In situ photo-thermal conversion nanofiber membrane consisting of hydrophilic PAN layer and hydrophobic PVDF-ATO layer for improving solar-thermal membrane distillation

Solar thermal membrane distillation is a promising technology for low-cost desalination and water purification. A novel photo-thermal conversion membrane composited by polyacrylonitrile (PAN) nanofiber layer and polyvinylidene fluoride (PVDF) with antimony tin oxide (ATO) as solar-thermal nanoparticles (PVDF-ATO/PAN nanofiber membrane) was fabricated by sequent electrospinning techniques. The dual-layer membrane with hydrophilic PAN and hydrophobic PVDF-ATO was examined by microscopic evaluation and contact angle measurement. In situ temperature increase on membrane superficial layer (PVDF-ATO) driven by solar light illumination was confirmed by thermal imaging system. PAN layer provides water transport channels for facilitating water flow of highly efficient membrane distillation and avoids the salting assembly during the vigorous evaporation. With the help of hydrophilic PAN layer, our PVDF-ATO/PAN nanofiber membrane can fulfill highly effective localized heating transfer with an evaporate rate of 0.93 kg m−2 h−1, showing great potential for low-cost water desalination and scalable water purification. [Display omitted] •A solar-thermal PVDF-ATO/PAN fiber membrane was yielded by sequent electrospinning.•PAN and PVDF-ATO contribute moisture transport and localized heating, respectively.•The resulting membrane has an appreciable evaporation rate of 0.93 kg m−2 h−1.•It exhibits robust heat localization, excellent durability, and good anti-fouling.•A desired solution to low-cost desalination & scalable water purification was done.