The multi-functional solar interfacial evaporators based on almond shells

Solar evaporation technology holds profound significance as a sustainable and innovative solution to global freshwater scarcity, energy sustainability, and environmental remediation. This work presents a high-performance solar evaporator (PDAS) developed by functionalizing delignified almond shells with a photothermal coating. The systematic characterization confirms the successful formation of a cohesive, conductive PPy layer on the porous biomass substrate, which enhances light absorption and improves the photothermal effect. The designed evaporator PDAS achieves a high evaporation rate of 2.49 kg m−2 h−1, the photothermal conversion efficiency of 84.94%, and the water evaporation efficiency of 155%, under one-sun illumination, along with outstanding salt-resistance and long-term stability. When applied to seawater desalination and wastewater treatment, PDAS effectively removes salt ions, heavy metals, organic and pharmaceutical contaminants, producing freshwater that meets WHO drinking standards. The high-output performance of PDAS was revealed with the optimal open-circuit voltage of 288.9 mV and the power density of 16.78 mW/m2, at 3.5 wt% saline solution under one solar irradiation. This work demonstrates a sustainable strategy for transforming abundant biomass wastes into efficient solar evaporators for practical freshwater collection, wastewater treatment, and energy production.