ZrO2 solid superacid porous shell/void/TiO2 core particles (ZVT)/polyvinylidene fluoride (PVDF) composite membranes with anti-fouling performance for sewage treatment

• ZrO2 solid superacid porous shell/void/TiO2 core particles (ZVT) and ZVT/PVDF composite membranes are successfully prepared.
• Micro reaction locations (MRLs) are formed inside channels and surface of PVDF membranes.
• ZVT can interact with PVDF chains by hydrogen bonds.
• ZVT/PVDF composite membranes have good anti-fouling, anti-compaction and hydrophilic properties.

To enhance the capabilities of anti-fouling, anti-compaction and hydrophilicity of PVDF membranes, ZrO2 solid superacid porous shell/void/TiO2 core particles (ZVT) were firstly prepared and then doped them to PVDF to prepare a novel composite membrane (ZVT/PVDF composite membrane) through a phase inversion process. ZVT and ZVT/PVDF composite membranes were characterized through scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) and Fourier transform infrared (FT-IR), respectively. The results indicate that ZVT with the diameter of around 500 nm are uniformly dispersed in PVDF membranes, the pore size of ZrO2 shell is about 3 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 results of anti-compaction, contact angle and tensile strength measurements show that ZVT/PVDF composite membranes have anti-compaction, hydrophilicity properties and mechanical strength. Ultrafiltration experiment indicates ZVT/PVDF composite membranes show fine oil retention property and its oil retention ratio reaches 93.82%. And chemical cleaning and photocatalytic activity tests indicate that ZVT/PVDF composite membranes have anti-fouling property. Therefore, ZVT/PVDF composite membranes with anti-fouling, anti-compaction and hydrophilic properties are desirable for sewage treatment.