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The purpose of this work was to recover isoflavone aglycones from industrial soy whey wastewater, where the isoflavone aglycones mainly existed in the form of β-glycosides. First, foam fractionation was used for effectively concentrating the total soy isoflavones, including isoflavone aglycones and β-glycosides, from the wastewater. Fourier transform infrared spectroscopy indicated the existence of complexes of soy isoflavones and soy proteins. When soy proteins were used as the collectors, a high enrichment ratio of 3.68 was obtained under the optimal operating conditions of temperature of 50 °C, pH of 5.0, volumetric air flow rate of 100 mL/min, and loading liquid height of 400 mm. Subsequently, acidic hydrolysis was used for hydrolyzing β-glycosides in the foamate into aglycones. Using response surface methodology, a hydrolytic percentage could reach 96% under the optimum hydrolysis conditions of hydrolytic temperature of 80 °C, hydrochloric acid concentration of 1.37 mol/L, and hydrolytic time of 90 min.

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The feasibility of recovering bioactive substances without surface activity from their aqueous solutions was studied using biosurfactants as collectors. For recovering the isoflavones from the soy whey wastewater, a two-stage batch foam fractionation was developed using the soy proteins as collectors. The results showed that when the conditions of the first stage were temperature of 60°C, pH of 5.0, volumetric air flow rate 80 of mL/min, and loading liquid volume of 400 mL, a high isoflavones enrichment ratio of 4.05 was obtained and the residual solution could be used as the feeding solution of the second stage. When the conditions of the second stage were temperature of 25°C, pH of 5.0, and volumetric air flow rate of 150 mL/ min, the soy proteins concentration in the residual solution could decrease to 622 mg/L. By reusing the foamate of the second stage as the feeding solution of the first stage, the total isoflavones recovery percentage reached 87.72%.

A series of ionic liquids were used as a co-solvent in the reaction of one-pot synthesis of phenols from aromatics and hydroxylamine. Then an eco-friendly catalytic system, i.e., [HSO3-bmi [CF3SO3]-H2O-HAc media with (NH4)6Mo7O24·4H2O catalyst, was designed for the reaction. The results showed that aromatics were successfully hydroxylated to give the corresponding phenols. Recycling experiments suggested that the catalytic system was stable enough to be recycled.