Caracterização e aplicação da argila expandida na absorção de íons metálicos potencialmente tóxicos

Abstract

The application of ceramic materials in the removal of potentially toxic metal ions in public water supply has been widely studied due to its low cost, easy to obtain, relatively simple operating technique for its use, minimizes sludge generation, does not generate toxic byproducts and because it presents high efficiency. In this work, we studied the adsorption of solutions of Pb2+, Cd2+, Ni2+ and Ba2+ ions in expanded clay. In the experimental part, the Rotated Central Composite Design was used as a statistical technique, having as variables the concentration of metals, the stirring time and the granulometry of the clay. Subsequently, for the refinement of the results, the Factorial Planning was used in two variables (agitation time and particle size). For both assays, it was worked with constant pH and temperature. The quantification of ions in the sorption experiments was performed by atomic emission spectrometry, Microwave Plasma-Atomic Emission Spectrometer (MP-AES). The microstructural and chemical characterizations of the expanded clay were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), respectively. Adsorption studies showed that the model that best fit the experimental data for both ions was Langmuir. The results obtained in the adsorption tests with the optimized variables showed the viability of the application of expanded clay in the adsorption of potentially toxic metal ions in public water supply, with removal efficiency over 90% for Pb2+, Cd2+, Ni2+ and Ba2+ ions.