Uptake mechanism of IO3 − to NO3 −-hydrotalcite

Abstract

Summary The FT-IR (Fourier transform infrared spectroscopy) spectrum of IO3 − adsorbed in the interlayer of NO3 − hydrotalcite (HTNO3) was determined. The v 3 vibration modes of IO3 − split into two peaks. All peaks caused by adsorbed IO3 − were found to be shifted to the lower wavelength region relative to the peaks observed from IO3 − in the KIO3 crystal. This suggested that IO3 − adsorbed in the interlayer of HTNO3 has asymmetry different from the original C3v symmetrical structure of aqueous IO3 −. The structural position of IO3 − in the interlayer of HTNO3 was optimized using the CASTEP (Cambridge serial total energy package) code. This code is based on density functional theory (DFT) calculations for crystal structures. It was found that the hydroxyl groups bound to O atoms of IO3 − are not uniform. This may lead to the structural change of adsorbed IO3 −.