Abstract: The reaction of NaYzeolite with an aqueous oxalic acid solution under mild conditions yields zeolite with framework containing hydroxyl nests which are dewatered to lead tothe formation of the secondary pore when the zeolite is heated above 300℃.As the oxalicacid feed increases, the degree of dealumination of the zeolite increases, the crystallinity isreduced, but about 2O% framework aluminium is removed retaining 95% crystallinity whichdepends mainly on buffering of the system of the zeolite dealumination.There is a very goodlinear relationship with a slope of about 0.25 between mole numbers of the aluminium removed from the zeolite framework and those of the H+ depleted during the reaction of NaYwith oxa1ic acid.This result indicates that the eaction of an aqueous oxalic acid solution withNaYis stoichiometric by four H⁺ attack on one aluminium of the framework.

Key words: NaY zeolite, Oxalic acid, Dealumination, Hydroxy nests, Secondary pore