Adsorção de íons de cádmio a partir da Hidroxiapatita e do Biovidro dispersos na Blenda Polimérica (PVA/Amido)

Abstract

The removal of toxic metals from wastewater is of great interest in the study of water pollution. Among the various metals known to be highly toxic is cadmium, which is considered one of the most dangerous substances and can cause serious damage to the kidneys and bones. The adsorption process has been used as an effective method for the removal of metallic ions. An alternative to the use of adsorbents in powder form is their use in conjunction with other materials. The aim of the present study was to develop polymer blends (PVA/Starch), with hydroxyapatite (HAP) and bioglass (BV) dispersed in the medium for the removal of cadmium ions. The characterization of the powders and the polymer blends was carried out by different techniques: Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray Fluorescence Spectrometry FRX), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Determination of Zeta Potential. The adsorption tests were carried out in order to study the kinetics and the equilibrium in the adsorption of the metallic ions, as well as a factorial planning through the software Design Expert. Characterization analyzes show that the adsorbent materials are suitable for use in the removal of heavy metals. The kinetic data showed better correlation with the pseudo-second order velocity equation and the experimental points conformed to the Freundlich isothermal model. The experimental design presented a coefficient of determination (R²) of 0.9826 and 0.9999 for the polymer blends PVA/Starch/HAP and PVA/Starch/BV, respectively, with a confidence level of 95%. Thus, the adsorption of the cadmium by the polymer blends with HAP and BV in aqueous solution proved to be efficient, making the process viable for the removal of heavy metals.