Chemically graft aminated GO onto dehydro-fluorinated PVDF for preparation of homogenous DF-PVDF/GO-NH2 ultrafiltration membrane with high permeability and antifouling performance

Blending of hydrophilic nanoparticles into the PVDF ultrafiltration membrane has been proved to be an effective and simple way to improve the hydrophilicity and the anti-fouling performance. However, due to the heterogeneous nature, aggregation or leakage of the hydrophilic nanoparticles usually happened at higher concentration which would further go against for improving the filtration performance. Here, aminated graphene oxide (GO-NH2) and dehydro-fluorination polyvinylidene fluoride (DF-PVDF) were synthesized, and GO-NH2 was chemically grafted on DF-PVDF via Michael addition reaction. The resultant DF-PVDF/GO-NH2 membrane was obtained, and the structure, hydrophilicity, and the antifouling performance of DF-PVDF/GO-NH2 membrane are systematically investigated. As a result, the GO-NH2 grafted membranes (Mg membranes) exhibited uniform and smooth surfaces with numerous visible pores and higher porosity compared to GO co-blending membranes (Mb membranes) and the original PVDF membrane. Besides, the Mg membranes possessed lower water contact angle (48°± 1.0°), higher water flux (355 L/m2 h) and better flux recovery ratio (up to 88%), showing better hydrophilicity and anti-fouling performance together with better mechanical properties. Static adsorption experiment also indicated the better anti-fouling performance of Mg membranes due to the uniformly dispersion of hydrophilic GO and the strong electrostatic repulsion between negatively charged GO and BSA.