An array structure of polydopamine/wood solar interfacial evaporator for high-efficiency water generation and desalination

Abstract

Desalination of seawater using solar energy is an effective and environmentally friendly means to solve the chronic freshwater shortage problem. However, the low conversion rate of solar energy seriously affects the application of solar energy in the field of solar thermal conversion. In this regard, we present polydopamine (PDA) loaded woods with an array structure as solar interfacial evaporators for high-efficiency solar vapor generation. It was found that the solar interfacial evaporators made of PDA/wood composites demonstrated excellent solar absorption rate (up to 93%) and the highest solar vapor generation efficiency of 97.6% under one solar illumination. It is worth mentioning that in the simulated seawater experiments, the array structure showed outstanding salt-rejected performance in 3.5% and 20% NaCl solutions, mightily thanks to the original microporous channels of the wood and the artificial millimeter cut marks. Based on the above conditions, the efficiency of PDACW-7 × 7 in simulated seawater with different salinities (3.5 and 20 wt%) under 1 kW m −2 irradiation remained at about 96.1% and 81.9%. Therefore, due to the high light absorption rate and low cost, PDA/wood composites could have good prospect in the field of solar thermal conversion and seawater desalination. • The array structure of polydopamine/wood evaporators enhances light absorption and evaporation rate. • The evaporators show excellent light absorption and photothermal conversion efficiency. • The evaporators perform favorable desalination and salt-rejecting behaviors.