Bentonites functionalized by impregnation with TiO2, Ag, Pd and Au nanoparticles

This work aimed to characterize bentonites with different features and origins (Brazil, Argentina, Italy and United States) that were impregnated with Ag, TiO2, Pd and Au nanoparticles. Either commercial (TiO2) or synthesized (Ag, Pd and Au) nanoparticles (NP) were used and characterized by DLS and XRD. Subsequently, the dispersed NP was impregnated on bentonite by two alternative methods, imbibition or dipping. The efficiency of impregnation of bentonite by metallic nanoparticles was finally tested by ICP-OES, which was over 90% in all cases. Particularly, Ag nanoparticles showed an impregnation efficiency above 99%, as confirmed by SEM-FEG. To improve impregnation, a thermal pretreatment for the bentonites was necessary at 700 degrees C. Both impregnation methods resulted in a suitable distribution and stability of Ag nanoparticles.