Designing Anti-Fouling PVDF Membranes by Synergizing Cu2+ and Sodium Lignosulphonate Additives

Membrane separation technology with high separation efficiency and low energy consumption are one of the keys to tackle the water-energy crisis. However, membrane fouling can reduce membrane life and performance, limiting its application. In this work, hydrophilic modifier sodium lignosulphonate (SLS) and antibacterial agent CuCl2 were adopted as additives to modify PVDF membranes. The addition of SLS can optimize the structure of PVDF membranes and increase hydrophilicity, enhancing separation and anti-fouling performance. Moreover, the SLS can fix Cu2+ effectively onto the membrane for improved antibacterial performance, as the leakage of Cu2+ is reduced greatly, compared to Cu-PVDF membranes without SLS. The simulation based on density functional theory proved that the binding energy of SLS and Cu2+ is 2.7 times of that of PVDF and Cu2+. Finally, the prepared anti-fouling Cu-SLS/PVDF membrane was applied in the separation of simulated Escherichia coli fermentation broth, exhibiting long-term antibacterial and anti-fouling property. This work provides a new idea for the preparation of long-term anti-fouling and antibacterial membrane, and has good potential in the recovery of fermentation broth.