Surface modification of PVDF membrane by CNC/Cu-MOF-74 for enhancing antifouling property

• Surface of PVDF membranes was modified by CNC/Cu-MOF-74 composite. • The antifouling mechanism is related to hydrophilicity and electrostatic repulsion. • Efficiently antibacterial performance (96.3% at 4 h) is attributed to Cu 2+ and •OH. Membrane fouling is one of the main impediments that limit the wide application of Polyvinylidene fluoride (PVDF) membrane. In this study, for the first time, we incorporated the cellulose nanocrystal (CNCs) onto Cu-MOF-74 by physical stirring and then coated the composites on the PVDF membrane to ameliorate the antifouling performance. The PVDF membrane with the addition of CNC/Cu-MOF-74 composite showed enhanced hydrophilicity compared with the pristine membrane, which significantly promoted the permeability and antifouling performance. The Bovine serum albumin (BSA) multiple-cycle antifouling results revealed that the flux recovery ratio (FRR) value (76.9%) was much higher than that of the pristine membrane (60.8%). The enhancement of recovery flux was correlated with the increased electrostatic repulsion and hydrophilicity of the modified membrane according to the contact angle test and Zeta-potential measurement. Meanwhile, the CNC/Cu-MOF-74 modified membrane showed improved antibacterial efficiency (96.3% at 4 h) due to the predominant antibacterial efficacy of Cu-MOF-74. The efficiently antibacterial achievement of modified membrane was attributed to the release of Cu 2+ and the generation of •OH. This study proposed a novel modified membrane with excellent antifouling properties and provided new insights into the fabrication of antifouling membranes with outstanding performance.