Magnetic amendment material based on bio-char from edible oil industry waste. Its performance on aromatic pollutant removal from water

Abstract

Bio-chars produced from the pyrolysis of sunflower seed hulls are investigated in the context of adding value to edible oil industry waste. Magnetic bio-chars are obtained to employ them for the aqueous adsorption of guaiacol, which is a model molecule of pollutants in water. Two magnetization methods are followed to get a series of magnetic bio-chars, one based on the pyrolysis of sunflower seed hulls previously washed with FeCl3·6H2O solutions (MBFs) and the other one consisting of magnetization of the bio-char obtained from the pyrolysis of the hulls pretreated with ZnCl2 (MBZ). A full characterization of the samples is carried out by Scanning Electronic Microscopy (SEM), X-Ray Diffraction (XRD), Atomic Absorption (AA), Fourier Transformed Infrared spectroscopy (FTIR), and N2 sorptometry. Selected magnetic bio-chars are tested for the adsorption of guaiacol in water with four models: Langmuir, Freundlich, Sips and Temkin. The best performance is assigned to the sample MBF5 containing 15.2 Fe %wt. with a maximum adsorption capacity of 48.49âmg/g and a heterogeneous surface according to Sips model. Temkin model predicts physisorption as guaiacol surface interaction presenting a b parameter of 15.87âJ/mol.