Obtención de materiales compuestos con propiedades magnéticas para la remoción de zinc a partir de residuos lignocelulósicos

Abstract

In this study, composite materials was obtained by the impregnation of magnetite nanoparticles in lignocellulosic wastes for removing zinc from synthetic solutions. Wood shavings from canelo, laurel and eucalyptus with a particle size between 74 to 150 μm were used as matrix. The synthesis of magnetite nanoparticles was performed by co-precipitation from ferric chloride and ferrous sulfate in 100 ml of distilled water at 35 ᵒC with vigorous stirring and argon atmosphere. Subsequently, the addition of lignocellulosic residues was performed at the same conditions to obtain the composite material. XRD analysis was employed to confirm the obtaining of magnetite and the presence of nanoparticles in the lignocellulosic matrix was confirmed by FTIR and SEM. TEM analysis confirmed the nanoparticles diameters about 20 nm. The zinc removal assays were realized at conditions 3 h, 0.7 g and, pH 6 allowed to obtain the percentages of maximum removal 98.95; 98.80 and, 97.61 % for composite materials of laurel, canelo and eucalyptus, respectively. While, for lignocellulosic waste were 60.98; 46.01 and, 33.31 %. From the adsorption isotherms parameters, it was determined that the composites of laurel and canelo fit the model of Freundlich, while eucalyptus fits the Langmuir model. The maximum removal capacities (qm) of materials composed of laurel, canelo and eucalyptus were 28.65; 21.46 and 8.22 mg / g, respectively.