Electrospinning in membrane contactor: manufacturing Elec-PVDF/SiO2 superhydrophobic surface for efficient flue gas desulphurization applications

Abstract In membrane contactors, maintaining a high SO2 absorption flux and an excellent wetting resistance are crucial for hazardous gas removal. In this study, we adopt an electrospinning strategy to fabricate highly robust superhydrophobic dual-layer Elec-PVDF/SiO2 composite membrane contactors used for flue gas desulphurization. The composite membrane contactor consists of a durable and ultrathin three-dimensional (3D) superhydrophobic surface and a porous supporting layer, where the formulation is optimized by regulating the PVDF concentration, solvent ratio and SiO2 particles content in electrospinning solution. The scanning electronic microscopy (SEM), EDS-mapping, water contact angle (WCA) and surface roughness of as-prepared Elec-PVDF/SiO2 composite membrane contactors are conducted to explore the physical and chemical structure. The SiO2 nanoparticles are uniformly loaded in Elec-PVDF/SiO2 composite membrane contactor, and construct micro-nano dual-coarse lotus-leaf-like morphology, which noticeably elevates surface roughness (Ra). The SiO2 nanoparticles also function as hydrophobic modifiers, which boost the WAC up to 155 o. The SO2 absorption fluxes and SO2 removal efficiencies are investigated. In particular, the membrane contactor doped with 20 wt% SiO2 nanoparticles significantly elevates the stability of desulfurization performance. Besides, the membrane mass transfer coefficient (Km) and corresponding membrane mass transfer resistance (H/Km) are explored.