Microwave assisted synthesis of ion-imprinted polyacrylonitrile fibre via one-step phosphorylation for selective recovery of Dy(III) from wastewater

The selective recovery of Dy(III) from wastewater is highly desirable. Ion imprinted fibers are considered as attractive adsorbents due to their low flow resistance, high selectivity and ease of recovery. Phosphate groups with strong affinity to rare earth ions are widely used to construct ion imprinted polymers. However, current approaches for introducing phosphate groups into fibers suffer from the low grafting percentage and long reaction time because of the complicated procedures. Herein, a simple one-step phosphorylation method was explored to simultaneously introduce highly active primary amine and phosphate groups into polyacrylonitrile fiber (PANF) under microwave assisted conditions. Additionally, an unique Dy(III) ion-imprinted fibrous adsorbent (IIF-3) was fabricated by cross-linking of the aminated and phosphorylated PANF for selective capture of Dy(III) from wastewater. The advantages of this innovative technology in synthesizing fibrous adsorbent include: short reaction time, high phosphonic content and good mechanical property. In addition, batch sorption tests reveal that the uptake of Dy(III) onto IIF-3 is well described by the Langmuir isotherm and pseudo-second order models. Besides, IIF-3 exhibits a high adsorption selectivity for Dy(III) in multi-component system with different types of interfering ions. Importantly, benefiting from the protective effect of surface imprinting layer, the IIF-3 not only achieves enhanced mechanical property, but also shows satisfied reusability in six times application. This work opens a novel path to prepare phosphorylated ion-imprinted fibers and sheds light on their applications for selective capture of Dy(III) from wastewater.