Preparation and Characterization of Novel Polyethersulfone Hybrid Ultrafiltration Membranes Bending with Modified Halloysite Nanotubes Loaded with Silver Nanoparticles

In this study, poly(4-vinylpyridine) (P4VP) was first grafted onto the surface of halloysite nanotubes (HNTs) via in situ polymerization, and then, silver ions were immobilized on P4VP via complex reaction. Finally, silver ions were reduced to silver nanoparticles (Ag NPs). Polyethersulfone (PES) ultrafiltration membranes bending with modified HNTs loaded with Ag NPs were prepared via phase inversion. FT-IR spectra and TGA results showed that HNTs were modified successfully. The contact angle data indicated that the hydrophilicity of the membranes was enhanced by the addition of modified HNTs. The permeation properties of the hybrid membranes were significantly superior to the pure PES membrane, especially when the modified HNTs content was 3%; the pure water flux of the membrane reached the maximum at 396.5 L.m(-2).h(-1), which was about 251.5% higher than that of the pure PES membrane, and the rejection was slightly affected by the addition of the modified HNTs. The microstructure of the membranes was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that the structure of membrane was not obviously affected by addition of the modified HNTs. Antibacterial activity of the hybrid membrane was evaluated with the viable cell count method using antibacterial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial rates of the hybrid membranes against E. coli and S. aureus were about 99.9% and 99.8%, respectively.