Influences of Metal Chlorides and Sulfates on the Formation of Beta-FeOOH Particles by Aerial Oxidation of FeCl2 Solutions

Abstract

To investigate the influences of metal ions on β-FeOOH formation, the β-FeOOH particles were prepared by aerial oxidation of solutions in the presence of chlorides and sulfates of Ti(IV), Fe(III), Cu(II), and Ni(II), and at different metal/Fe atomic ratios of 0-0.1 and characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma, thermogravimetry and differential thermal analysis, and adsorption. The produced particles contained a large quantity of Ti(IV) and Cr(III) but little Cu(II) and Ni(II). All the added metal chlorides and sulfates made the formed particles less crystalline. The sulfate and chloride of Ti(IV) inhibited the formation of β-FeOOH at a high Ti/Fe by a marked depression of solution pH by hydrolysis of Ti(IV). The metal sulfate ions effectively reduced the crystallinty of β-FeOOH to give highly microporous particles. The strong inhibitory effect of on the crystallization of β-FeOOH can be ascribed to the adsorption of on the primary particles. This is also evident from the high content of in the formed particles. © 2004 The Electrochemical Society. All rights reserved.