Dr.-Ing. Andreas Hofmann

Continuous foam fractionation is a technique to separate surfactants from aqueous solutions based on their affinity to adsorb at gas-liquid interfaces. By introducing gas into a surfactant solution interfaces are generated in form of bubbles. The emerging foam, enriched with surface active molecules, is collected at the top of the column and then condensed to get a rich liquid product. Foam fractionation is regarded as a gentle and economical procedure for the separation and/or concentration of highly diluted protein mixtures, including active enzymes, which makes it applicable for the early stages of downstream processing.

In this research study the focus lies on a special operation mode of continuous foam fractionation, the so called “stripping mode”, in which a continuous counter-current flow of descending feed liquid and ascending foam is generated. The aim is the development of a mathematical model for continuous foam fractionation in stripping mode resulting in the ability for prediction of separation efficiency based on just a few experiments. Consequently the influence of process parameters on foam structure, hydrodynamics of the foam matrix and adsorption of surfactants at the gas-liquid interface by means of key parameters like the bubble size, the liquid content in the foam and the surface excess of the bubble should be investigated

Dissertation

• A. Hofmann
  Investigation of continuous foam fractionation in stripping mode
  TU Dortmund, 2017, Verlag Dr. Hut, München ISBN 978-3-8439-3277-63

Paper

•  A. Hofmann,G. Schembecker, J. Merz,
  Reply on " Comments on Role of bubble size for the performance of continuous foamfractionation in stripping mode"
  Colloids and Surfaces A:  Physicochemical and Engineering Aspects, doi.org/10.1016/j.colsurfa.2015.02.040
   
• A. Hofmann, G. Schembecker, J. Merz
  Role of bubble size for the performance of continuous foamfractionation in stripping mode
  Colloids and Surfaces A: Physicochemical and Engineering Aspects, doi.org/10.1016/j.colsurfa.2014.12.042

Oral presentations

• A. Hofmann, G. Schembecker, J. Merz
  Innovative downstream processing: Continuous foam fractionation of highly diluted protein mixtures
  ProcessNet-Jahrestagung und 31. DECHEMA-Jahrestagung der Biotechnologen 2014, Aachen, Deutschland (2014)

• A. Hofmann, G. Schembecker, J. Merz
  Role of bubble size for the performance of continuous foam fractionation
  10th European Conference on Foams and Applications EUFOAM, Thessaloniki, Greece (2014)

• J. Merz, A. Hofmann, E. van de Sandt, G. Meesters, A. Schaap, G. Schembecker
  Intensification of Downstream Processing by Foam Fractionation
  GVC / Dechema Vortrags- und Diskussionstagung: Effiziente Verfahren und Anlagen in der Bioverfahrenstechnik und Lebensmittelbiotechnologie, Bad Wildungen (2013)

Poster presentations

• A. Hofmann, J. Merz, G. Schembecker
  Continuous Foam Fractionation: Investigation of the Stripping Mode
  GVC / Dechema Vortrags- und Diskussionstagung: Biopharmazeutische Produktion, Freiburg (2012)
   
• A. Hofmann, J. Merz, G. Schembecker
  Continuous Foam Fractionation in Stripping Mode: Determination of Adsorption Isotherms
  9th conference on Foams and foam-related systems (fluid interfaces, thin films, surfactants, concentrated emulsions) EUFOAM, Lisbon, Portugal (2012)