Synthesis of omega zeolite: Effects of nucleation gel

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Synthesis of omega zeolite: Effects of nucleation gel (EN)

Evmiridis, N. P. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Evmiridis, N. P. (EN)

A method is reported for preparation of phase-pure omega zeolite. It involves crystallization at 120 degrees C of a mixture prepared from an aged nucleation gel (15.0Na(2)O-Al2O3-15.0Si(2)O320H(2)O, similar to 40 days at 35 degrees C) and a water-free aluminosilicate glycerol gel (10.0Na(2)O-Al2O3-13.9Si(2)O-100.0 glycerol). Crystallization processes with use of the nucleation gels after various periods of ageing were studied. It was found that long ageing time of the nucleation gel enhanced the crystallization rate of omega zeolite and suppressed the occurrence of analcime phase. At 90 degrees C and 150 degrees C, syntheses by use of the sufficiently aged nucleation gel were also investigated. At high temperature, crystallization of omega zeolite was faster but analcime phase occurred also. At low temperature, crystallization rate was slow and omega zeolite was the only resulting crystalline phase. The IR features of faujasite phase could be observed in the nucleation gel after about 5 days of ageing at 35 degrees C, however, the synthesis data showed that the use of such nucleation gel did not lead to formation of faujasite phase even as metastable intermediate crystalline phase. (EN)

kinetics (EN)

Catalysis by Microporous Materials (EN)



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