A highly selective and sensitive reusable colorimetric sensor for Ag+ based on thiadiazole-functionalized polyacrylonitrile fiber

Abstract

A thiadiazole-functionalized polyacrylonitrile fiber (DPTD-PAN_PF) qualitative colorimetric sensor was prepared for the first time, and its absorption properties were investigated in detail. The obtained sensor exhibits excellent chelating selectivity towards Ag⁺ without interference by other co-existing ions (Pb²⁺, Hg²⁺, Cd²⁺, Zn²⁺, and Cu²⁺) and generates a remarkable visual color change from yellow to red-brown over a wide pH range from 3 to 12. The DPTD-PAN_PF for Ag⁺ has a naked-eye detection limit of 11 ppb (only one in ten thousand of that of the small molecule DPTD) and a much higher saturation absorption capacity of 149 mg g⁻¹. Moreover, the fiber can be repeatedly used more than 50 times. In summary, this fiber sensor possesses the advantages of excellent selectivity, lower detection limit, outstanding absorption capacity and reusability to detect and remove Ag⁺ from water.