All-in-one solar-driven evaporator for high-performance water desalination and synchronous volatile organic compound degradation

Abstract

Solar-driven evaporation is thought to be a fantastic strategy for freshwater generation, but the evaporated vapor inevitably accumulates volatile organic compounds (VOCs) in the initial wastewater, leading to secondary pollution of the condensed water. Here we demonstrate a dual-functional solar evaporator based on the graphite-N (g-N) doped biochar derived from biomass waste for simultaneous desalination and VOCs degradation. The doped g-N can activate potassium peroxomonosulfate (PMS) to produce plenty of singlet oxygen (1O2) and thus decomposing VOCs, whereas numerous micropores can capture VOCs. Taking wood biomass waste as an example, its derived g-N doped wood carbon (g-N/WC) evaporator delivers a high degradation efficiency of ∼99.91 % toward VOCs (including phenol, Bisphenol A (BPA), 4,4′-Sulfonyldiphenol (BPS), and p-Chlorophenol (4-CP)), and a great evaporation rate of 1.31 kg m−2 h−1 under 1 sun. Life cycle assessment (LCA) results demonstrate that the environmental impacts across all categories and CO2 emissions of the g-N/WC evaporator are reduced by up to 98 % and 82 %, respectively, compared with other emerging materials. The developed solar evaporator repurposes biomass waste to simultaneously solve water scarcity and waste mismanagement crises with an extremely low carbon footprint, representing a promising approach toward worldwide sustainable wastewater purification and biomass waste management.