▎ 摘　　要

NOVELTY - Nanocomposite comprises at least one of carbon nanostructure, 3d transition metal salt and ferricyanide salt in a weight ratio of 0.01:0.1:0.5-0.1:1.5:2, where the carbon nanostructure is chosen from functionalized multiwalled carbon nanotube, graphene oxide or graphitic carbon nitride. USE - The nanocomposite is useful for electrochemical-switched ion exchange removal of heavy metals from an aqueous medium and radionuclide from wastewater, where the heavy metals are cadmium, mercury or cesium. ADVANTAGE - The nanocomposite has excellent adsorption properties, enhanced conductivity of ion exchange molecules, synergistic effect, increased conductivity of ion exchange molecules for efficient and speedy heavy metal decontamination with appreciable reusability, electrochemical adsorption and electrochemical desorption, and reuses modified electrode. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a process for electrochemical-switched ion exchange removal of heavy metal from an aqueous medium, involving electrochemically subjecting an aqueous medium with a three-electrode system comprising a nanocomposite modified electrode, silver/silver chloride as a reference electrode and platinum as a counter electrode, where the heavy metal is cadmium, mercury or cesium; and (2) a process for preparing the nanocomposite, involving (a) dispersing carbon nanostructure in polyvinylpyrrolidone to obtain a first mixture, (b) adding 3d transition metal salt and ferricyanide salt to the first mixture to obtain a reaction mixture and (c) heating the reaction mixture at 110-130 degrees C for 9-12 hours.