Oxadiazole-Functionalized Fibers for Selective Adsorption of Hg²⁺

Six kinds of 1,3,4-oxadiazole-functionalized fibers were prepared to evaluate the adsorption capacity for Hg²⁺. Finally, a functionalized fiber (PAN_p‑PMODF) with the best adsorption performance was selected for further research. The PAN_p‑PMODF fiber was characterized by infrared (IR), elemental analysis (EA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The PAN_p‑PMODF shows excellent selectivity for mercury ions in a mixed heavy metal ion solution (Hg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, Ag⁺, Co²⁺, Cr³⁺, Cu²⁺, and Cd²⁺), and it can reduce the concentration of Hg²⁺ to 44 ppb in the actual sewage, which is of great practical value for the treatment of mercury pollution. Furthermore, the adsorbed Hg²⁺ can be desorbed completely by dilute HNO₃ and the PAN_p‑PMODF can be reused many times with excellent recyclability.