Development of a Polyvinylidene fluoride–based membrane incorporating magnetic iron–nickel alloy for vacuum membrane distillation desalination

Abstract Novel mixed a starfish-like shaped magnetic iron-nickel alloy with Polyvinylidene fluoride (PVDF) matrix membranes were developed for water desalination using vacuum membrane distillation (VMD). This study highlights the alloy’s unique morphology that coated by the hydrophobic polymer, which enhances water vapor transport through innovative pore formation and its permanent magnetic properties, distinguishing it from existing research. The membranes were characterized using scanning electron microscopy (SEM), Energy Dispersive X‑ray (EDX) analysis and mapping, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), and Thermal Gravimetric Analysis (TGA), along with measurements of Liquid Entry Pressure (LEP), static water contact angle, tensile strength, thickness, roughness, porosity, pore size and pore size distribution. Performance tests in a VMD system showed that the iron–nickel alloy increased membrane productivity by 47% compared to pristine PVDF membranes. The 0.2 wt% alloy with 14% PVDF achieved the highest porosity (74.32%) and flux (29.1 kg/m²·h), balancing surface roughness and structural integrity. In contrast, higher polymer content (18 wt% PVDF) negatively impacted porosity and led to performance trade-offs. Thus, this study emphasizes the critical interplay between porosity, roughness, thickness, and the magnetic properties of the alloy in optimizing membrane performance for VMD applications.