Capillary-force-driven solar steam generators printed by multi jet fusion

Abstract

Solar steam generation has great application prospect in seawater desalination to obtain clean water. However, it is still a challenge to realize a high efficiency, high water quality, low cost and sustainable seawater desalination method. Three-dimensional (3D) structural design of solar steam generators (SSGs) is conducive to promote the water evaporation efficiency for effective seawater desalination. In this work, porous SSGs with special surface structures that exhibited excellent photothermal performance and salt self-cleaning properties are built by Multi Jet Fusion, a powder-based 3D printing technique. Sodium carbonate is introduced as a recyclable porogen for MJF printing. The MJF-printed porous polymeric SSGs have lightweight characteristics, and the interconnected pores promote water flow via capillary action. It is observed that SSGs with tree-like surface structures can suppress heat dissipation and increase photothermal conversion efficiency, resulting in high water evaporation rates. The seawater desalination rate per unit area was 12 g m-2 h-1, with the concentrations of various ions in the purified water meeting the requirements for direct drinking. In addition, the MJF-printed SSGs can self-clean and remove accumulated salts on their surfaces, and the water evaporation rate remains stable over a long period of time. Hence, the proposed porous SSGs with tree-like surface structures are promising for efficient and sustainable seawater desalination.