Influences of the constraints of a separation task on the optimal selection of a cation exchanger resin

Abstract

One important step in designing preparative chromatographic separation units is the selection of a well-performing adsorbent. Such selection is often based on selectivity factors which are calculated based on experimentally determined adsorption isotherms. Influences of constraints of the separation tasks, like purity demand, on the optimal selection are usually not considered. In this contribution, influences of the constraints of a separation task on the optimal adsorbent were investigated. First, a previously published model-based optimisation of the adsorbent selection using correlations between structural adsorbent properties with model parameters were extended by influences of particle size and ionic form of resins (Leipnitz et al., 1610). Model parameters of glucose and xylose for cation exchanger resins in Na+- and Ca2+-form with varying degrees of cross-linking and particle sizes were experimentally determined in a sequential parameter determination approach (Altenhoner et al., 1997). Correlations between the structural properties of resins and the model parameters were derived and applied in optimisation case studies. Following this approach, optimal structural properties were identified, increasing the volume-specific productivity of a separation of glucose and xylose, significantly. Further, the purity demand and feed composition were varied in different case studies, revealing the influences of constraints of a separation task on structural properties of optimal resins.