High-flux blend PVDF membrane with enhanced resistance to organic solvents and high-temperature for efficient wastewater treatment

Abstract

The poor thermal stability of polyvinylidene fluoride (PVDF) membranes and their tendency to swell in organic solvents limit their widespread application in the field of membrane technology. In this study, the fluorinated polyimide (FPI), P(6FDA-BAPOFP), was investigated for the first time as a modifier for the PVDF membrane to enhance its stability at high temperatures and in organic solvents. By leveraging the inherent affinity between the C-F bond in FPI and PVDF, the compatibility of the physical blending has been significantly improved. The optimal addition of 2.5 % FPI led to a 2.0-fold increase in flux while preserving rejection. The introduction of FPI into the membrane effectively delayed the thermal weight loss, demonstrating stable performance in 90 °C water. In particular, after an operational period of up to 12 days, the modified membrane exhibited > 80 % Congo Red rejection and relative stable permeance (85 L·m⁻²·h⁻¹·bar⁻¹). This high-flux polymer membrane contributes to energy conservation and emissions reduction in industrial production.