Polyketone was graft copolymerized with sodium styrene sulfonate (SSS) in the presence of additives such as Mohr’s salt and H₂SO₄. Fourier-transform infrared (FT IR) spectroscopy was used to characterize the grafted membrane. The water uptake (W.U), ion exchange capacity (IEC) and electrical resistance (E.R) of the membrane were measured to evaluate the physical properties of prepared membranes. The prepared membranes were applied to the membrane capacitive deionization process (MCDI), in which their salt removal rates were evaluated and compared to CDI (capacitive deionization).