Hierarchically 3D flower-like alpha-Fe2O3 microstructures have been synthesized through a urea-assisted hydrothermal synthetic route. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The as-prepared product was consisted of hierarchically flow-like microstructures assembled from nanopetal subunits. The effects of the urea and NaOH on the morphology of the products were systematically studied, and a possible formation mechanism of the alpha-Fe2O3 microflowers was proposed based on the experimental results. These flower-like alpha-Fe2O3 microstructures were used as adsorbent for water treatment, and the results revealed excellent performance for heavy metal ion removal. With maximum capacities of 41.46 and 33.82 mg g(-1), for As(V) and Cr(VI), respectively, such flower-like alpha-Fe2O3 microstructures are expected to be an attractive adsorbent for the removal of heavy metal ions from water. (C) 2013 Elsevier B.V. All rights reserved.