Novel microwave-driven synthesis of hydrophilic polyvinylidene fluoride/polyacrylic acid (PVDF/PAA) membranes and decoration with nano zero-valent-iron (nZVI) for water treatment applications

A novel microwave (MW)-based method was developed for in-situ cross-linking/polymerization of polyacrylic acid (PAA) onto hydrophilic polyvinylidene fluoride (PVDF) membrane for preparation of PVDFMW catalyticmembrane system. Unlike traditional thermal techniques, the use of MW radiation provided faster PAA polymerization and synthesis of PVDFMW membranes with excellent mechanical stability and high permeability. Air cooling and the dose-wise application of MW were the most influential parameters on the quality of PAA grafting and on the physical properties of PVDFMW membranes. Detailed surface characterization of PVDFMW revealed pores of the upper surface were occupied with PAA molecules. Nano zero-valent-iron (nZVI)-decorated PVDFMW membranes (nZVI-PVDFMW ) were prepared and their catalytic activities were tested for the degradation of bisphenol A (BPA) in a cross-flow system. The nZVI-PVDFMW system demonstrated 52% +/- 0.5 of BPA removal under low permeate flux (50 L/m(2). h) in the presence of 10 mM of H2O2. The current study demonstrated MW is an advantageous technique for the preparation of composite membranes with ultra-fine morphology and improved physical properties for use in water treatment applications.

Automated summary

A novel microwave-based method was developed for in-situ cross-linking/polymerization of polyacrylic acid onto hydrophilic polyvinylidene fluoride membranes, showing faster polymerization and synthesis with excellent physical properties. Detailed surface characterization revealed pores of the upper surface were occupied with PAA molecules, and nano zero-valent-iron decorated PVDF membranes demonstrated catalytic activity for the degradation of bisphenol A. The study highlighted the advantages of microwave technique in preparing composite membranes with improved physical properties for water treatment applications.