Application of ZSM-5 and ZSM-12 zeolites (in sodium and ammonical forms) in the barium adsorption

Heavy metals are often released into aquatic environments through various sources of industrial processes. However, conventional treatment technologies demand high cost and/or are inefficient for the recovery of these resources. In this context, the technical application of adsorption has been highlighted by its simplicity and practicality, especially when zeolites are used as adsorbents due to their excellent physicalchemical and textural properties, among them: their high availability, high selectivity and low cost. The present work characterized and evaluated the performance of Na-ZSM-5, Na-ZSM-12, NH₄-ZSM-5 and NH₄-ZSM-12 zeolites on barium adsorption as an alternative for the treatment of produced water. The Na-ZSM-5 and NaZSM-12 zeolites were synthesized by the hydrothermal method and subjected to ion exchange to obtain the ammoniacal form (NH₄-ZSM-5 and NH₄-ZSM-12). The characterization was done by: DRX, SEM, FRX and Adsorption / Desorption of Nitrogen, and barium concentration was measured by Atomic Absorption Spectroscopy (AAS). The adsorption studies were conducted under agitation at the times of 1, 6, 12 and 24 h. The results were promising for this application, because the Na-ZSM-5 zeolite presented the highest adsorption capacity, a fact related to its textural properties (volume and area of micropores). (author)