Photocatalytic activity of Fe/Ti-based compounds obtained from ferro-titaniferous mineral sands via a simple soft chemistry route

Abstract : Fe/Ti-based compounds were synthesized from ferro-titaniferous mineral sands using aqueous oxalic acid under subcritical water (sCW) conditions (135°C/50 bar/4 h) and their photocatalytic activity was evaluated against methylene blue or caffeine under UV-A and visible radiation. The X-ray diffraction and Raman spectroscopy analyses revealed that the assynthetized compounds were mainly comprised of ferrous oxalate, followed by titanium dioxide. This proved the complete transformation of the mineral precursor within 4 h using oxalic acid/sCW as the reaction medium. The photocatalytic studies showed that methylene blue and caffeine were photodegraded under UV-A and visible radiation by the as-synthesized Fe/Tibased compounds. Methylene blue removal was up to 92.8 and 97.4% after 6 hours under UV-A or visible irradiation, respectively. Caffeine removal, however, reached 69.3 and 59.6% after 16 h of exposure to UV-A and visible light, respectively. The as-synthesized compounds can be potentially used as a ferrous-based catalyst in heterogeneous photocatalysis for decontamination of water systems from organic pollutants.