Biomass-derived photothermal carbon aerogel for efficient solar-driven seawater desalination

Solar-driven interface evaporation is an effective method to produce fresh water to alleviate the shortage of water resources. However, there are still challenges in preparing photothermal conversion materials with high evaporation rate, high photothermal conversion efficiency and low cost. Herein, a 3D carbon aerogel with excellent photothermal conversion performance was prepared by using environmental-friendly biomass materials as the matrix. The hydrophilic 3D photothermal carbon aerogel with low thermal conductivity was prepared by depositing polydopamine and loading Cu nanoparticles (CuNPs) on the surface of bacterial cellulose nanofibers. The deposition of PDA improved the mechanical properties and hydrophilicity of carbon aerogel, and the introduction of CuNPs further enhanced the photothermal conversion performance of carbon aerogel. Interestingly, the side temperature of 3D carbon aerogel was lower than the ambient temperature in the evaporation process, which could absorb energy from the environment and significantly improve the photothermal conversion efficiency, giving rise to the impressive water evaporation rate (2.07 kg·m−2·h−1) and photothermal conversion efficiency (115.36%) of 3D carbon aerogel under 1 sun. Moreover, the prepared 3D carbon aerogel had excellent purification effect on seawater, strong acid/alkali and dye solution, demonstrating its broad application prospect in the field of solar-driven seawater desalination.