Aluminum-based solar seawater desalination interface evaporator processed by picosecond laser combined with fire treatment

Abstract

Solar interfacial evaporator is one of the most attractive and continuous approaches to solve the global freshwater shortage issues, especially in terms of desalinating seawater and purifying industrial wastewater. Since the interfacial evaporator prepared by traditional methods is difficult to produce fresh water stably for a long time, it is difficult to be widely used. Here, we propose an aluminum (Al) -based solar interfacial evaporator prepared by picosecond laser ablation combined with fire treatment (LTF) method. The prepared surface exhibits superhydrophilicity and ultra-high light absorption rate (99 %). The average evaporation rate under one sun (1 KW·m⁻²) exposure can reach 3.5 kg·m⁻²·h⁻¹, with the solar thermal conversion efficiency of 80.51 %. Moreover, during the 20-day successive desalination, the evaporation capability of the LTF processed Al (LTF-AL) surface remains stable. Even when the performance is reduced, the performance can be restored to its previous state with a simple fire treatment. Furthermore, the prepared surface can be used to purify contaminated water. After desalination, the ion concentration of seawater (Bohai Sea) is much lower than the ion concentration limit set by the WHO for drinkable water. The laser ablation combined with fire treatment provides a fast and simple method for high efficiency solar desalination in the real world.