Supramolecular alginate-polyethyleneimine composite hydrogels for enhanced uranium adsorption

This study reports Zn²⁺-mediated supramolecular composite hydrogels from the mixtures of sodium alginate and polyethyleneimine in the aqueous solutions. The composite hydrogels, consisting of both carboxylate and amino groups, show enhanced uptake capacity of 718 mg-U/g in a 20 mg/L uranium-spiked water at pH = 6. Furthermore, uranium uptake by the composite hydrogels, an endothermic and spontaneous process, follows pseudo-second-order kinetic model and Langmuir model. Importantly, the composite hydrogels can reach a high uranium uptake capacity of 692 mg-U/g in a simulated uranium wastewater with other metal ions. (author)