A novel functional absorbent, polyvinyltetrazole fiber (PVT), was made from polyacrylonitrile fiber through [3+2] azide-nitrile cycloaddition reaction of cross-linked polyacrylonitrile with sodium azide. The obtained PVT showed strong adsorption ability to the investigated heavy-metal ions, Cu(II), Cd(II), Ni(II), and Zn(II), with the maximum adsorption capacities of 323, 278, 200, and 175 mg g-1, respectively. The adsorption process was described as an ion exchange mechanism. The adsorption isotherms were better fitted for Langmuir model, while adsorption kinetics was better described by the pseudo-second order equation. In addition, the tested heavy-metal ions could be desorbed efficiently from PVT at pH below 2.0, and the adsorption capacity of the regenerated PVT had no loss until seven cycles. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012