Turnover polypyrrole decorated cotton fabric based solar evaporator for cost-effective and steady desalination

Interfacial solar steam production (ISSP) is an attractive technique for extracting freshwater from seawater. However, significant efforts have been focused on designing solar evaporators with delicate structures to achieve excellent evaporation rates and steady desalination performance, which result in sophisticated processes and high costs that inhibit their practical application. Here, a cost-effective turnover polypyrrole decorated cotton fabric (PPy-CF) based solar evaporator was designed by sewing two identical pieces of PPy-CF photothermal material to the top and bottom of polyethylene foam (PF). The polyester fiber pillar (PFP) inserted into the PF incorporates vertical water-transporting channels to pump water into the PPy-CF efficiently. The heat dissipation of the PPy-CF was minimized by adjusting the number of PFP. The appropriate water supplied by the PFP water transporter enables the PPy-CF-based solar evaporator to attain an excellent evaporation rate of 1.56 kg m−2 h−1 and a remarkable photothermal efficiency of 90.45% under 1-solar intensity. Notably, the sufficient water provided by the PFP water transporter allows the PPy-CF-based solar evaporator to achieve a steady desalination performance of 8 h, and the evaporation rate maintains around 1.31 kg m−2 h−1. Moreover, this solar evaporator can be self-cleaning by turning it over. Outdoor cycle experiments demonstrated that a 1 m2 PPy-CF-based solar evaporator could produce approximately 6 kg of freshwater within 10 h. Designing a 1 m2 this turnover solar evaporator costs about 1 dollar. The cost-effectiveness, simplicity in design, self-cleaning ability, and steady desalination performance make the turnover PPy-CF-based solar evaporator a promising solution to alleviate freshwater shortages.