Separation of an aqueous mixture of 6-kestose/sucrose with zeolites: A molecular dynamics simulation

Abstract

Extra-large pore zeolites are a small subset (21) among the whole list of 253 zeolites available. The discovery of new low-glycemic sugars is very attractive as new healthy additives in the food field. This is the case of the 6-kestose. In the present case, it appears in a mixture in aqueous solution together with sucrose, the separation of the mixture being necessary. For this, we have focused on using certain zeolites with adequate pore sizes that allow the separation of this mixture, considering that since the molecular size of 6-kestose is greater than sucrose, it is necessary to promote the sorption of the latter, so that the first can be purified. After a computational screening of micropores of the 253 IZA zeolites, 11 zeolites were selected. Of these, 3 extra-large pore zeolites (AET, DON, ETR) have been proposed, which were analyzed in-depth through a molecular dynamics study considering the external surface. The results show that DON presents the most promising theoretical results for a selective sucrose/6-kestose separation. • Separation of dissacharide/trissacharide mixtures is important for agroalimentary process. • With 7.5/9.1 Å size of these sugars, extra-large pore zeolites might be used for separation. • Molecular dynamics of sucrose/kestose have been made on extra-large pore zeolites. • Models include large unit cells with: water, sugar, zeolite layers and reservoir (membranes). • Effects considered: external surface, terminal silanols, pore size, temperature, water.