Síntese de hidróxidos duplos lamelares (HDL) para a adsorção de herbicida e obtenção de HDL a partir do material catódico de baterias exauridas para a aplicação como eletrodo

Abstract

In this work, the use of Lamellar Double Hydroxides (LDH) as adsorbents of 2,4- Dichlorophenoxyacetic (2,4-D) pesticide in contaminated water was investigated. From the XRDs of the LDH, higher molar ratios of Co2+ and Al3+ metalic cations cause a decrease in the intensity of the diffraction peaks due to the high density of the Co2+ octahedra in the interlamellar layer and the molar ratio of 2:1 showed characteristic diffraction peaks of the hydrotalcite-like structure. In the investigation of the [Co-Fe-Cl] and [Co-Al-Cl] LDH structures, both obtained a single phase of the hydrotalcite-like structure. In the study of the influence of anions (Cl-/NO3-/SO42-) on the structure of LDHs, that of [Co-Al-SO4] had the lowest baseline spacing J(003) when compared to the others. LDH [Co-Al-Cl] synthesized by the co-precipitation method at constant pH 8.0 ± 0.5 was the one that presented the nearest unit cell parameters when compared to those of hydrotalcite (JCPDS 14-191). The pH of the solution was maintained below the pH of the zero charge point (5.99) of the LDH to ensure greater adsorption efficiency with 2,4- D (anionic herbicide). From the adsorption parameters optimized by the chemometric planning, it was possible to obtain retention 99.56% of the 2,4-D by LDH [Co-Al-Cl] synthesized at constant pH 8.0 ± 0.5. The [Co-Al-Cl] LDHbattery obtained from the cathode material of the exhausted lithium ion batteries by methodology 02 (recovery of LiCoO2 with the addition of salt AlCb.6H2O) and after the hydrothermal treatment showed diffraction peaks characteristic of the hydrotalcite structure. From the LDHbattery obtained from the cathode material, conductive hybrid materials were synthesized having organotin, 2,5-dimercapto-1,3,4-thiadiazole as bridging agent between LDHbattery [Co-Al- Cl] and polyaniline. The cyclic voltammograms of the LDHbattery/PDMcT/PAni ternary composite presented an anodic charge higher than those obtained for its constituent materials and a predominantly faradaic profile with good electrochemical stability, indicating a possible application of this material as cathode in secondary batteries. It was concluded that LDH [Co-Al-Cl] is a promising material for several applications, among them: the adsorption of organic and inorganic pollutants and electrodes of energy devices.