Preparation and characteristic of graphene oxide-acylase/poly(vinylidene fluoride) composite membrane

A new type of graphene oxide-acylase (GO-acylase) nanoparticles was produced via an electrostatic force. The GO and GO-acylase were added to the poly(vinylidene fluoride) (PVDF) membrane casting solution respectively, and the GO/PVDF and GO-acylase/PVDF composite membranes were prepared through phase inversion by the immersion precipitation technique. The results show that the surface roughness of GO-acylase/PVDF membrane is very smooth (R_a=8.21 nm), and the contact angles of GO/PVDF and GO-acylase/PVDF membranes are relatively lower (73.72° and 71.31°), which indicates that the hydrophilicity of composite membranes are better than that of pristine PVDF membrane. The addition of GO enhances the transformation process between solute and insoluble, which results in the highest pure water flux (69.0 L/(m²h)) of GO/PVDF membrane. The biological activity of GO-acylase/PVDF membrane can be maintained for about 4 weeks, which indicates that the new GO-acylase/PVDF membrane is prepared successfully, and provides a new way to mitigate the bio-fouling of membrane.