Cellulose nanofibril/polyvinyl alcohol hydrogel achieves efficient desalination of seawater and power generation...

The solar evaporation system with both desalination and power generation functions provides an important solution to the problems of water shortage and energy crisis. However, during the long-term operation of the evaporator, there is still a problem of surface salt accumulation. This work uses cellulose nanofibrils (CNFs) and polyvinyl alcohol (PVA) as the base materials and utilizes the -SO₃^- generated by the ionization of polystyrene sulfonic acid (PSS) to construct the Donnan effect, achieving both efficient salt tolerance and hydroelectric power generation simultaneously. Its evaporation rate can reach 1.92 kg m^-2 h^-1 under 1 sun, with an efficiency of up to 94.1%; in a 10 wt% salt water environment, after 8 h of continuous illumination, there is no obvious salt crystallization or deposition on the surface of the evaporator. At the same time, the potential difference formed by the directional enrichment of H⁺ produced by the ionization in the hydrogel enables the PCP hydrogel to continuously output 0.36 V. This provides a new idea for the preparation of multifunctional evaporators with high salt tolerance and power generation capabilities.