Microporous SiO2-TiO2 nanosols pillared montmorillonite for photocatalytic decomposition of methyl orange

Layered nanohybrid, SiO(2)-TiO(2) sol pillared clay, has been prepared by ion exchange reaction of the sodium ion in montmorillonite with positively charged SiO(2)-TiO(2) sol particles. From powder X-ray diffraction (XRD), the basal spacing (d(001)) of sample calcined at 400 degrees C was found to be 4.65 nm, due to the multistacking of nanosized SiO(2) and TiO(2) sol particles, which was confirmed by micropore analysis calculated from nitrogen adsorption. The BET specific surface area shows the value of 446 m(2)/g and total porosity is found to be 0.28 ml/g, and the pores are mainly composed of micropore with a size of ca. 1.1 nm. TiO(2) particles stabilized in the interlayer space of montmorillonite are found to be quantum size according to UV-vis spectroscopy. The photocatalytic properties of the SiO(2)-TiO(2) pillars were investigated in the degradation of methyl orange in water. The optimal photocatalyst amount is 55 mg/l with the reaction rate constant being 0.33 h(-1). The presence of iron ions dopants does not influence or is detrimental for the occurrence of methyl orange photodegradation. (c) 2005 Elsevier B.V. All rights reserved.