Study On PVDF Photocatalytic Membrane Capsulated By Zr Doped Ordered Mesoporous SiO₂/void/TiO₂for Enhancing Transfer

Titanium dioxide (TiO2) photocatalyst is considered to be one of the mostdevelopment potential wastewater treatment technologies for its high photccatalyticactivity, safe, nontoxicity and chemical stability. However, in the process of treatingwastewater, TiO2photocatalyst has problems about recycle and secondary pollutionfor the size of TiO2nanoparticles is too small. The barriers can be handled by coatinga SiO2shell on TiO2nanoparticles to fabricate SiO2/void/TiO2shell-core particles. Atlast the particles are doped into polymer supporters. However, the result of mass andlight transfer in the process of photocatalysis is seriously restricted by the waterpassage affected by amphipathic property and the pore diameter of SiO2shell, leadingto a low efficiency of photocatalysis. Therefore, it is important to improve the massand light transfer in the process of photocatalysis.In this study, the Zr doped into SiO2/void/TiO2shell-core particles werefabricated by the synergy effect of P123and oleic acid and cohydrolysis betweenZrOCl2·8H2O and TEOS with mesoporous pores radial distributed to TiO2particles,denoted as Zr-SVT. The mass tansfer was enhanced by the water passage produced bythe pore of Zr doped SiO2shell. This is because lattice defect of SiO2with Lewis acidsite and Br nsted acid site was formed by Zr doped into SiO2lattice. At last, Zr-SVTwas doped into polyvinylidene fluoride (PVDF) to obtain photocatalytic membrane,denoted as Zr-SVTP. Meantime, the efficiency of photocatalysis can be improved byetching under NaHCO3solution.The chemical composition and morphology of Zr-SVT were characterized bysmall angle XRD、SEM、FT-IR、TEM and BET. The results show that Zr-SVT is goodsphericity with ordered mesoporous SiO2shell and the size of Zr-SVT is about800nm. The specific surface area of etched Zr-SVT is924.7m2g-1and the pore diameteris5.5nm. Besides, the cross-sectional structure of Zr-SVTP was illustrated by SEM.The results certify that Zr-SVT was successfully doped into PVDF. Additionally, thepreparation conditions of Zr-SVT and Zr-SVTP were optimized and the factorsaffecting the photocatalytic activities of Zr-SVT and Zr-SVTP were researched bydecomposing wastewater containing oil and methyl orange solution.In addition, the mechanism of doping Zr element, mass transfer, and etching by NaHCO3solution are revealed via investigating the Zr-SVT and Zr-SVTP chemicalproperties, microstructure and preparation condition. These experiments will supply anovelty work for enhancing mass transfer and photocatalytic activity.