Ativação ácida da caulinita in natura e intercalação de potássio

Abstract

Kaolinite is an abundant clay which has a wide range of applications in various sectors of the industry, such as ceramics, paper and fertilizers. In order to extend its application through treatments such as the intercalation with the interaction of the surface hydroxyls with the potassium acetate ion and the acid activation are carried out, allowing an increase in the surface area and in the interlamellar space of the kaolinite crystalline structure. In order to facilitate the process of ion insertion, the acid activation of kaolinite with 10 mol L-1 phosphoric acid and subsequent intercalation with potassium acetate in different concentrations was carried out. The samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), Thermal Analysis (DTA), Dispersive Energy Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) and Flame Photometry. By the diffractograms obtained in the XRD analysis it was possible to prove that the intercalation of the potassium acetate molecule, since there was the appearance of the peak 6.2º of 2θ and the decrease of the peak in 12º of 2θ kaolinite characteristic. In the IVTF spectra there was a decrease in the intensity of the bands relative to the OH present in kaolinite due to interaction with the potassium acetate. The flame photometry has shown that a gradual release of potassium ion occurs over time and acid activation increases the levels of release. However, there was no complete leaching of the ion in the medium, even in 48-hour studies, indicating that they could be applied as possible fertilizers.