Nanoscaled alpha-FeOOH (goethite) with controlled morphology was synthesized via hydrothermal reaction at 145-155 degrees C from ferrous ions and an oxidant in the presence of a cationic surfactant. The formation of alpha-FeOOH was confirmed by X-ray diffraction (XRD), Mossbauer spectroscopy, FT-IR analysis and visible diffuse reflectance spectroscopy. The morphology of the product was analyzed by transmission electron microscopy (TEM). The particles obtained by the proposed method have a medium size of about 35 nm. The proposed growth mechanism takes into account two possible simultaneous pathways consisting of direct electrostatic interaction between FeOH groups and cetyltrimethylammonium bromide (CTAB) and adsorption of bicarbonate ions on the alpha-FeOOH surface followed by complexation of CTAB through ammonium head groups. (C) 2012 Elsevier B.V. All rights reserved.