Static synthesis of high-quality MCM-22 zeolite with high SiO2/Al2O3 ratio
Static synthesis of high-quality MCM-22 zeolite with high SiO2／Al2O3 ratio

We demonstrate a synthesis method to broaden the range of SiO2/Al2O3 ratio (30-100) of high-silica MCM-22 zeolites by prolonging the aging time of the gel before the crytallization. The synthesis conditions such as silica sources, chemical compositions of initial gel and aging time of gel were investigated in detail. High quality MCM-22 products with various morphologies have been synthesized by optimise their synthesis conditions. Our results show that increasing of the aging time can make the gel be homogenisation and promote their nucleus formation, which may avoid the for-mation of impurity phase and thus broaden the range of SiO2/Al2O3 ratio.