span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB"Synthesis of ZrOsub2/sub and ZrOsub2/sub/SiOsub2/sub particles and photocatalytic degradation of methylene blue/span

摘要

span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB"SiOsub2 /subparticles (0.6 ?m dia.) have been synthesized from tetraethyl orthosilicate and then decorated with ZrOsub2 /subsynthesized from zirconium tetrabutoxide. X-ray diffraction, infrared spectra, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy have been used to characterize the ZrOsub2 /suband ZrOsub2/sub/SiOsub2/sub catalysts. The results reveal that there are Si-O-Zr bridges between SiOsub2 /suband ZrOsub2/sub particles and ZrOsub2/sub deposited on the SiOsub2/sub surface. FT-IR analysis shows Si-O-Zr bonding at 1073 cmsup-1/sup. XRD analysis shows that amorphous SiOsub2/sub and tetragonal ZrOsub2/sub particles are formed at 500 ?C. SEM and TEM analyses show that SiOsub2/sub and ZrOsub2/sub/SiOsub2/sub nanocomposite particles have a spherical morphology with diameter of 700-750 nm and a uniform particle size. Photoactivity of ZrOsub2/sub and ZrOsub2/sub/SiOsub2/sub particles has been investigated in the presence of ozone under UV light with methylene blue as a sample pollutant. Pseudo-first order kinetic model gives iR/isup2/sup values to be 0.69-0.97 and 0.79-0.93 for ZrOsub2/sub and ZrOsub2/sub/SiOsub2/sub respectively. This study proves that ozone assisted ZrOsub2/sub/SiOsub2 /subcatalyst is an effective and fast-reacting system for photocatalytic removal of organic pollutants present in wastewater./span