"The process which involves ionic exchange was applied with the use of a Mexican zeolitic mineral (Taxco-Guerrero) to remove Zn, Cd, and Ni from an aqueous solutions. Mineral zeolitic samples in their sodium form were put in contact with Zn(NO3)2, Cd(NO3)2 and Ni(NO3)2 solutions of 0.01 N for 8 days...