Synthesis and characterization of Li-type EDI zeolite

A Li-type EDI zeolite (Li-EDI) was Successfully synthesized in the Li2O-Al2O3-SiO2-H2O system using a silica-alumina mixed sol as the starting material in the absence of other chemical species. The characterization of the obtained Li-EDI was compared with that of the Li-exchanged Linde F zeolite (K-type EDI zeolite). Starting gels with the batch composition of xLi(2)O center dot Al2O3-2SiO(2)-275H(2)O (x = 2-5) were prepared by adding a LiOH solution to a silica-alurnina mixed sol. A hydrothermal reaction of the gels was carried out at various temperatures. Li-EDI formed from all of the batches in the range of 60-100 degrees C. However, the ABW-type zeolite co-crystallized in the composition of Li2O/Al2O3 of 2.0-3.0 above 90 degrees C. The crystal morphology of Li-EDI was a prism shape. The average particle size of Li-EDI is 0.69 mu m in length and 0.23 mu m in width. The crystal structure of the Li-EDI collapsed at 300 degrees C, which indicated that the thermal stability of Li-EDI is significantly lower than that of the Linde F zeolite, which is stable LIP to 1000 degrees C. (c) 2005 Elsevier Ltd. All rights reserved.