Ambivalent role of calcium in the viscoelastic properties of extracellular polymeric substances and the consequent fouling of reverse osmosis membranes

The effects of polysaccharides composition on the interactions between EPS and RO membrane, including fouling, were studied in the presence of Ca2+. EPS originated from Pseudomonas aeruginosa PAO1 biofilms of the wild type and its Δpsl isogenic mutant was used for RO membranes fouling and QCM-D adso...

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Bibliographic Details
Published in:Desalination 2018-03, Vol.429, p.12-19
Main Authors: Ferrando, Diana, Toubiana, David, Kandiyote, Nitzan Shtreimer, Nguyen, Thanh H., Nejidat, Ali, Herzberg, Moshe
Format: Article
Language:English
Subjects:
Biofouling
Extracellular polymeric substances
QCM-D
Reverse osmosis
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Summary:The effects of polysaccharides composition on the interactions between EPS and RO membrane, including fouling, were studied in the presence of Ca2+. EPS originated from Pseudomonas aeruginosa PAO1 biofilms of the wild type and its Δpsl isogenic mutant was used for RO membranes fouling and QCM-D adsorption experiments. For the wild type strain EPS, bridging of alginates by Ca2+ led to an increase in both adsorption and rigidity of the adsorbed layer. However, no change was detected for the Δpsl EPS adsorption and the obtained layer showed reduced rigidity, likely due to the interference of Ca2+ with interactions between the polysaccharides composing the EPS. In agreement with the QCM-D results, once Ca2+ was added, an increased in RO fouling was observed with the wild type EPS, while reduced fouling was found for the Δpsl mutant EPS. The presence of an ATR-FTIR peak characterized glycosidic linkage only for the fouling layer formed by the EPS of the Δpsl mutant in the presence of Ca2+, suggested that Ca2+ alters the scaffold matrix of this EPS. The results of this study showed that polysaccharide composition in the EPS matrix significantly influences the interaction with Ca2+ as well as membrane fouling. •EPS matrix composition influences the interaction with calcium cations, which can either enhance or reduce fouling•Calcium cations alter the EPS matrix structure of Pseudomonas aeruginosa with deletion in the Psl polysaccharide gene cluster•Assessing adhesion and rigidity of the EPS layers provides prediction of RO membrane biofouling in lab scale
ISSN:0011-9164
1873-4464
DOI:10.1016/j.desal.2017.12.006