Pure biomass high-flame-retardant aerogel prepared by two-step crosslinking

The invention discloses a method for preparing pure biomass high-flame-retardant gas gel through two-step crosslinking. The preparation method comprises the following steps: dissolving phytic acid in deionized water, adding sodium alginate, uniformly stirring, pouring into a mold, putting into an oven to sufficiently crosslink, completely freeze-drying hydrogel, and freeze-drying to obtain the sodium alginate/phytic acid composite aerogel. And immersing the alginate/phytic acid aerogel into a saturated CaCl2 ethanol solution, washing and freeze-drying to obtain the alginate/phytic acid aerogel prepared by a two-step cross-linking method. According to the preparation method, pure biomass-derived sodium alginate and phytic acid are taken as raw materials, the characteristics that phytic acid can be taken as a flame-retardant component and can be physically crosslinked with hydroxyl of sodium alginate and the crosslinking effect of Ca < 2 + > on sodium alginate are utilized, two-step crosslinking is carried out