Caracterização, beneficiamento e aplicação da palygorskita como adsorvente de amônio em meio aquoso

Abstract

The purpose of this research was the characterization, processing and application of a new mineral occurrence of palygorskite in the region of Guadalupe-PI/Brazil. The sample was submitted to processings teps such as milling and wet magnetic separation, in addition to different granulometric classifications, it was characterized by X-ray diffraction (XRD), Fourier transforminfrared (FTIR), X-ray fluorescence spectrometry (XFR), particle size distribution by light scattering, scanning electron microscopy (SEM), determination of cation Exchange capacity (CEC), thermogravimetric and thermodifferential analysis (TG-DTG), surface charge measurements by Zeta potential and determinationof surface area (BET) andpore volume (BJH). According to the results, the sample consists of palygorskite with kaolinite, quartz and goethite as impurities, the presence of iron in the sample canals ooccur by isomorphic substitution given its presence after processing. It was determined that the processed sample has 90% of the particles smaller than 70 µm, preserving its fibrous habit. This sample has thermal stability up to approximately 400ºC, a negative surface charge in the pH range between 2.2 and 13.59 and a surface area of approximately 142.07 m2 g-1. CEC reached values close to 41 meq 100 g-1. According to the characterization results, the application of the sample in the adsorption of ammonium contained in liquid swine (DLS) slurry was evaluated. Thus, accordingto a 23 factorial design witht riplicate at the central point, it is concluded that 2 g of palygorskite sample is capable of adsorbing 63.3% of ammonium contained in synthetic ammonium effluent, N-ammonia, in a batch system, when the concentration of the solutionis 20 mg L-1, the pH is close to 4 and the conditioning time is 24 h.