▎ 摘　　要

NOVELTY - Composite material comprises activated carbon and thiol-functionalized graphene oxide which is coated on the activated carbon. USE - Composite material. ADVANTAGE - The composite material improves the removal efficiency and discharge efficiency. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a electrode, which comprises composite material; (2) a capacitive deionization cell, which comprises first electrode and second electrode, first electrode is electrode; (3) a water purification system, which comprises one or more capacitive deionization cells, electrical circuit for controlling operation of the one or more capacitive deionization cells and filter, filter is in fluid communication with one or more capacitive deionization cells; and (4) a method for removing heavy metal ion from water supply, which involves applying voltage to one or more capacitive deionization cells, directing water supply through one or more capacitive deionization cells and adsorbing the heavy metal ion at the first electrode, heavy metal ion is a lead, copper, cadmium, nickel, or mercury ion.