Highly adherent Ti3C2Tx nanosheet-loaded amidoxime polyacrylonitrile composite membrane for uranium extraction

Abstract

Uranium is the main element of nuclear energy production, so the current global energy scarcity can be solved by uranium enrichment. The total amount of uranium in the ocean is huge, but how to extract uranium from the ocean efficiently and conveniently has become a hot issue nowadays. Polydopamine (PDA) from the self-polymerization of the mussel substance dopamine (DA) improved the adhesion of Ti3C2Tx (MXene) nanosheets to amidoxime polyacrylonitrile (PAO) support membrane to form amidoxime polyacrylonitrile composite membrane loaded with MXene nanosheets for uranium capture (PDA@M/PAO). The obtained maximum uranium adsorption capacity of PDA@M/PAO composite membrane can reach up to 14.85 g/m2 (499.9 mg/g), which was significantly higher than that of single PAO membrane. Kinetic fitting indicated that the adsorption was chemical adsorption, and isothermal model indicated that the adsorption was consistent with Langmuir adsorption, which was monolayer adsorption. After eight adsorption–desorption cycles, the adsorbent still retained 83 % of the elution rate, indicating that the adsorbent had great stability and recyclability. Due to its high adsorption capacity and excellent cycling stability, PDA@M/PAO composite membrane will provide a new strategy for uranium enrichment.