Foam fractionation for recovering whey soy protein from whey wastewater: Strengthening foam drainage using a novel internal component with superhydrophobic surface

Abstract Whey soy proteins (WSP) are acid soluble proteins massively existed in the whey wastewater from the process of soybean protein isolate (SPI) manufacture and they possess high nutritive values and good functional properties. For effectively recovering WSP from the whey wastewater by using foam fractionation, a novel foam column fitted with the cross internal covered by a superhydrophobic coating (SHC) was developed to strengthen foam drainage. The experimental results indicated that SHC could significantly strengthen foam drainage through decreasing the flow resistance of the interstitial liquid in the exterior channels at room temperature. The suitable length of the cross internal with SHC was 600 mm and the drainage velocity was dramatically accelerated when it was installed at 50 mm from the top of the column. Under the suitable operation conditions, enrichment ratio and recovery percentage of WSP reached 10.5 and 82.3%, respectively. This work provides a new light for strengthening foam drainage at room temperature and facilitates of the industrialization of foam fractionation.