Preparation and characterization of a novel magnetic biochar for arsenic removal.

A magnetic biochar based adsorbent with colloidal or nanosized γ-Fe(2)O(3) particles embedded in porous biochar matrix was fabricated via thermal pyrolysis of FeCl(3) treated biomass. The synthesized samples were studied systematically by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, selected-area electron diffraction pattern, scanning electron microscopy, energy-dispersive X-ray analysis, superconducting quantum interference device, and batch sorption measurements. The characterization analyses showed that large quantity of γ-Fe(2)O(3) particles with size between hundreds of nanometers and several micrometers tightly grow within the porous biochar matrix. Biochar/γ-Fe(2)O(3) composite exhibited excellent ferromagnetic property with a saturation magnetization of 69.2emu/g. Batch sorption experimental results showed that the composite has strong sorption ability to aqueous arsenic. Because of its excellent ferromagnetic properties, the arsenic-laden biochar/γ-Fe(2)O(3) composite could be easily separated from the solution by a magnet at the end of the sorption experiment.