Turning Trash into Treasure: Pencil Waste–Derived Materials for Solar‐Powered Water Evaporation

Abstract

Solar steam generation is regarded as one of the most attractive technologies to relieve the stress of freshwater storage. Low cost and scalable production of solar evaporators is a critical issue to be considered for practical applications. Herein, the recycling utilization of pencil wastes is proposed by a facile method. A self‐floating solar evaporator made of carbonized pencil wastes can achieve an evaporation rate of 1.2 kg m−2 h−1 and a light‐to‐vapor energy conversion efficiency of 82.2% under 1.0 sun. Meanwhile, the evaporator exhibits a self‐desalting property overnight due to its superior hydrophilicity. Furthermore, the evaporator manifests significantly effective solar evaporation performance in brine, organic dye solutions, as well as other harsh conditions. Considering the wide range of raw sources, low cost, scalable preparation, and effective solar evaporation performance, the all wood waste–based solar steam generator provides an inspiration for the recycling utilization of wood wastes and the promising development of environmentally friendly biomass‐based solar evaporators.