Síntese e caracterização de compósitos hidrocarvão/simonkolleite e seus precursores para aplicação na remoção adsortiva do antibiótico Rifampacina em solução aquosa

Abstract

Brazil is one of the largest sugarcane producers in the world, and Alagoas is the state in the Northeast region which presents the largest contribution in produced tons. After the process of extracting the juice for production and sugar and alcohol, a by-product is generated, sugarcane bagasse, this residue has a bias for various applications, such as burning to generate electricity, and more recently has been studied its application as an adsorbent agent. An alternative to improve the characteristics of biomass is to convert the residue into hydrochar (HC), as the conversion ensures a more stable and more efficient matrix for the adsorption process. Hydrochar can also be used as a support for materials with catalytic properties, in the case of this study simonkollite (SK). In this context, three composites and their precursors were synthesized, aiming at the deposition of simonkollite on sugarcane bagasse hydrochar. Then, the efficiency of the materials for the removal of rifampicin from an aqueous effluent was evaluated. Rifampicin is a drug used to treat tuberculosis and leprosy and is part of the class of emerging pollutants (EP). The association of SK with hydrochar can lead to greater efficiency for the treatment of effluents containing EP. In this study, three synthesis routes of the composites were investigated, by co-precipitation, manual mixturation and addition of SK in the HC preparation step. The synthesized materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA and DrTGA), Scanning Electron Microscopy (SEM), Optical Microscopy (OM) and Spot Zero Charge System (PCZ). For the adsorptive tests, in distilled water, at pH equal to 9, a percentagem of removal of rifampicin, Coprecipitate and Manual Composites, equal to 72.1 and 71.3%, respectively, was obtained, while for Hydrocarbon, SK and ZnO composite, at pH equal to 5, showed a reduction of 70.4, 37.23 and 72.4%, respectively. The models that were suitable for adsorption kinetics and adsorption isotherm were the pseudo-second order and the Sips, in that order. The tests in real matrices reported similarity with those performed in the model matrix, indicating the possibility of application in different aqueous matrices, when compared to the model matrix (distilled water). The results showed that the methods of co-precipitation and manual mixing were efficient for the deposition and anchorage of SK on the hydrochar.