Photothermal Interfacial Evaporation Characteristics of PVA/SA–CNT–Borax Hydrogel

The desalination of seawater has demonstrated significant potential to use solar-driven interfacial evaporation technologies due to its sustainability, outstanding productivity, and kindness to the environment. In this paper, a hydrogel interfacial evaporator was produced, with PVA and SA as the base materials. The addition of carbon nanotubes (CNTs) was used to enhance the photothermal conversion efficiency, and the cross-linking procedure was carried out employing sodium tetraborate decahydrate (borax). The experimental study researched how evaporation efficiency was affected by varying sodium chloride concentrations, light intensity, and borax cross-linking levels. The study confirmed that the hydrogel cross-linked with 4% borax exhibits the best efficiency of evaporation, reaching a 2.709 kg/m 2 · h evaporation rate and 98% evaporation efficiency. Moreover, it demonstrates excellent salt tolerance and stability during the process. This study effectively created an inexpensive, eco-friendly, nontoxic, and easy-to-fabricate hydrogel evaporator, which provides a very important reference value for the development of the novel kind of solar thermal evaporator.