Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Synthesis of zeolite A membranes on alumina support by hydrothermal reaction

수열반응에 의한 알루미나 지지체에 제올라이트 A 박막의 합성

  • Ko, Tae-Seog (Department of Jewelry Design and Metalsmithing, Dongshin University)
  • 고태석 (동신대학교 귀금속디자인세공학과)
  • Published : 2007.06.30
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Abstract

The synthesis of NaA zeolite membrane on a porous alumina support from clear solution by using hydrothermal reaction was investigated. Effects of reaction temperature, reaction time and seeding for transformation of zeolite A membrane and powder which are produced in the reactor were monitored through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The transformation process of producing Zeolite A membrane starts from the formation of the compact and continuous membrane on the surface of porous support from clear solution. The large Zeolite A poly-crystal was then farmed through the dissolution process. Finally, the process was advanced from sodalite to amorphous. In case of powder, sodalite is formed in the early stage of reaction because of surrounding space difference between membrane and powder crystal. Discrete surrounding space of powder crystal makes easy to transform to sodalite. From Zeolite A to amorphous through transformed product was rapidly advanced at high temperature while the membrane with somewhat low coverage was obtained at low temperature. A compact and continuous zeolite A membrane was synthesized at $120^{\circ}C$ in 12-hour period.

수열합성 장치를 이용하여 종자 결정이 도포된 알루미나 지지체 위에 제올라이트 박막을 합성하였다. X-선 회절 분석과 전자현미경 사진을 이용하여 반응기 내에 생성된 제올라이트 A 분말과 제올라이트 A박막의 생성과 전이 생성물에 대해 합성온도, 합성시간, 종자결정의 영향에 대해서 고찰하였다. 제올라이트 A박막의 생성은 지지체 표면에 도포된 종자 결정에서 치밀한 연속적인 박막이 형성된 다음 용해과정을 거쳐 결정의 크기가 큰 다결정 층을 형성하고, 최종적으로 소다라이트를 거쳐 무정형으로 진행하였다. 반면에 분말에서는 반응초기부터 소다라이트가 관찰되는데 고정된 제올라이트 A 박막과 다르게 결정주위의 공간적인 차이에 의해 소다라이트가 생성하기에 용이한 공간을 갖기 때문에 소다라이트가 쉽게 생성되는 것으로 생각된다. 합성온도가 높으면 짧은 시간 내에 전이 생성물을 거쳐 무정형으로 진행하였고 온도가 낮으면 합성 시간이 길고 피복도가 다소 낮은 제올라이트 A 박막을 얻었다. $120^{\circ}C$, 12시간에서 피복도가 높은 치밀한 제올라이트 A박막을 합성하였다.

Keywords

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