High-absorption recyclable photothermal membranes used in a bionic system for high-efficiency solar desalination via enhanced localized heating

Abstract

Desalination utilizing solar energy is an effective way to mitigate the crisis of water shortage, but its large-scale application in production has been largely limited by the low evaporation efficiency. Here, we report a plate thermal reduction (PTR) method for rapid preparation of plasmonic-active filter paper (PP) as the photothermal material with broadband solar absorption over 92%. By imitating the spontaneous water circulation mechanism of plants, we designed a high-efficiency bionic solar evaporation and desalination system. Air with excellent low thermal conductivity was used as the thermal insulation material. Because of the enhanced localized heating effect, the system features a high solar evaporation efficiency of up to 89% under 10 kW m⁻². Furthermore, under natural sunlight, the bionic system has a drinkable freshwater production rate of 0.97 kg m⁻² h⁻¹ under about 0.9 kW m⁻² with the highest evaporation efficiency of 79% for one day. With simple material preparation and efficient and stable performance, the bionic system is ideal for large-scale production to tackle energy, water resource and environmental issues.