Easily scaled-up and portable 3D polysulfone hollow fiber membrane tree for high-efficient solar-driven clean water production

Solar-driven water evaporation based on photothermal conversion materials, such as woods, sponges, and membranes, have been proved to be promising in the field of fresh water generation. It's urgent to develop portable, versatile, and efficient photothermal materials for affordable freshwater supply. Here, a hydrophilic polysulfone hollow fiber membrane (PSF HFM) with gradient porous structure and diameter of 50 μm was prepared through one-step phase inversion method. Inspired by nature, a highly efficient 3D solar-driven steam evaporator was fabricated via chemical vapor deposition polymerization (CVDP) of hydrophobic polypyrrole (PPy) on PSF HFMs. With rational 3D structure, capillary-driven water transportation property, optical absorption as high as 95%, heat localization, photothermal conversion, a solar-driven water evaporation rate of 2.6 kg m−2·h−1, and the conversion efficiency of 173.2% could be achieved. Furthermore, the HFM tree with affluent light-harvesting, efficient thermal management, and excellent stability showed a purified water collection efficiency of 14.18 L/(m2·day) in practical application, providing a latent way to boost water purification, regeneration, and desalination. Schematic illustration of photothermal PPy-PSF HFM tree. [Display omitted] •A novel PPy-PSF HFM tree with 360 degree evaporation properties was fabricated.•The PPy-PSF HFM tree not only improved the surface area, but also decreased the heat loss adequately.•The PPy-PSF HFM tree showed a water evaporation rate of 2.6 kg m−2·h−1 under one sun illumination.•The PPy-PSF HFM tree showed a purified water collection efficiency of 14.18 L/(m2·day) in purifying simulated seawater.•The PPy-PSF HFM tree showed excellent stability during application.