Capacitive deionization electrode

The present invention relates to a process for the manufacturing of 3D reduced graphene oxide/Fe 2 O 3 material which comprises: (i) putting in contact a graphene oxide (GO) water dispersion with an aqueous solution of iron(II) sulfate; (ii) hydrothermal treatment; (iii) freezing the reaction product obtained in step (ii) at a temperature ¤ -5 °C; and (iv) lyophilisation. The invention also relates to the 3D reduced graphene oxide/Fe 2 O 3 material obtainable by the process, to electrodes for CDI devices comprising said material, and to a method for removing ions from a fluid, like saline water, using the capacitive deionization device of the invention, which includes applying a voltage to the electrodes while supplying said fluid into the capacitive deionization device.