CRYSTALLIZATION OF ZEOLITE MORDENITE AND ZSM-5 WITHOUT THE AID OF A TEMPLATE

Zeolites ZSM-5 and mordenite were synthesized without the aid of a template, in the gel composition of XSiO2:Al2O3:YNa2O:1500 H2O, where X = 20-40 and Y = 3.5-10.0 at 463 K. After 48 h of crystallisation the aluminosilicate gel system yielded either ZSM-5 or mordenite and their mixtures as zeolitic phases in addition to alpha- quartz depending on the variation in oxide mole composition. Transformation of crystalline ZSM-5 to mordenite was accompanied by a lower yield of solid product as a result of an increase in SiO2/Al2O3 and Na2O/SiO2 ratios in the aluminosilicate gel. At constant Na2O/SiO2 ratio, the decrease in SiO2/Al2O3 in the gel mixture was operative in lowering the product SiO2/Al2O3 ratio. Similarly, at constant SiO2/Al2O3 the increase in Na2O/SiO2 in the gel decreased the product SiO2/Al2O3 ratio. The mordenite obtained was found to be of the small port variety. Crystalline phases obtained were further characterised by XRD, IR, SEM and sorption studies.