Novel CaCO3/chitin aerogel: Synthesis and adsorption performance toward Congo red in aqueous solutions

In this study, chitin aerogel doped with nano-calcium carbonate (CaCO 3 /chitin aerogel) was prepared by dissolving chitin in Na 2 CO 3 /Ca (OH) 2 /urea system followed by epichlorohydrin (ECH) addition as a cross-linker and then freeze-drying of the hydrogel. The as-obtained CaCO 3 /chitin aerogel showed good adsorption properties toward the adsorption of Congo Red (CR) with maximum adsorption capacity reaching approximately 266.4 mg·g −1 . Besides, the adsorption capacity was affected by the initial concentration and pH. The adsorption kinetics revealed a second-order kinetics model of CaCO 3 /chitin aerogel toward CR, and the adsorption process was controlled by both the liquid film diffusion and intra-particle diffusion. In sum, chitin aerogel looks promising as an effective adsorbent for anion dye adsorption. The cost-effective and eco-friendly developed approaches are also of great interest for future environmental remediation.