Novel nanofluid based efficient solar vaporization systems with applications in desalination and wastewater treatment

The current work proposes a new strategy to improve solar evaporation efficiency and explore the real applications of volumetric solar evaporation device in desalination and wastewater treatment. Nanofluid based volumetric solar evaporation system is efficient to enhance the absorbance of solar irradiation. However, the solar evaporation efficiencies are relatively low. There is a need to investigate the fundamentals of the limitation and find a new strategy to improve the solar evaporation efficiency. In this paper, a novel device containing tungsten carbide nanofluids as work fluids is designed for the first time to reduce heat loss towards the bulk water, improve the stability of nanofluids, and avoid contamination of nanoparticles. The results show that tungsten carbide nanofluids of 0.3 wt% can harvest 99% of the incident solar energy within 1 cm penetration distance. The photothermal conversion efficiency is 97.7%. The novel device gives an evaporation rate of 1.235 kg m(-2) h(-1) and reached solar evaporation efficiency of 74.9% under 1-sun irradiation. The applications in desalination and wastewater treatment show that the ion rejection rate of seawater is higher than 99.99%, and the content of heavy metal ion is significantly lower than that in the World Health Organization drinking-water standard. (C)& nbsp;2022 Elsevier Ltd. All rights reserved.