Using the fundamental adsorption equilibrium and kinetic parameters obtained from batch experiments, the mass transport and hydrodynamic behavior in the expanded bed of DEAE Spherodex M was analyzed with the breakthrough model. The results showed that the effect of particle size on breakthrough behavior was obviously greater than that of other parameters.The change of the time of 5% breakthrough, with increasing and decreasing mean particle diameter by a factor of 2, reached about 40% relative to that with the mean diameter, 88 μm. Secondary effects on expanded bed adsorption were film mass transfer and pore diffusion (<10%). Axial dispersion in solid phase had almost negligible effect on the adsorption process. Therefore, the assumption of even dispersion of adsorbent within the expanded bed may result in the model discrepancy to a great extent. It is considered that the breakthrough model can be further improved by taking into account particle size distribution in the expanded bed.
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