Unraveling ultrafiltration of polysaccharides with flow field flow fractionation

Membrane fouling in membrane bioreactors—Characterisation, contradictions, cause and cures

“…Calcium alginate and sodium alginate have distinctly different properties in that Ca-alginate has a higher gelling potential [109] due to its higher valence. Ca ions promote Na alginate aggregation [113,114] and influence the rate of flux decline, the reversibility of fouling and rejection. With increased Ca concentration, cake development became more dominant, and reversibility as well as alginate rejection were increased.…”

“…Ionic strength only had an impact in high fouling conditions where it decreased fouling. By flow field flow fractionation and multi-angle-light-scattering measurements, van de Ven et al [114] showed that Na alginate conformation was stretched in ultrapure water and collapsed in the presence of KCl. Up to a flux of around 50 L/(m 2 h), the dominant mechanism in pure water was concentration polarisation while above, fouling became more and irreversible.…”

Assessing membrane fouling potential of humic acid using flow field-flow fractionation

“…This is the main distinguishing feature of field-flow fractionation (FFF) with respect to classical chromatography that can neither directly predict retention for a given component nor extract chemical information straight from retention parameters. When FlFFF is coupled with multi angle light scattering (MALS) and refractive index detectors (RI), it can also reveal the conformation and behaviour of macromolecules in solution [25].…”

“…Van de Ven [25] used FlFFF coupled with MALS to study the conformation of alginate molecules under different ionic environments. They compared the FlFFF results with the actual crossflow filtration experiments using similar membrane to the FlFFF membrane.…”

Slow colloidal aggregation and membrane fouling

“…One possible way of experimentally checking this model was suggested by one of the reviewers of this paper. It would consist of using a field flow fractionation device as described by van de Ven et al [33], in which suspended particles can be focused in a thin boundary layer next to a porous wall. In such a system, the residence time in the device can be adjusted by controlling the cross-flow.…”