Development of nanostructured materials incorporated with bixin and extracting agents for metal removal from aqueous matrices

The Rio Doce basin in the southeastern Brazil, located on the states of Minas Gerais and Espírito Santo, suffered of one of the greatest environmental disasters in history. The disruption of the Fundão tailings dam in 2015 triggered a spill of a large volume of mining waste in the river. In this context, a new nanostructured materials composed by the polymer polycaprolactone nanofibers incorporated with bixin and common extracting agents were studied in metal recovery process. The materials were created by utilizing the electrospinning technique, where thesorbentwas incorporated on both sides of an iron mesh surface. The goal of this project was to optimize the following parameters: pH; concentration of bixin and different extracting agents (1-(2-pyridyl-azo)-2-naphthol (PAN) and 1-nitroso-2-naphthol(1N2N)); deposition time of nanofibers; kinetics of metal removal and adsorption isotherm, in order to reach high metal percentage removal (%R) from aqueous matrices. The best conditions for iron removal were using a nanofiber incorporated with bixin and PAN, with 20 minutes of deposition time, at pH=6, in which %R equals to (81.5±0.9)% was achieved (Fig.1). In the kinetic studies, an adsorption plateau with %R=72.3% was reached at 240 minutes of contact between the solution and the nanofiber (Fig.2). In addition,the nanofibers were also evaluated for the recovery of aluminum and manganese, in which high values of adsoption were not observed, demonstrating a selectivity of this material for iron recovery.