Silk fibroin/carbon nanofiber composite aerogel for efficient and stable solar steam generation

The development of bio-based aerogel is an important solar evaporation issue owing to its environmental protection, sustainable water transportation, and intrinsic thermal management properties. Herein, silk fibroin (SF)/ carbon nanofiber (CN) composite aerogel (SCNA) was prepared by incorporating carbonized electrospun polyacrylonitrile (PAN) nanofibers into SF aqueous solution and then performing a freeze-drying process. The SCNA with optimized CN loading demonstrated outstanding solar absorbing capacity (99.89%) across the whole spectrum due to the synergy between the functional solar absorbing CN material and the SF skeleton (71.64%). With high porosity, the SF skeleton can encapsulate the CN, transport water, and suppress heat loss in solar evaporation. As a result, high evaporation rates were achieved for pure water (1.46 kg m(-2) h(-1)), 3.5% salty water (1.42 kg m(-2) h(-1)), and actual dyeing wastewater (1.43 kg m(-2) h(-1)). Besides, the SCNA could be reused more than ten times without performance degradation, assuring long-term efficient solar steam generation. Therefore, this work will stimulate more research on the use of biomass materials for solar evaporation, especially silk-based aerogel.

Automated summary

In this study, silk fibroin (SF)/ carbon nanofiber (CN) composite aerogel (SCNA) was prepared by incorporating carbonized electrospun polyacrylonitrile (PAN) nanofibers into SF aqueous solution. The SCNA showed excellent solar absorbing capacity and high evaporation rates, and could be reused multiple times, indicating its great potential for solar evaporation applications.