Maneuvering the ordered mesoporosity of electrospun silica nanofibers for water harvesting

Abstract

Adsorption-based water harvesting with nanoporous materials has attracted intense attention as a break-through potential for potable water. Herein, the electrospinning technique is facilely employed to prepare ordered mesoporous silica nanofibers (SNFs) as water sorbent based on the relative humidity (RH) regulated during the electrospinning process. A comparative study of SNFs electrospun at a high RH (H-SNF) and low RH (L-SNF) shows that H-SNF features a well-ordered pore arrangement of the silica layer with transmission electron microscopy (TEM) and X-ray diffraction (XRD) patterns. Additionally, H-SNF exhibits faster water vapor adsorption-desorption because of the densely formed adsorption sites in which the pore arrangement was influenced by the surrounding water molecules during fiber formation. The mechanism responsible for the pore arrangement in the formation of SNFs describes how humidity affects the micellar assembly of nanostructured porous fibers. H-SNF possesses two times greater water uptake capacity than commercial silica gel and maintain stable and high water vapor adsorption behavior even after five cycles, indicating that the surface pores in the fibrous silica feature significantly high accessibility and connectivity.