Surface modified by green synthetic of Cu-MOF-74 to improve the anti-biofouling properties of PVDF membranes

Mitigation of membrane fouling is an important problem to be solved in the application of membrane technology. In this research, we synthesised a kind of Cu-MOF-74 by a facile and environmentally friendly method at room temperature. This kind of Cu-MOF-74 was firstly and successfully coated on poly (vinylidene fluoride) (PVDF) membranes for improving their anti-biofouling performance. The experimental results show that Cu-MOF-74 increases the hydrophilicity and roughness of the PVDF membrane surface, and the antibacterial efficiency of the modified membrane was as high as 97.7% at 4 h. Moreover, we found that the Cu-MOF-74 could sustainably release Cu2+ for one week, the maximum Cu2+ release concentration of PVDF membrane coated by 0.025 g Cu-MOF-74 reached 0.42 mg/L, and the generation of Cu2+ played a significant role in suppressing E. coli. In the meantime, this kind of Cu-MOF-74 can release OH, which will lead to the accumulation of reactive oxygen species (ROS) in bacterial cells. The ·OH can oxidise and destroy bacterial cells, which will be in favour of enhancing the anti-biofouling performance. This novel PVDF membrane surface modified by green synthetic Cu-MOF-74 has a strong antibacterial property and high application potential for water treatment.