Converting Pomelo Peel into Eco-friendly and Low-Consumption Photothermic Biomass Sponge toward Multifunctioal Solar-to-Heat Conversion

Converting waste into versatile materials has been considered as an effective strategy to tackle environmental issues such as shortages in food, clean water, and energy. Conventional carbonization technology has provided an effective approach for constructing photothermal materials for interfacial evaporation or crude oil removal. However, high energy consumption, poor shape retention, and weak mechanical strength have significantly hindered the practical application of conventional carbonization technology. This work discusses how a biomass-derived sponge from discarded pomelo peel (PP) may be used to collect photothermal polypyrrole in a cost-effective way with mild reaction. The photothermic sponge which is derived from this process, can then be effectively employed to realize solar enhanced water evaporation and heavy crude oil removal. The polypyrrole-functionalized pomelo peel (FPyPP) can be attained by a mild, one-pot wet oxypolymerization method, resulting in over 95% absorption of sunlight and evaporation rates of about 1.22 kg/m2 under the sun. Furthermore, the concentrated heat on the sponge surface can efficiently reduce the viscosity of heavy crude oil and thereby lead to an effective cleanup. This study aims to provide a low-cost, low-energy-consumption, and eco-friendly approach to the acquisition of the multifunctional photothermic sponge by recycling the waste and demonstrating potential applications in tackling clean water generation and polluted water treatment.