Bis-substituted amino acid functionalized chitosan aerogels: High uranium adsorption capacity and antibacterial properties.

Based on the goal of "carbon neutralization and carbon peaking", it is still challenging to develop a high adsorption performance and environmentally friendly material for uranium extraction. We proposed a new idea of "Three-Dimensional Environmental-Friendly". A series of amino acid bis-substituted chitosan aerogels (C-1, C-2, C-3, C-4 and C-5) were prepared by ice template method and selective substitution reaction in water environment. Among them, C-3 adsorbent has the antibacterial properties of gram-positive bacteria, gram-negative bacteria and marine bacteria, which is more suitable for uranium adsorption in complex environments. Also, C-3 adsorbent solves the shortcomings of poor adsorption property and easy to cause secondary pollution during modification of traditional chitosan materials. The selectivity and adsorption capacity of uranium are further improved by the unique functional groups of serine residues. At pH = 7, the maximum adsorption capacity reaches 606.32 mg/g. In addition, C-3 adsorbent have excellent selectivity and stability. The synergistic effect of coordination, electrostatic interaction and intraparticle diffusion between C-3 adsorbent and uranium may be the key to its high adsorption performance. The high performance of chitosan adsorbent provides a new idea for the design and application of green and efficient uranium adsorption materials.