Polyvinylidene Fluoride-Based Membranes: Syntheses, Modifications, and Applications in Anaerobic Membrane Bioreactors

Owing to advantageous properties such as high mechanical strength and wear and hydrolysis resistance, polyvinylidene fluoride (PVDF)-based materials have been widely used to fabricate membranes utilizing in anaerobic membrane bioreactors (AnMBRs) for wastewater treatment. Though AnMBRs can be regarded as high-rate bioreactors, membrane fouling caused by organic, inorganic, and biological contaminants remains an inevitable challenge. In order to alleviate this issue, this review systematically summarizes modification methods including crosslinking, surface coating, and assembly for the loading of functional materials and inorganic nanoparticles onto the membrane surface. Additionally, this review indicates that modified PVDF-based membranes with enhanced conductive or antifouling properties can be effectively applied in AnMBRs, and better chemical oxygen demand (COD) removal efficiency can be achieved compared with those utilizing pristine PVDF membranes. Different from previous reviews, this review proposes technology intensification strategies utilizing pristine PVDF membranes including electrochemical AnMBR (electro-AnMBR) and anaerobic fluidized bed membrane bioreactor (AFMBR). Both of them have demonstrated enormous potential for mitigating membrane fouling relative to conventional AnMBR configurations. Spontaneously, this review underscores the critical need to integrate these intensification strategies with modified PVDF-based membranes as relative studies in this combined area. Therefore, this review provides comprehensive guidance on modification methods of PVDF membranes and technology intensification strategies utilizing modified PVDF-based membranes.