Construction of polyphosphazene-coated halloysite nanotube composite with in-situ released PO43− for efficient and rapid removal of uranium from wastewater

[Display omitted] •A novel halloysite nanotube modified by polyphosphazene was prepared for efficient U(VI) adsorption.•The HNT@PZM-500 possessed abundant binding groups for uranium and reached the adsorption equilibrium within 20 min.•The HNT@PZM-500 showed a high adsorption capacity of 1912.9 mg g−1.•The in-situ released PO43− ions of the HNT@PZM-500 composite accelerated the precipitation capture of uranium ions. To solve the problem of environmental pollution caused by U(VI) wastewater, it is an important and challenging topic to develop an adsorbent material with large adsorption capacity and fast U(VI) adsorption. In this paper, halloysite nanotube coated with polyphosphazene membrane (HNT@PZM) composite was constructed by chemical cross-linking approach, followed by the calcination process. HNT@PZM-500 composite was delicately loaded with highly dispersed PO43− groups on the surface, endowing the material with excellent uranium-binding ability. Especially, HNT@PZM-500 reaches adsorption equilibrium in 20 min, shows a remarkable adsorption capacity for uranium is 1912.9 mg g−1 and maintains a high removal rate of 98.78% for uranium in simulated uranium containing wastewater, which was much higher than that of other metal ions. The XRD, XPS and FT-IR analysis showed that PO43− groups uniformly anchored on the adsorbent was important in the adsorption of U(VI). During the action process, the in-situ released PO43− ions of the HNT@PZM-500 composite accelerated the precipitation capture of uranium ions. These results indicate that HNT@PZM-500 can be used for treatment of emergency U(VI) wastewater.