Preparation of aerogels from corn stalks and research on their properties and gelation behavior

Corn straw is a kind of agricultural biomass waste produced by the corn crop. It is a question of how to make effective use of this waste resource. Biomass aerogel is a good adsorbent which can be used to deal with water pollution. The direct use of non-component separated maize straw as the raw material in this paper can effectively reduce the experimental cost, simplify the experimental procedures and make efficient use of maize straw compared to traditional cellulosic raw materials. The inorganic salt lithium bromide (LiBr) solution was used as the solvent, and the environmentally friendly corn stover whole component aerogels (CA) with excellent performance were prepared by solvent replacement and freeze-drying. The optimum process for the preparation of aerogels was obtained using a single factor test method: 1:200, 150 ℃, 40 min, 70 wt% LiBr. The full-component aerogels from maize straw contained cellulose, hemicellulose and lignin, which indicated that the maize straw was effectively utilised. CA has a three-dimensional network pore structure, mainly composed of micropores and mesoporous pores. It has ultra-low density (9 mg/cm3) and excellent adsorption capacity for methylene blue and soybean oil (123.59 mg/g, 103.58 g/g). At the same time, the Rheolaser Master Microrheological (RMM) analyzer of French Formulaction Company was used to investigate the changes in solution gel process. The mean azimuth shift (MSD) curve of the sample was measured by optical microrheometer. The elastic factor (EI), macroscopic viscosity factor (MVI), solid-liquid equilibrium point (SLB), and photon free path (I*) values of the samples were calculated to explore the microstructure and rheological characteristics of the samples during the gel process. The gel behaviour and processes have been explored based on the analysis of these parameters. Potential applications of whole-component aerogels from corn stalks include building insulation, thermal insulation, light-blocking materials, and packaging materials.