Particle-size optimization for a polymer coated silica gel in SMB chromatography for amino acid separation

The performance of silica gel as an adsorbent for a chromatographic separation has been recently improved by a special surface processing, in which high purity silica was prepared and then coated with silicone polymer. The superiority of such a polymer coated silica gel over conventional silica gels has been demonstrated previously. In this study, the polymer coated silica gel was applied to a simulated moving bed (SMB) chromatography for amino acid separation. Since the productivity of SMB is largely affected by the size of adsorbent particle, the determination of an optimal particle size for the polymer coated (P-C) silica gel is of importance. Thus, a systematic method of particle size optimization in the SMB for amino acid separation was developed. Based on the developed method, the optimal P-C silica size was determined for the SMBs with different pressure ratings. The results showed that the optimal P-C silica size occurred at the boundary between the pressure limiting and the mass transfer limiting regions. More importantly, the optimal P-C silica size was found to become smaller as the SMB with a higher pressure rating was employed. The results of this study can play an important role in tailoring the P-C silica gel to the SMB process for amino acid separation.