In-situ pyrrole polymerized wood sponge for efficient solar interfacial evaporation and desalination

Solar-driven interfacial evaporation (SIE) can effectively use abundant solar energy and seawater to supplement freshwater resources, with wood being an ideal matrix. Thus, a wood-based device was synthesized by in-situ polymerization of pyrrole (Py) monomers on a wood sponge (WS) with lignin and hemicellulose removed (named PPy-WS). The porosity of the WS significantly increased following the removal of lignin and hemicellulose, while PPy loading enhanced the ability of PPy-WS to absorb light (92 %). Under 1.0 sun (100 kW cm- 2 ), the water in the PPy-WS-based SIE system evaporated at a rate of 3.14 kg m- 2 h-1, and the energy utilization reached 102.6 %. Compared with that in pure water, the rate of evaporation in 3.5 wt% brine was 3.05 kg m- 2 h-1, ranging 6.64-7.74 kg m- 2 h- 1 under 2.5 m s-1 of directional flow during the 7-day experiment. These results indicate that PPy-WS has good self-desalination ability and long-term stability. In the outdoor experiment, the maximum evaporation rate of PPy-WS was 9.67 kg m- 2 h- 1 at the 13:00 time point (with 79.4 mW cm- 2 luminous flux and 1.5 m s- 1 convection flow rate). Thus, the PPy-WS evaporator is environmentally friendly, low-cost, and has a high evaporation rate.