Estudos dos parâmetros para eletrofiação de Ecovio®/PCL contendo carvão modificado na adsorção de tetraciclina

Abstract

New techniques have emerged in the field of environmental science with the aim of developing water treatments using biodegradable materials, such as some polymers, and secondary materials such as household, industrial and agricultural waste. Films with good adsorption capacity of pollutants can be produced by the electrospinning technique using biodegradable polymers. The adsorption of contaminants can also be efficient by means of modified carbon from natural sources. The objective of the present work was to produce Ecovio® and PCL electrospun films, with and without incorporation of functionalized carbon from tilapia bone residue (CAF), for the adsorption of tetracycline (TC) in aqueous solution. Initially, adsorptive tests were performed to select the physicochemical modification of the CAF that obtained the highest adsorption. Then, polymer films were produced with and without the incorporation of CAF, and subjected to adsorption tests at different pHs along with the isolated CAF. The materials were analyzed by means of Optical Microscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). CAF treated with HCl in 150 mesh granulometry obtained the highest adsorptive efficiency and was used in the subsequent tests. The parameters of electrospinning and preparation of solutions presented discrete differences for the obtained fiber diameters. A small reduction in diameters was observed with incorporation of CAF. The electrospinning parameters selected were 14 kV, 1 mL h-1 and 12 cm. The SEM showed that CAF had heterogeneous sites on its surface and, for electrospun films, there was beads formation and differences in the surface of the fibers, according to the solvent used. The FTIR indicated that CAF consists mainly of HAp and collagen. The influence of the pH was verified through adsorptive tests, in which alkaline pH was more efficient, with adsorption of TC (100 mg L-1) of 20.45 mg g-1 (pH 10) and 19.23 mg g-1 (pH 9) for CAF and 19.93 mg g-1 (pH 9) for the Ecovio®85/PCL15/CAF blend of 15% (w/v) with chloroform/DMF solvents. The mechanisms suggested in the adsorption of TC in the present work are diffusion of charges on the surface of carbon and formation of complexes.