Fractionation of Nanocellulose by Foam Filter

Abstract

The foam fractionation method was applied for nanocellulose. Experiments were carried out with enzymatically pretreated nano-fibrillated cellulose (NFC) from softwood, as well as commercial products. Narrow channels (plateaus) between bubbles prevent the flow of coarse particles along the water, so that foam acts like a filter. The advantage of the method is no risk of clogging, which could be a big problem for conventional filters or screens. Mean particle size (effective size by means of dynamic light scattering measurement) was reduced by foam fractionation, and the reduction range depended on the cellulose grade and the type of surfactant. The yield turned out to be low, probably because of particle aggregation due to the interaction with surfactant.

Keywords:

• foam
• fractionation
• microcellulose
• nanocellulose

ACKNOWLEDGEMENTS

The authors acknowledge CTP Centre Technique du Papier and J. Rettenmaier & Söhne GmbH for supplying samples. They also thank Riku Talja, VTT, for his valuable comments and critical reading of the manuscript. This research was part of the EU project SUNPAP (Scale-Up Nanoparticles in Modern Papermaking). The research leading to these results received funding from the European Community's 7th Framework Programme under Grant Agreement No 228802.