증가함을 알 수 있었다. 공급 농도가 0.015인 상태에서 운전 온도가 25℃에서 45℃로 증가함에 따라 n-부탄올의 플럭스는 약 13g/㎡/hr 에서 27g/㎡/hr 로 크게 증가하였으며, 투과물 내의 n-부탄올 농도도 따라서 0.045에서 0.052로 증가함을 관찰할 수 있었다.
        4,000원
        5.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        휘발성 유기화합물로서 3가 염소탄화수소인 트리클로로메탄, 트리클로로에탄, 트리클로로에틸렌을 MFI 구조인 소수성 제올라이트 ZSM-5 분리막으로 투과증발을 이용하여 물과의 이성분계 혼합물로부터 선택적으로 분리하고자 하였다. 직경 9.5 mm 다공성 스테인리스 스틸 튜브의 내부 표면에 수열합성법으로 ZSM-5 제올라이트 결정을 성장시켜 박막을 만들어 분리막으로 이용하였으며, 합성된 ZSM-5 제올라이트 분리막으로 공급되는 3가 염소화합물의 농도 및 실험 온도에 따른 분리 특성을 고찰하였다. 3가 염소화합물의 수용액상 농도를 0.0001 몰분율부터 0.001 몰분율로 변화하면서, 또한 실험 온도를 25에서 45℃로 바꾸면서 투과증발 실험을 수행한 결과 트리클로로메탄/물 이성분계에 대하여 약 16~66의 선택도를 얻었으며, 트리클로로에탄/물 이성분계에 대하여 3.3~4.6의 선택도와 트리클로로에틸렌/물 이성분계에 대하여 1.4~8의 선택도를 관찰할 수 있었다.
        4,000원
        6.
        2004.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ga-MFI was synthesized by a hydrothermal process at atmospheric pressure. The effect of mole ratios of reactants on crystallization was also investigated thoroughly. The characteristics of synthesized Ga-MFI was compared with ZSM-5. The synthesis of Ga-MFI was carried out with five different mole-compositions of _aSiO2-_bGa2O3-_cNa2O-_dTPA2o-_eH2O. The synthesized Ga-MFI and ZSM-5 were characterized by XRD and FT-IR. The inorganic cation (Na+) and water played an important role in crystallinity and the organic cation (TPA+) as a template played a great influence on yields. With the increase in the amount of Ga3+, crystallization time was increased. With a fixed SiO2/Ga2O3 ratio of 400, the optimum reaction condition was obtained at H2O/SiO2=30~35, Na2O/SiO2=0.5~0.6, and TPA2O/Na2O=1~1.25. In these cases, the crystallinity and yield were more than 95% and 90%, respectively. By comparing IR spectrum of Ga-MFI with those of ZSM-5 and silicalite, it was found that Ga-MFI showed a unique peak at 970 cm-1, which may be used to identify Ga-MFI from ZSM-5 and silicalite.
        4,000원
        7.
        2000.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        마그네슘 함수 규산염인 사문석으로부터 염산침출하여 얻은 다공성의 침출잔사를 실리카원으로 사용하였다. ZSM-5 제올라이트는 사문석 침출잔사와 알루미늄원인 수산화 알루미늄을 각각 수산화나트륨에 혼합 용해하여 고온고압반응기를 사용하여 수열반응에 의하여 합성하였다. 반응온도와 반응시간, 알칼리 농도 및 하소온도 등을 변화시키며 실험을 행하였으며, 반응온도 170˚C, 반응시간 24시간, 조성 11.7Na2O·Ai2O3·90SiO2·3510H2O·10.8(TPA)2O 그리고 하소온도 600˚C, 3시간에서 가장 높은 결정화도를 갖는 ZSM-5 제올라이트를 합성하였다.
        4,000원
        8.
        2000.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The selective catalytic reduction(SCR) of nitric oxide by ethane in the presence of oxygen was investigated on Cu-ZSM-5, Co-ZSM-5 and Ga-ZSM-5 catalysts over a range of 400, 450 and 500℃. The catalysts were prepared by ion-exchange method. The composition of the reactant gases were 1000 ppm of NO, 1000 ppm of C2H6 and 2.5% of O2, and the reaction was conducted in a fixed-bed reactor at 1 atm. For the 20wt% Co-ZSM-5(50) catalyst, the NO conversion reached up to 100%, while the C2H6 conversion and the CO selectivity were about 50% and 25%, respectively, at 450℃. For the 20wt% Cu-ZSM-5(50) catalyst, the NO conversion and the C2H6 conversion were about 80% and 100%, respectively, but there was no CO produced. The metal ion-exchanged ZSM-5 catalysts exhibited a tendency to increase the NO conversion with the Si/Al ratio of the ZSM-5, that is, NO conversion was inversely proportional to the acidity of the catalysts. But, the effect of the acidity on NO conversion was not so large. From the XRD results of the catalysts before and after SCR reaction it was found that there was no structural change.
        4,000원
        9.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        transition metals(Cu, Co)/ZSM-5 catalyst was made by mechanical alloying method, and their microstructures and repeated usage-properties were investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The conversions ability of NO in the catalyst was measured. A part of ZSM-5 in CO/ZSM-5 composite powders was amorphous and the amorphous phase became less stable with increasing Co content. Conversion ability of NO in 10Cu/ZSM-5 powders decreased from 89% to 12% and that in 10Co/ZSM-5 decreased from 22% to 17% by 7 times conversion tests.
        4,000원
        10.
        1996.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The exhaust gas from vehicle engines and industrial boilers contains considerable amount of harmful nitrogen monoxide(NO) which causes air pollusion and acid rain. To remove NO catalytic reduction processes using Cu ion exchanged ZSM-5 zeolite have been widely studied. In this study, an attempt was made to fabricate Cu/zeolite catalyst by using high energy ball mill. The catalytic performance of ball milled Cu/ZSM-5 zeolites is analyzed and optimum copper contents was determined. The processing variables were reaction temperature and copper contents. Complete removal of NO gas was obtained at the temperature of 553 K on 10wt.% CU/ZSM-5 mechanically alloyed composite powders. Mechanically alloyed CU/ZSM-5 catalyst showed homogeneous distribution of Cu in ZSM-5.
        4,000원