Development of waste silk-based aerogel: for continuous treatment of oily wastewater and thermal insulation.

Biomass-based aerogel with lightweight and high sustainability is desired for various applications such as thermal insulation, self-cleaning, and oil contaminant removal. However, systematic comparison and thorough investigation are required to understand the effects of constituent materials and structures on the application properties of biomass-based aerogels. Herein, the construction of superhydrophobic aerogel with controllable hierarchical structure and great reusability was optimized applying a novel design based on the waste silk-derived microfibrillated fibers and microfibrillated aramid fibers. The achieved aerogels possessed ultra-high porosity (99.7 %), strong hydrophobicity (water contact angle of 172.6°), good mechanical property, self-cleaning and low thermal conductivity (0.068 W/(m·K)). Furthermore, the aerogel could selectively absorb waste oil and organic solvent from wastewater with ultra-high absorption capacity of 236.6 g/g, showing outstanding reusability and sustainability. This strategy provided a facile design of biomass-based aerogels from natural fibers, and the derived advanced multifunctional aerogel was expected to be useful for absorption and thermal management applications.