Synthesis and characterization of zeolite NaY from rice husk silica

Rice husk silica (RHS) in amorphous phase with 98% purity was prepared from a waste rice husk from rice milling by leaching with hydrochloric acid and calcination. The RHS was used effectively as a silica Source for the synthesis of zeolite Y in sodium form (NaY). The zeolite in pure phase was obtained from a two-step synthetic route in which the starting gels were mixed, aged for 24 It at room temperature and crystallized for 24 h at 90 degrees C. The diameter of single crystal particles from a scanning electron microscope was approximately 1.0 mu m, whereas the average particle diameter from laser diffraction particle size analyzer was approximately 10 mu m because of the agglomeration of small crystals. Longer crystallization time in this route resulted in a mixed phase containing NaY and zeolite P in sodium form (NaP). In addition, a one-step synthetic route (no aging) was studied and the product was also a mixed phase zeolite.