Study On Mechanism And Technology Of Foam Fractionation For Separating Surface Activite Materials In Foam Instability Systems

Foam fractionation is suitable for the separation of surface active materials,especially for the separation of surface active materials in the foam stability systems.However,few references are studied for the separation of surface active materials in the foam instability systems.This work studied different surface active materials in their foam instability systems and their performances in the process of foam fractionation according to the properties of different foam instability systems,then different foam fractionation technologies was developed,respectively.Firstly,using the lauryl sodium sulfate(SDS)with a strong surface active as the desired material,the effects of liquid phase height and the vertical sieve tray on the interfacial adsorption were studied,then a technology of three-stage continuous foam fractionation was developed for recovering SDS from its highly diluted solution with a 0.05 g/L concentration.Under the suitable conditions,the enrichment ratio and the recovery percentage were 5.0 and 65.8%,respectively.Secondly,using the whey protein with a weak surface active as the desired material,the effect of volumetric air flow rate increased by degrees on the separation property were studied,then a batch foam fractionation was developed for recovering whey protein from its diluted solution with a 0.10 g/L concentration.Under the suitable conditions,the enrichment ratio and the recovery percentage were 21.5 and 81.2%,respectively.Thirdly,using the casein with a weaker surface active as the desired material,the effects of the pore diameter of gas distributor and pH on the foam property were studied.Then a technology of foam fractionation coupled with isoelectric precipitation was developed for recovering casein from its diluted solution with a 0.10 g/L concentration.Under the suitable conditions,the enrichment ratio and the recovery percentage were 12.1 and 91.7%,respectively.Changing the operating conditions and developing new technologies were beneficial to the separation of surface active materials from a foam instability system in the foam fractionation process.The objective of this work was to supply some new ideas for the separation of surface active materials in the foam instability system,and expect to facilitate the industrialization of foam fractionation.