alpha-Fe2O3/g-C3N4 composites with heterojunction were prepared by facile one-pot synthesis using ferric chloride and dicyandiamide as precursors. The newly formed composites were applied to remove arsenic from aqueous solution for the first time through synchronous visible light catalysis oxidation and adsorption. alpha-Fe2O3/g-C3N4 composites were characterized by wide-angle X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, and BET surface analysis. Under visible light irradiation, As(III) was oxidized to As(V) efficiently on the surface of alpha-Fe2O3/g-C3N4. In addition, the oxidized arsenic could be adsorbed in situ, resulting in the effective arsenic removal. The enhancement of photocatalytic activity the composites was attributed to the construction of heterojunction between alpha-Fe2O3 and g-C3N4. A possible oxidation mechanism of the as-composites for As(III) under visible light irradiation was also elucidated. (C) 2017 Elsevier B.V. All rights reserved.