Engineering of 0D/1D architectures in 3D networks over CDs/PPy-CPP biomass foam with high efficiency on seawater evaporation

Converting waste biomass into solar evaporator foam has been recognized as an effective strategy for waste recycling and solving the problem of water shortage, but problems of salt deposition and mechanical stability seriously hinder their practical application. Herein, this work proposes a sustainable and high mechanical strength biomass foam (CDs/PPy-CPP) evaporator with zero-dimensional/one-dimensional (0D/1D) hierarchical structure by hydrophilic carbon dots (CDs) and tubular polypyrrole (PPy) are seamlessly integrated into the outer surface of the three-dimensional (3D) carbonized pomelo peel (CPP) biomass foam. The evaporator achieved a high-efficient evaporation rate of up to 2.46 kg m−2 h−1 in 3.5 wt% NaCl solution at 1 sun irradiation, and similarly exhibited outstanding salient evaporation efficiency and resistance to salt deposition in 25 wt% NaCl solution, as well as prominent swage purification ability. Excellent photothermal conversion efficiency is demonstrated attributed to the 0D/1D structure in 3D networks of the CDs/PPy-CPP evaporator, as well as superior mechanical and water transport properties based on the multilayer mesh structure and microscopic water transport pores. The research intends to offer a low-cost, energy-efficient, and environmentally friendly approach to obtain multifunctional photothermal biomass foams and demonstrate the potential applications in seawater desalinization and swage purification.