Effect of ethanol as an additive on the morphology and crystallinity of LTA zeolite

In the present work detailed investigation was made to ascertain the effect of ethanol addition on morphology, phase purity and crystallinity of LTA zeolite. The effect of addition time of ethanol during the reaction mixture preparation was also studied. The synthesis of LTA zeolite was made using inorganic sources of aluminium and silicon in an ethanol-Al2O3-SiO2-Na2O-H2O system. Micron sized distorted cubic shape LTA zeolite along with sodalite disc like clusters were attained on the addition of ethanol before mixing of sodium aluminate with sodium silicate whereas the knobbed surface spheres were obtained when ethanol was added after mixing of same. The addition of ethanol just after the sodium aluminosilicate gel formation (i.e. after the addition of alkali solution to the resultant mixture of sodium aluminate and sodium silicate) also leads to the formation of LTA zeolite crystals along with sodalite but at later stage of crystallization. Thus, the present study reveals that the addition of ethanol makes predominant impact on the LTA zeolite cubic crystal formation and it also provides better understanding of nucleation, crystallization and morphology of LTA zeolite synthesized in the presence of ethanol.