Superhydrophobic Surface-Constructed Membrane Contactor with Hierarchical Lotus-Leaf-Like Interfaces for Efficient SO Capture.

An organic-inorganic polyvinylidene fluoride/polyvinylidene fluoride-silica (PVDF/PVDF-SiO) mixed matrix membrane contactor is fabricated via a facile and efficient hydrophobic modification method. The solubility parameters of the PVDF particle are precisely regulated, the PVDF particles are blended with SiO nanoparticles to form PVDF-SiO suspension, and then the suspension is introduced onto the surface of the PVDF substrate by an spin coating strategy. The PVDF particles are partly etched and incorporated to construct the adhesive PVDF-SiO core-shell layer on the PVDF substrate, which results in a more stable PVDF-SiO coating layer on the substrate. The surface structure is precisely regulated by changing the etching morphology of PVDF particles and amount of doped PVDF and SiO particles, forming an integrated porous PVDF-SiO layer and constructing hierarchical lotus-leaf-like interfaces. The resultant PVDF/PVDF-SiO membrane contactors display the relatively regular distribution of pore size with ∼420 nm and excellent hydrophobic property with a water contact angle of ∼158°, which noticeably lightens wetting phenomena of membrane contactors. The SO absorption fluxes can reach as high as 1.26 × 10 mol·m·s using 0.625 M of ethanolamine (EA) as liquid absorbent. The high stability of the SO absorption flux test indicates the excellent interface compatibility between the PVDF-SiO coating layer and the PVDF substrate. The versatile organic-inorganic layer exhibits super hydrophobic property, which prevents wetting of membrane pores. In addition, the membrane mass transfer resistance (/) and membrane phase transfer coefficient () are explored.