Ion cross-linking assisted synthesis of ZIF-8/chitosan/melamine sponge with anti-biofouling activity for enhanced uranium recovery

Abstract

Micro/mesoporous powder structures and biofouling of marine microorganisms directly limit the potential of zeolite frameworks in uranium recovery from seawater. Herein, an anti-biofouling zeolite framework-8/chitosan/melamine sponge adsorbent with a three-dimensional porous structure was prepared successfully using zinc ions and chitosan as adjuvants to promote the growth of zeolite framework-8 on the surface of melamine sponge. The mechanical and anti-biofouling properties of the sponge were determined by compression and algae tests. Relative to the zeolite framework-8 powders, the zeolite framework-8/chitosan/melamine sponge exhibited superior mechanical and anti-biofouling properties with 0.565 MPa of compressive stress and a 35% algae cell death rate. The adsorption capacities of the zeolite framework-8/chitosan/melamine sponge were 129.90 mg g⁻¹ at pH 8.0 and 95.47 mg g⁻¹ at the fifth adsorption–desorption cycle, which were higher than that of ZIF-8 powder (91.45 mg g⁻¹). Furthermore, the excellent low-concentration U(VI) adsorption performance of zeolite framework-8/chitosan/melamine in natural seawater (Bohai) also confirmed its practical application potentiality.