Metal ion removal from acidic solutions with a high electrolyte concentration was completed through a modified polyacrylonitrile sorbent. The effects of the initial ion concentration, pH, the ionic strength, and anionic influence on the sorption behavior of the modified polymer were investigated. The distribution coefficient values for metal ions of various initial concentrations at 0.1 mol/L ionic strength increased in the following order: Mg2+ < Co2+ < Ni2+ < Zn2+ < Cd2+ < Cu2+ < Pb2+. The change of the ionic strength of the solution exerts a slight influence on the removal of copper, lead, and cadmium ions from aqueous solutions. Competition sorption studies were conducted at pH 4, ionic strength 0.5 mol/L, and with competing metal ions added at equivalent initial concentrations in the 2-component systems. Complete elution of metal ions from a loaded modified polymer was achieved with a nitric acid solution (pH 1.0-1.5) or by a subsequent treatment with 3% NH4OH solution. The modified polymer has a high selectivity toward lead and copper ions and could be used to remove and separate different amounts of these elements from metal-bearing solutions and industrial wastewater with a high electrolyte concentration.