Considering that the total cost of protein therapeutics is shifting from cell culture to downstream purification, high productivity and high resolution separation techniques are in demand by the biopharmaceutical industry. Membrane chromatography offers several advantages over resin-based media, such as low pressure drop and facile scale up and set up. With the advent of biotechnology, worldwide demand for protein therapeutics is increasing rapidly. Therefore, high dynamic capacity membranes are essential to meet productivity demands. The objective of this research was to investigate dynamic adsorption capacities and protein fractionation behavior of newly developed adsorptive membranes. High dynamic capacity (>50 mg/mL BSA) ion-exchange membranes were produced by grafting functional polymer nanolayers from commercially available regenerated cellulose membranes using atom transfer radical polymerization. Separation parameters and dynamic adsorption capacities were measured using polymerization time as independent variable. Influence of ionic strength and volumetric flow effects on dynamic binding capacities were studied using an Akta purifier. A set of experiments was performed to determine efficiency and recovery of proteins from mixtures using membrane chromatography.