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

In membrane contactors, maintaining a high SO2 absorption flux and an excellent wetting resistance are crucial for hazardous gas removal. In this study, we adopted an electrospinning strategy to fabricate highly robust super hydrophobic dual-layer Elec-PVDF/SiO2 composite membrane contactors used for flue gas desulfurization. The composite membrane contactor consisted of a durable and ultrathin three-dimensional (3D) superhydrophobic surface and a porous supporting layer, where the formulation was 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 were conducted to explore the physical and chemical structure. The SiO2nanoparticles were uniformly loaded in ElecPVDF/SiO2 composite membrane contactor, and constructed micro-nano dual-coarse lotus-leaf-like morphology, which noticeably elevated surface roughness (Ra). The SiO2 nanoparticles also functioned as hydrophobic modifiers, which boosted the WAC up to 155 degrees. The SO2 absorption fluxes and SO2 removal efficiencies were investigated. In particular, the membrane contactor doped with 20 wt% SiO2 nanoparticles significantly elevated the stability of desulfurization performance. Besides, the membrane mass transfer coefficient (Km) and corresponding membrane mass transfer resistance (H/Km) were explored.