Enhanced solar-driven steam generation and water purification using 3D arch solar evaporators

Abstract

Steam generation strategy through solar-driven evaporators has now been widely recognized as one of the effective means to relieve the global fresh water crisis. Reducing heat loss has shown to be an effective way to improve the evaporation efficiency which has been overlooked in three-dimensional (3D) evaporators in the past. Herein, a superhydrophilic photothermal fabric was developed by the layer-by-layer assembly of carbon nanotubes followed by dip-coating with polyvinyl alcohol. The as-obtained photothermal fabric was designed as a 3D arch solar evaporator (ASE). The arch structure allowed the photothermal fabric to achieve double-sided water evaporation and a well-balanced saline water supply by controlling the height of the ASE. The ASE effectively captured the incident sunlight and demonstrated extraordinary thermal management performance, resulting in a saline water evaporation flux of 1.015–3.400 kg m−2 h−1 under 1 sun irradiation for 6 h. In addition, the proposed ASE exhibited excellent water purification for high salinity saline water, colored wastewater, and heavy metal wastewater. This work provides new insights into emerging solar steam generation systems by regulating the saline water supply balance.