Integrated solar seawater desalination and power generation via plasmonic sawdust-derived biochar: Waste to wealth

Abstract

Solar steam generation (SSG) provides a promising technique to remedy the worldwide water and energy crisis with minimum environmental impact. Herein, we successfully recycled the wood wastes (sawdust) to construct biochar as an evaporator via the pyrolysis technique which was performed at low temperature to keep the abundant aligned microchannels across the wood structure, increasing water transportation to the surface. Bimetallic plasmonic nanoshells dopped the biochar to enhance SG via the multiple nucleation sites, benefiting from their excellent light absorption. Besides, a thermoelectric (TE) generator can be integrated with the Ag-Cu/ SDB@PVA membrane for concurrent steam and electricity generation. As a result, the evaporator achieves a simultaneous evaporation rate of 1.49 kg m−2 h−1 (90.4% efficiency) and a power density of 34.7 mW/m2 under 1 sun illumination. The highest potential and power density of induced electricity can be achieved under blue LED illumination. Thanks to the different interactions of salt ions with the functional groups of biochar, our evaporator shows extraordinarily salt-resistant performance under 1 sun illumination. Based on its excellent energy-conversion efficiency, facile and cost-effective fabrication process, salt-resistance, and durability, our evaporator may be a promising generator for drinkable water and electricity on a large scale.