Preparation of amino-functionalized starch-based adsorbent and its adsorption behavior for uranyl ions

Starch not only has the advantage of inexpensive and biodegradable compared to other adsorbed materials but also contains a large amount of chemically modified hydroxyl groups. Using starch as the raw material, an amino-functionalized starch-based adsorbent was prepared by a three-step reaction of esterification-crosslinking- aminolysis. The samples were characterized by FTIR, EDS, and XPS. The adsorption performance of amino-functionalized starch-based adsorbents for uranyl ions in aqueous solutions was studied, and the adsorption kinetics and adsorption thermodynamics were analyzed. The results show that after the starch-based adsorbent is functionalized with amino groups. Its adsorption performance for uranyl ions is significantly improved. The adsorption behavior of amino-functionalized starch-based adsorbents for uranyl ions conforms to the Langmuir isotherm adsorption model and the quasi-second-order adsorption kinetic equation. The adsorption process mainly depends on the coordination and chelation between uranyl ions and –NH2 on the surface of the adsorbents. And the adsorption process is exothermic. Finally, satisfactory results were obtained under gentle conditions. Under the conditions of pH 6, C0 of 35 mg/g, T of 25 ℃, m of 0.25 g/L, and t of 5 h, the adsorption capacity of the adsorbent for uranyl ions is 118.92 mg/g. This shows that the amino-functionalized starch-based adsorbent has potential application prospects in terms of nuclear energy-containing uranium wastewater.