Elaboración de espumas de carbón a partir de taninos condensados para la recuperación de itrio en soluciones acuosas.

Abstract

In recent years the demand for rare earth elements (REE) has been increasing, since they are widely used in electronics, metallurgy, agriculture and medicine, due to their unique properties. Yttrium (Y+3) is one of the main elements of rare earths, which belongs to the lanthanide family. It is considered polluting because it has caused negative impacts on ecosystems and food quality, caused by the unrestrained exploitation of its deposits and poor extraction methods. Based on these problems, modern science seeks to develop separation technologies that are sustainable and in harmony with the environment. Currently, biosorption is one of the most environmentally friendly technologies, due to the fact that it uses materials of organic origin. In this study, condensed tannins are used for the preparation of gels, since it is an element of vegetable origin. Two adsorbent materials were used: condensed-tannin gel (CTG) and tannin-based carbon foams (ETC). For the ETC, the CTG were subjected to a thermal "pyrolysis" process at a temperature of 800 °C. This treatment makes it possible to transform biomass or various raw materials into by-products and usable energy. For the characterization of the GTC and ECT adsorbent material, the potential of zero charge method (pHpzc) was used. For the adsorption process, a pH study was carried out, in addition, using the non-linear models Freundlich and Langmuir, the equilibrium study was carried out and, also with the Pseudo first order (PPO) and Pseudo second order (PSO) models, the kinetics were studied.