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Comparison of fouling by extracellular polymeric substances and polysaccharides in forward osmosis

Xie, Z., Nagaraja, N., Skillman, L., Li, D. and Ho, G.ORCID: 0000-0001-9190-8812 (2014) Comparison of fouling by extracellular polymeric substances and polysaccharides in forward osmosis. In: Water Convention. Singapore International Water Week, 1 - 5 June 2014, Singapore

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Fouling caused by extracellular polymeric substances (EPS), the products secreted by bacteria, has been regarded as one of significant contributors to deteriorating membrane separation performances. Most current laboratory studies on membrane fouling use selected model foulants, such as alginate, which may not typically represent bacteria-produced EPS. This study aimed to compare the fouling caused by naturally occurring EPS and commercial polysaccharides in forward osmosis (FO) separation, thus possibly suggesting the ideal polysaccharide model in the research of membrane fouling. Three types of commercial polysaccharides, namely alginate, xanthan and pullulan, as well as two types of EPS (EPS-RSW and EPS-FSW) extracted from the bacteria in raw seawater and filtered seawater (RSW 14 and FSW 6) were selected herein. Our results showed that the commercial polysaccharides and the naturally occurring EPS behaved differently in the FO fouling tests, which could be largely attributed to the difference in their solution viscosities. Both of the solutions consisting of EPS exhibited lower viscosities and led to higher permeate fluxes, in comparison to those of the solutions with the commercial alginate and xanthan polysaccharides. The use of pullulan caused the most similar flux change in FO separation to that by utilizing the EPS; thereby we suggest that pullulan be the preferred model polysaccharide to represent EPS in FO fouling research.

Item Type: Conference Paper
Murdoch Affiliation(s): School of Engineering and Information Technology
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