Hierarchically multifunctional K-OMS-2/TiO2/Fe3O4 heterojunctions for the photocatalytic oxidation of humic acid under solar light irradiation

A multifunctional heterojunctioned K-OMS-2/TiO2/Fe3O4 (KTF) nanocomposite was successfully synthesized using a combination of hydrothermal and co-precipitation techniques. The resultant sample was characterized by XRD, FESEM, TEM, N-2 adsorption, XPS and VSM. Its photocatalytic activity was demonstrated in the photocatalytic degradation of humic acid (HA). Morphology characterization showed the hierarchical structure of the synthesized material, and XRD results revealed that both the rutile and anatase TiO2 structures are present in the sample. The average pore diameters and BET surface area of the synthesized KTF heterojunctions were 40nm and 134.42 m(2)/g, respectively. XPS spectra confirmed the presence of Fe3O4 and TiO2 in the synthesized material, and the valences of Mn were kept at +3 and +4 after the grafting of Fe3O4 and TiO2. The synthesized material showed good magnetic response and photocatalytic activity under simulated solar light irradiation, and 85.7% of HA was decomposed after 120 min in the presence of KTF nanocomposites. The reusability study suggested that the magnetic recovered material was stable enough for multiple recycling usages, verifying its potential application in water purification. (C) 2012 Elsevier B.V. All rights reserved.