Removal of impurities from protein foam in foam fractionation process by wash water addition.


Removal of impurities from protein foam in foam fractionation process by wash water addition.

Keshavarzi, B.; Krause, T.; Schwarzenberger, K.; Eckert, K.; Ansorge-Schumacher, M. B.; Heitkam, S.

This work introduces a simple and efficient method to remove the impurities from a protein foam
through washing the foam in a foam fractionation process (figure 1). Since the protein molecules
adsorb irreversibly on the air interface, they do not desorb upon wash water addition and are
transferred to the foam outlet. However, the entrained substances are directed downward by
wash water to the drain outlet together with the liquid. Here, we performed experiments on
bovine serum albumin (BSA), as a model protein and NaCl salt, as a model of soluble impurities.
The experiments were conducted in a glass foam fractionation cell, where the liquid level was
kept constant. The wash water was added on the foam top with different flow rates and BSA and
NaCl concentrations were measured at the outlets for further analysis. The influence of initial
bubble size and the wash water rate on the purification efficiency were investigated. The results
revealed that the wash water displaces the entrained liquid in the foam and reduces the salt
content at the foam outlet. The process shows higher salt removal for higher wash water rates as
well as for foams with larger bubble sizes, where up to 93% of the salt was removed from the
main solution in a steady state process. The washing efficiency is also influenced by air flow
rate. Salt removal is enhanced in principle at lower air flow rates. However, the foam stability
becomes an important issue at smaller air flow rates, since the increased foam collapse
significantly reduces the foam flow to the outlet.

  • Lecture (Conference)
    EUFOAM, 03.-06.07.2022, Krakow, Poland

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Publ.-Id: 35553