Nanometer calcium titanate immobilized on silica gel G (SGCTO) was prepared by the sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its application in speciation of Cr(III) and Cr(VI) from water was studied. Adsorption and elution were investigated under different conditions. The results showed that the nanometer calcium titanate was immobilized on the silica gel G firmly, becoming a new adsorbent. At normal temperature, two forms of chromium show different adsorption capacities at different pH values, that is, Cr (III) selectively retained at pH 8–14, but Cr(Ⅵ) can’t be adsorbed. Whereas Cr (VI) retained at pH 1, but Cr(Ⅲ) can’t be adsorbed. Hence complete separation of the two forms of chromium is possible. Retained Cr(III) and Cr(VI) were eluted with 1 mol•L−1 HCl and 2 mol•L−1NaOH, respectively. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The method was successfully applied for the speciation of chromium in environmental water samples.
Production and characterization of films from nanocomposite coating of sunflower seeds