Síntese do compósito de quartzito-carbono e avaliação do seu potencial para adsorção de azul de metileno

Abstract

The indiscriminate release of effluents containing dyes by the industry has, over the past few years, become a factor of great risk to the environment. It is necessary to develop sensitive and effective methods for the removal of these contaminants disposed in industrial effluents and waste (aqueous main). Methods that involve precipitation, coagulation and filtration, can be listed as viable alternatives for the treatment of these effluents. However, these methods present problems related to the excessive generation of sludge and tailings. To circumvent this limitation, a technique with considerable cost-efficiency for the treatment of industrial effluents would be the process of adsorption removal. This work sought to synthesize, characterize and evaluate the potential of the quartzite-carbon composite as an adsorbent for the methylene blue textile dye. The composite was prepared using waste cut from quartzite and sucrose. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with dispersive energy spectroscopy (SEM / EDS), infrared absorption spectroscopy with Fourier transform (FTIR) and thermogravimetric analysis (TG / DTG). The adsorption experiments were carried out in batch. The experimental data were adjusted to the kinetic (Pseudo-first order, pseudo-second order, Elovich and Avrami), Weber and Morris and equilibrium models (Langmuir, Freundlich, Sips, Temkin, Redlich-Peterson). The adjustments showed a balanced adsorption ruled by Langmuir, with a maximum adsorption capacity (qmax) of 11.63 mg g -1 at 25 ° C. The adsorption kinetics followed Avrami's considerations for fractional order kinetics. Multiple steps govern the adsorption process, as shown by the fit to the Weber and Morris model. The global process is endothermic and spontaneous. The results showed that the quartzite / carbon composite has adequate characteristics to be used as an adsorbent for the decontamination of effluents.