Degradation of 1,4-dioxane by biochar supported nano magnetite particles activating persulfate

Nano magnetite biochar composite (nFe(3)O(4)/biochar) was synthesized and used to activate persulfate for the degradation of 1,4-dioxane. Analytical techniques using X-ray diffraction (XRD), fourier transform infrared analysis (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) indicated that nFe(3)O(4) was spherical and successfully loaded onto the surface of biochar. The results of batch-scale experiments illustrated that the 1,4-dioxane degradation efficiency in aqueous phase was 98.0% after 120 min reaction with the composite mass ratio of 1:1 between nFe(3)O(4) and the pine needle biochar pyrolyzed at 400 degrees C (P400) under the initial neutral pH. An electron paramagnetic resonance (EPR) study, free radical quenching experiment and XPS analysis were undertaken to illustrate the mechanism of persulfate activation by nFe(3)O(4)/biochar. Under acidic and neutral conditions, the predominant free radical was SO4 center dot- whereas (OH)-O-center dot and SO4 center dot- predominated when the initial pH was 9.0. The XPS analysis indicated that Fe(II) and oxygenated functional groups activated persulfate. In addition, carbon-carbon double bonds would be transformed into ketone and quinone which could activate persulfate during the reaction. (C) Crown Copyright 2017 Published by Elsevier Ltd. All rights reserved.