Abstract: Here it is reported that Na-A zeolite can be synthesized by a clear solution. This synthesis method is based on the fact that the condensation reaction of [SiO₂(OH)₂]^2- and [Al(OH)₄]^- occurs readily, however, the condensation reaction of [Al(OH)₄]^- and [Al(OH)₄]^- does not occur. A solution can be prepared in which [SiO₂(OH)₂]^2- ions are surrounded by a large number of [Al(OH)₄]^- ions, so that the condensation reactions of [SiO₂(OH)₂]^2- and [Al(OH)₄]^- produce a large number of [Si(O—Al—(OH)₃)₄]^4- ions, but these [Si(O—Al—(OH)₃)₄]^4- ions are not condensed ulteriorly, so no sediment is formed. In this way, a clear solution is obtained for the synthesis of Na-A zeolite. A high-quality film of Na-A zeolite on the glass or on the porous alumina ceramic tube can be prepared by using this clear solution. 

Key words: Na-A zeolite, zeolite film, aluminosilicate, clear solution, hydrothermal synthesis