Full bagasse bio-waste derived 3D photothermal aerogels for high efficient solar steam generation

Nowadays, freshwater shortage, energy crisis and environmental pollution are the three major threats to human beings. Bio-waste is an important source of environmental pollutant emissions and a renewable resource with great potential. Herein, we develop a photothermal material based on bagasse for solar steam generation to relieve the freshwater crisis and mitigate environmental pollution caused by bio-waste. The mainly functional part of the solar-driven steam generator here is bagasse-based photothermal aerogel (B-PTA), which composes of carbonized bagasse (CB) and bagasse-derived cellulose fiber (BDCF). The B-PTA relying on CB can effectively absorb sunlight (~ 95%), resulting in a prominent light-to-heat ability. The B-PTA with DBCF has super-hydrophilicity, water transport and retention ability. Depending on the excellent light absorption and 3D water passageway, the B-PTA gives a water evaporation rate of 1.36 kg m –2  h –1 , and achieves a photothermal conversion efficiency of 77.34% under 1-sun illumination (1 kW m –2 ). The B-PTA shows remarkable stability that the efficiency without significant change after 20 cycles. In addition, the B-PTA can effectively desalt seawater and purify dye wastewater with natural sunlight. Therefore, turning bio-waste into valuable photothermal material for solar steam generation is possible. Due to the merits of low cost, scalability, environmental friendliness, B-PTA has the potential for real-world water purification. Graphical abstract