Solar‐driven brine desalination and concentration by controlled salt excretion

Abstract Desalination technology provides one promising solution to the global water shortage problem yet brings about a new challenge of managing massive waste brines. Recently, interfacial solar steam generation technology has gained increasing attention for brine treatment due to its high energy‐conversion efficiency and applicability to hypersaline brines. However, it is challenging to maintain high performance because of salt fouling problem. Herein, this study presents a novel salt excretion approach to maintaining the evaporation efficiency of interfacial solar steam systems for improved long‐term stability in brine desalination. By creating a directional flow, accumulated salts are excreted via discharging the concentrated brine. This approach is effective and applicable for brines with a broad range of concentration owing to its tuneable concentrating performance. With the capability of continuously producing clean water and near‐saturation brine, this work advances solar steam technologies toward practical applications, such as brine concentration and resource recovery. image