Modelling and analysis of the continuous affinity-recycle extraction process: a case of specific elution with low molecular weight competitive inhibitor

Abstract

The continuous affinity-recycle extraction (CARE) process of specifie elution with low molecular weight competitive inhibitor is mathematically modelled taking into account the presence of membrane rejections to the components in a crude broth. The process performance, defined as purification factor (PF) and recovery yield (REC), is analyzed by computer simulations. The results show that for constant affinity systems (ligate and ligand as well as inhibitor) and operating conditions an optimal value of the inhibitor concentration exists to give maxima of REC and PF, and the optimal value decreases with the increase of the affinity binding constant of ligate and inhibitor. Although the increase in affinity-recycle flow rate results in the decrease of PF, an optimal value of the affinity-recycle flow rate exists to show a maximum of REC. Hence in the process design the selection of the affinity-recycle flow rate is also of importance to obtain higher REC and PF simultaneously. The consideration of membrane rejections will in practice be useful to analyse the separation of a binary broth using ultrafiltration membranes which reject to the components. For a multicomponent broth, however, membranes without rejection to all components should be employed to simplify the process design and optimization. In general, the model is useful to design a CARE process using nonporous microparticles or macromolecules as affinity supports.