Zero valent iron/poly(amidoxime) adsorbent for the separation and reduction of U(vi)

Abstract

A magnetic nanocomposite of zero valent iron (ZVI)/poly(amidoxime) (PAO) was prepared by polymerization of acrylonitrile on the ZVI surface, followed by hydroxylamine (NH₂OH) treatment to convert the cyano group (–CN) into an amidoxime group (AO). The characterization results showed that PAO-stabilized ZVI magnetic composite (denoted as ZVI/PAO) was prepared successfully. ZVI/PAO was used as an adsorbent for the separation of U(VI) from solutions. The effect of environmental conditions on U(VI) adsorption onto ZVI/PAO was studied in detail. U(VI) adsorption on the ZVI/PAO surface reached equilibrium within 3 h, and the adsorption process is well described by the pseudo-second-order kinetics model. Adsorption isotherms of U(VI) on the ZVI/PAO surface can be well fitted by the Langmuir model, and the maximum adsorption capacity was calculated to be 206 mg g⁻¹ at T = 298 K and pH = 5.0. Experimental results highlighted the application of ZVI/PAO as an adsorbent for the efficient separation of U(VI) and reduction of U(VI) to U(IV) from aqueous solutions.