Ativação de zeólita natural para preparação de floculante utilizado em tratamento de água

Abstract

In this study, a clinoptilolite type natural zeolite was actived with sodium mono-, di-and tri valent for use as an aid to flocculation in water treatment. The preparation of modified zeolites were conducted by modifying the first natural zeolite with sodium and ammonia salts, thus obtaining a zeolite almost homoionic with a higher ion exchange capacity, and after the modification with calcium, magnesium and aluminum salts, with the objective to study the effect of the charge of the ions used. Atomic absorption analyzes were employed to check the peak adsorption of ions to the zeolite structure. The samples were characterized by: x-ray fluorescence, x-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area. The characterizations showed that the zeolite sample under study has other impurities, modernite zeolite and quartz. The results of x-ray fluorescence, surface area and SEM showed that the zeolite has a low ion exchange capacity and the adsorption with aluminum ions takes place with the formation of multilayer. Analysis Zeta Potential and Isoelectric point were carried out to examine the surface charge of the materials when in aqueous surrounding and showed that the natural zeolite has a negative surface charge and that only by modification with aluminum surface charge has undergone inversion. The study of the features of the modified zeolites was carried out in jar test analysis and found that the natural zeolite, modified with cations forms mono-and di-valent not show satisfactory results in the reduction of color and turbidity, however, it was found that the form zeolite modified with aluminum ions caused the reduction of the concentration of coagulant (alum), and decreased the final color and turbidity.