Piezocatalytic property of PVDF/Graphene self-assembling piezoelectric membrane for environmental remediation

In recent years, industrial pollution has become an inescapable global issue. The catalytic degradation processes driven by environmental sources, such as photocatalysis and piezocatalysis, are among the effective solutions. However, the difficulty in recycling catalysts leads to secondary pollution, limiting their practical application. This study develops a graphene-based self-assembled piezocatalytic membrane. Through Non-solvent Induced Phase Separation (NIPS), polyvinylidene fluoride (PVDF)/graphene asymmetrical membrane was prepared. The addition of graphene induced the self-assembly of PVDF crystalline phases into piezoelectric β phase. The membrane generates the ROS species to degrade the pollutant by the screen charge from material surface under a piezoelectric field. The optimal membrane exhibits the highest Vpp value of 4.26 V, and significant degradation efficiency of 80.2 % and 85.6 % for methylene blue (MnB) and crystal violet (CV), respectively, which are positively charged dyes. Meanwhile, the degradation efficiency within 2 h reached 73.8 % for negatively charged methyl orange (MO) and 96.1 % for toxic rhodamine B (RhB). This study successfully developed a crystalline self-assembled piezocatalytic membrane, providing fundamental insights into its piezoelectric response and various pollutant degradation. It introduces new directions and possibilities for the future development of membrane-based piezocatalysis.