Inorganic nanoparticles-modified polyvinyl chloride separation membrane and enhanced anti-fouling performance

Abstract

Porous nanomaterials are important additives in the preparation of high-performance separation membranes. To prepare two nanocomposites, mesoporous silicon dioxide (MCM-41) as a carrier and zinc acetate as a zinc source, Zinc oxide-loaded mesoporous silicon dioxide (ZPP-MCM) was prepared by using polydopamine (PDA) and Polyethylenimine (PEI) as water-soluble ligands, and zinc oxide-loaded mesoporous silicon dioxide (εZI-MCM) were prepared by using iminodiacetic acid (IDA) as water-soluble ligands and coated with ε-poly-l-lysine HCl. The two nanocomposites were blended into polyvinyl chloride (PVC) membranes as modifiers. The results show that the overall porosity of the composite membrane is increased. However, the surface roughness of the composite membrane is decreased with narrow pore size distribution, which was favourable for selective filtration. εZI-MCM nanoparticles can be evenly distributed on the film due to their excellent dispersion, which solves the problem of uneven distribution of nanoparticles on the film, and the surface of the prepared composite film is relatively flat. In addition, introducing the nanoparticles significantly improves the surface hydrophilicity and water flux of the composite membrane. In the experiments of pure water flux and bovine serum albumin (SBA) flux, the flat film with nanoparticles shows higher flux than pure PVC films. The addition of nano-composites further improves the anti-fouling performance and flux recovery ratio of the modified PVC membrane, and the recovery ratio of flux was more than 90%. This work exhibits that Porous nanomaterials have successfully modified the hydrophobic PVC membrane, affording good anti-fouling performance.