Sustainable Lignocellulose-Based Sponge Coated with Polypyrrole for Efficient Solar Steam Generation

Solar evaporative desalination technology is one of the most promising technologies to alleviate freshwater shortages, but the preparation of an inexpensive and sustainable 3D substrate remains a challenge. Lignocellulosic sponge (LS) is a commercial product that is widely available, clean, renewable, degradable, inexpensive, and porous. In this work, LS was found to be a good substrate for photothermal evaporation. LS has good compatibility with polypyrrole (PPy), which has excellent photothermal conversion performance. A simple and effective photothermal conversion evaporator (PPy-LS) was obtained by in situ polymerization of pyrrole on the surface of LS by chemical oxidation. The as-prepared PPy-LS exhibited good light absorption and thermal management capabilities, possessing an evaporation rate of 1.85 kg m–2 h–1 and an evaporation efficiency of 88.65% at 1 sunlight. PPy-LS also had excellent mechanical properties, superhydrophilicity, and water absorption. Combined with its porous network structure, PPy-LS exhibited good salt tolerance in 10 wt % NaCl solution and excellent thermal management capability. The PPy-LS solar evaporation device has the advantages of a simple preparation method, good durability, and sustainability, which provides an important direction for solar interface evaporation.