Scalable absorber with tuneable water supply fabricated via centrifugal spinning for highly efficient and stable solar-driven interfacial desalination

Abstract

Although realising tuneable water supply in photothermal evaporation is an effective way to boost solar-driven interfacial evaporation for water desalination, simultaneously achieving continuous water transport and appropriate water content in evaporators remains a significant challenge. To address this challenge, centrifugal spinning technology is proposed herein to fabricate a scalable, flexible and stable photothermal evaporator from a hydrophilic (polyacrylonitrile, (PAN)) and hydrophobic polymer medium (polyurethane, (PU)). Efficient water management can be realised by tuning the parameters of polymer materials to permit vapour escape and achieve salt resistance. In addition, the arched design of the evaporator allows for omnidirectional evaporation, which enhances the photothermal conversion efficiency. The scalable centrifugal spinning nonwoven membrane-based arched evaporator prepared at the optimal hydrophilic–hydrophobic polymer ratio (21 wt% PAN and 2 wt% PU) after polypyrrole modification (PPy/21PAN/2PU CSMAE) offers a highly efficient evaporation rate of 1.82 kg m−2 h−1 with photothermal efficiency of 97.33 % under 1-sun illumination and excellent salt resistance against high-salinity brine (10 wt%). Thus, the unique properties of centrifugal spinning technology enable the large-scale preparation application of multicomponent polymeric materials for realising tuneable water supply in solar-driven interfacial evaporation and desalination.