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On negative rejection of uncharged organic solutes in forward osmosis

Journal Contribution - Journal Article

Negative rejection of 7 alcohols in Forward Osmosis (FO) is reported. The alcohols used in this study are uncharged, hydrophilic organic solutes. It is shown that current membrane transport models are not capable of reproducing the rejection pattern presented here, and consequently, a new model is developed. The model relies on adsorption of the solutes to the membrane followed by coupled transport. Adsorption is caused by salting out of the solutes, while coupled transport is caused by their small size and hydrophilicity, yielding comparatively strong water-solute interactions. It is calculated that the solutes are enriched 4U+20135 times in the membrane compared to the feed solution. Coupled transport is also demonstrated using the same membrane and solutes in RO mode. The novel model yields an excellent fit, and model parameters are discussed.
Journal: Journal of Membrane Science
ISSN: 0376-7388
Volume: 548
Pages: 22 - 31
Publication year:2018