Single-step process without organic template for the formation of zeolite A from RHA

Dice-shaped zeolite A (NaA) was prepared via direct dissolution of rice husk ash (96.5% SiO2) in the presence of NaOH and sodium aluminate solution by autoclave process at 90 degrees C/6 h without using any templating agent. The prepared particles were characterized by DTA/TG, XRD, FTIR, N-2 adsorption-desorption physisorption analysis, FESEM, and TEM. XRD results confirmed crystallization of pure NaA zeolite phase. FTIR study shows the characteristic bands at 554 cm(-1) for double 4 membered ring (D4R) of NaA zeolite. The total BET surface area of the product was found to be 31.6 m(2) g(-1). FESEM and TEM images show dice shaped NaA particles of size around 1 mu m which is formed via oriented crystalline aggregation of primary particles (30-40 nm). A tentative mechanism was proposed for the formation of NaA crystals through direct dissolution of rice husk ash. The synthesized NaA zeolite could be used for purification of alcohol and separation of toxic and radioactive ions from waste water via a cost-effective process