Separation of isoflavone aglycones using chitosan microspheres from soy whey wastewater after foam fractionation and acidic hydrolysis

• The separation of isoflavone aglycones from soy whey wastewater was studied.
• Chitosan microspheres was be used as bio-adsorbents for separating isoflavone aglycones.
• The kinetics and thermodynamics of adsorption process were intensively investigated.
• Chitosan micropheres have excellent reusability for separating isoflavone aglycones.
• An integral process was designed for recovering isoflavone aglycones from wastewater.

The purpose of this work was to separate isoflavone aglycones from soy whey wastewater after foam fractionation and acidic hydrolysis using chitosan microspheres. The maximal equilibrium adsorption capacity could be obtained at pH 6.0. The adsorption isotherm fitted better to the Freundlich equation model and the adsorption was an exothermic and spontaneous physical process. The maximal desorption ratio of isoflavone aglycones could reach 94.82% by using 70% (v/v) ethanol as desorption solution. Moreover, the regenerated chitosan microspheres could be reused for separating isoflavone aglycones from the feeding solution up to five times without compromising their function.