A multiscale model is presented to elucidate protein adsorption and transport behaviors in ion-exchange chromatography (IEC) adsorbent particles that have either an open pore structure or charged dextran polymers grafted into the pores. Molecular dynamics simulation is used to determine protein diffusion and partitioning in different regions of the adsorbent pore, and these outputs are used in numerical simulations of mass transfer to determine the intraparticle protein concentration profile and the mass-transfer rate. Modeling results indicate that, consistent with experimental observations, protein transport can be faster in the polymer-grafted material compared to the open pore case. This occurs when favorable partitioning of protein into the polymer-filled pore space is combined with relatively high protein mobility within this region. The modeling approach presented here should be applicable to proteins and adsorbents with different properties, and could help elucidate the factors that control adsorption and transport in various IEC systems. (C) 2014 American Institute of Chemical Engineers