Preparation of porous ZrO2 solid superacid shell/void/TiO2 core particles and effect of doping them on PVDF membranes properties

•ZVT nanoparticles with porous ZrO2 solid superacid shell/void/TiO2 core structure.•ZVT/PVDF composite membrane formed by ZVT and PVDF together.•The micro reaction locations are formed inside channels and surface of membranes.•ZVT/PVDF composite membranes perform attractive properties.

To further enhance hydrophilic and anti-fouling properties of PVDF membrane, porous ZrO2 solid superacid shell/void/TiO2 core particles (ZVT) forming micro reaction locations (MRLs) inside channels and surface of membranes were firstly prepared and then doped to PVDF to form ZVT/PVDF composite membrane. The optimum synthesis conditions of ZVT were studied and determined; the ZVT and ZVT/PVDF composite membranes were characterized by the scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR), Brunauer–Emmett–Teller (BET) and contact angle of water, respectively. Results show that the diameter of ZVT prepared under the optimum synthesis conditions is 500 nm, the thickness of ZrO2 shell is 50 nm, a solid superacid ZrO2 shell on the TiO2 core is formed due to a stretching vibration peak of SO double bond at 1460 cm−1 in FT-IR spectra. The contact angle is declined from 67.4° to 33.9° and oil retention ratio reaches 93.82% of ZVT/PVDF composite membranes, which perform the attractive hydrophilic and anti-fouling properties of ZVT/PVDF composite membranes. Therefore, ZVT are desirable as suitable fillers of polymer membranes.

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