Role of impregnated nano-photocatalyst (SnxTi(1-x)O2) inside mesoporous silica (SBA-15) for degradation of organic pollutant (Rhodamine B) under UV light

Autor: Rajdip Bandyopadhyaya, Arup R. Bhattacharyya, Deepa C. Khandekar
Rok vydání: 2019
Předmět:
Zdroj: Journal of Environmental Chemical Engineering. 7:103433
ISSN: 2213-3437
Popis: SBA-15 of high specific surface area (507 m2/g) and pore volume (1.05 cm3/g) [due to the presence of hexagonally arranged 8.26 nm pore diameter], was synthesized by sol-gel method and impregnated with different mole ratios of Sn to Ti, in order to prepare TiO2-SBA-15, Sn0.05Ti0.95O2-SBA-15, Sn0.08Ti0.92O2-SBA-15 and SnO2-SBA-15 photocatalysts. The average SBA-15 particle diameter was 740 nm. Impregnation of photocatalyst inside the SBA-15 pores were confirmed by electron microscopy and pore-size measurement. The anatase phase of TiO2-SBA-15 shifted to an anatase-rutile phase, after Sn-doping. A decrease of impregnated catalyst size (amongst the four catalysts), from 6.7 to 6.1 nm, due to lattice strain was confirmed by X-ray diffraction. From X-ray photoelectron spectroscopy, the oxidation states for TiO2-SBA-15 and SnO2-SBA-15 were found to be Ti4+ and Sn4+, respectively. It remained unchanged after Sn-doping of catalyst too. Subsequent UV-light based photocatalytic degradation of Rhodamine B, an organic pollutant, was conducted under various pH conditions. At pH 4.5, amongst these catalysts, Sn0.05Ti0.95O2-SBA-15 shows the highest activity (pseudo-first order kinetic rate constant of 1.36 h−1). The intermediate products during degradation were identified by HR-LC/MS and GC/MS. The temporal changes in Rhodamine B concentration both from UV-Vis absorbance and HR-LC/MS measurements were consistent too.
Databáze: OpenAIRE