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. (Figure presented.).