Methyl 4-hydroxybenzoate nanospheres anchored on poly(amidoxime)/polyvinyl alcohol hydrogel network with excellent antibacterial activity for efficient uranium extraction from seawater

Abstract

Designing an adsorbent with excellent practical application on uranium extraction from seawater is extremely difficult but urgent. Here, the poly(amidoxime) (PAO)/polyvinyl alcohol (PVA)/methyl 4-hydroxybenzoate (MeP) hydrogel (named as PP@MeP-H) was prepared using a simple and controllable ultralow temperature-solvent exchange two step strategy. With assistance of solvent exchange, MeP nanospheres anchored on the hydrogel network showed excellent antibacterial activity during the uranium adsorption from seawater. Furthermore, the hydrogel with 3D network porous structure allows uranium to easily and rapidly spread into its interior owing to its abundant porous and anti-biological pollution ion channels, which ensures maximum utilization of the effective adsorption sites on this adsorbent. The superior uranium extraction capacity achieved 162.64 mg g−1, and the sample shows excellent stability and reusability. Interestingly, when the pH close to natural seawater, PP@MeP-H showed the highest uranium adsorption activity (153.30 mg g−1), and for 500 L of natural seawater, the uranium adsorption capacity achieved 3.12 mg g−1 after 21 days. Furthermore, experimental results showed that the O and N atoms of amidoxime group act as main bonding sites for uranium adsorption. As the discussed above, PP@MeP-H has excellent potential of uranium adsorption from natural seawater.