Estudo da remoção do antibiótico amoxicilina em meio aquoso: utilização da perlita expandida e casca de pistache in natura como adsorventes

Abstract

Incorrect disposal of medicines has become an environmental problem, wastewater assessment shows that drugs are present. Antibiotics are constantly modified to fight bacteria and thereby changing the environment in which it is discarded. These are considered complex because their active ingredient is not completely degraded. The mass transfer process for removal of the amoxicillin drug in synthetic solution was evaluated using the fresh pistachio peel and expanded perlite adsorbents. These were characterized by Zero Charge Point Determination (PZC), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The adsorption tests were performed in batch, with variations in time, concentration and temperature. The micrographs revealed a good surface area for both adsorbents, with site diversity. Spectra manifested for pistachio peel and perlite possible functional groups for an interaction with the antibiotic. XRD showed predominantly amorphous structures. The PZC evidenced the preference of interactions for solutions with anionic domains. The adsorption tests followed a fast time and followed a pseudo-second order kinetics for the two adsorbents. The fresh pistachio bark presented an isotherm modeled for Freundlich, with the thermodynamics following an organized pattern, with spontaneous and endothermic reaction of ΔH = 88.305 kJ mol-1. The expanded perlite developed a modeling isotherm for Sips, with a non-spontaneous, organized, endothermic thermodynamic, with ΔH = 27.045 kJ mol-1. Comparison of the characterization of the adsorbent before and after the adsorption process revealed that for the pistachio bark there was a chemissorption and for the expanded perlite a harmony that involved the chemissorption and physisorption occurred. Both adsorbents have been shown to be efficient in reducing the concentration of amoxicillin in solution.