Chitosan-based aerogel with anti-swelling for U(VI) adsorption from aqueous solution

Due to the high swelling ratio, the use of chitosan-based composites for adsorption of U(VI) from wastewater is limited. To overcome this shortcoming, a novel type of hierarchical porous chitosan-based aerogel (CS-PTADMAs) with anti-swelling is successfully prepared via cross-linking chitosan with the cross-linker PTA-DMA, which is synthesized by p-phthalaldehyde (PTA) and 3,5-diaminobenzoic acid (DMA). There is no significant volume expansion of the aerogel after soaking in ultrapure water for 1 week, indicating it has good swelling property. In addition, the CS-PTA-DMA aerogel has a high U(VI) adsorption capacity of 160 mg/g (308 K, pH 6). The adsorption behavior of CS-PTA-DMA to U(VI) is coordinate to the pseudo-second-order kinetic model and Freundlich isothermal model, which is spontaneously endothermic. Moreover, the adsorption mechanism is also investigated in details. These findings are crucial for the development of practical application uranium adsorbents.