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HWAHAK KONGHAK,
Vol.29, No.5, 566-573, 1991
Vol.29, No.5, 566-573, 1991
염산 및 불산처리 모더나이트의 흡착특성
Characteristics of Adsorption on Mordenites Treated by Hydrochloric Acid and Hydrofluoric Acid
수소형 모더나이트를 각각 염산과 불산으로 처리하여 일련의 시료를 얻고 질소흡착량에 의한 세공구조, X-선회절에 의한 구조변화, NMR에 희한 알루미늄 제거상태 및 시클로헥산의 흡착특성을 연구하였다. 염산처리의 경우 실리카/알루미나비가 약 30정도이면 이차세공이 형성되었고 알루미늄이 추출되면서 격자수축이 일어났다. 불산처리의 경우도 규소가 동시에 추출되며 이차세공이 형성되었다. 염산처리시는 알루미늄의 추출로 흡착 평형상수는 계속하여 감소하나 초기흡착열은 최소점을 보이고 있다. 그러나 불산처리시는 최대점과 최소점을 보이는 것은 구조의 심한 침식으로 세공에 큰 변화가 생기고 동시에 새로운 강한 흡착점이 형성되기 때문이라 할 수 있다.
A series of aluminum-deficient mordenites were prepared by treating hydrogen mordenites with hydrochloric acid and hydrofluoric acid, respectively. Isotherms of nitrogen adsorption, XRD analysis, silicon NMR, and characteristics of cyclohexane adsorption were studied. Mordenites treated by hydrochloric acid formed secondary pores at more than SiO2/Al2O3 of 30 and the crystal lattice contracted by removing frame-work aluminum. Modernites treated by hydrofluoric acid made also secondary pores by extracting framework silicon simultaneously. For the treatment with hydrochloric acid, initial equilibrium constant, k1 decreased continuouly by removing aluminum but initial heat of adsorption, q1 showed a maximum point and a minimum point. The maximum point would be explained by the improvement of site efficiency due to the enlarged pores. The minimum point could be said by the change of surface property due to the erosed surface of the crystals which revealed new strong adsorption sites.
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