Review on the application of biomass-based aerogels in the field of thermal insulation

The continuous progression of industrialisation and the burgeoning global population have precipitated the nonrenewable energy crisis and exacerbated environmental problems, thereby stimulating a huge demand for production of environmentally friendly materials. Typically, biomass-based aerogels (BAs) derived from cellulose, chitosan (CS), lignin, and alginate have been gradually captivating the attention of researchers owing to their high specific surface area, substantial porosity, low density, porous architecture, and biodegradability. In this review, we demonstrate the sustainability of BAs by contrasting the overall advantages or disadvantages of BAs with those of synthetic alternatives in terms of cost, insulation performance, and planetary boundaries. In addition, the aerogels based on biomass in recent years are summarized, including thermal insulation mechanisms, the raw materials, test methods, preparation approaches (focusing on the use of crosslinking and drying methods in the preparation process), as well as the wide-ranging applications. Furthermore, we offer the incisive insights into the challenges and prospective opportunities for BAs. The up-to-date summary and discussion will be beneficial to the development of functional BAs, which can improve resource utilization efficiency, thereby catalyzing the advancement of green technology.