Details

Autor(en) / Beteiligte

• Xie, Ming
• Luo, Wenhai
• Guo, Hao
• Nghiem, Long D.
• Tang, Chuyang Y.
• Gray, Stephen R.

Titel

Trace organic contaminant rejection by aquaporin forward osmosis membrane: Transport mechanisms and membrane stability

Ist Teil von

• Water research (Oxford), 2018-04, Vol.132, p.90-98

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2018

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We investigated transport mechanisms of trace organic contaminants (TrOCs) through aquaporin thin-film composite forward osmosis (FO) membrane, and membrane stability under extreme conditions with respect to TrOC rejections. Morphology and surface chemistry of the aquaporin membrane were characterised to identify the incorporation of aquaporin vesicles into membrane active layer. Pore hindrance model was used to estimate aquaporin membrane pore size as well as to describe TrOC transport. TrOC transport mechanisms were revealed by varying concentration and type of draw solutions. Experimental results showed that mechanism of TrOC transport through aquaporin-embedded FO membrane was dominated by solution-diffusion mechanism. Non-ionic TrOC rejections were molecular-weight dependent, suggesting steric hindrance mechanisms. On the other hand, ionic TrOC rejections were less sensitive to molecular size, indicating electrostatic interaction. TrOC transport through aquaporin membrane was also subjected to retarded forward diffusion where reverse draw solute flux could hinder the forward diffusion of feed TrOC solutes, reducing their permeation through the FO membrane. Aquaporin membrane stability was demonstrated by either heat treatment or ethanol solvent challenges. Thermal stability of the aquaporin membrane was manifested as a relatively unchanged TrOC rejection before and after the heat treatment challenge test. By contrast, ethanol solvent challenge resulted in a decrease in TrOC rejection, which was evident by the disappearance of the lipid tail of the aquaporin vesicles from infrared spectrum and a notable decrease in the membrane pore size. [Display omitted] •Aquaporin forward osmosis (FO) membrane was examined for trace organic contaminants (TrOCs) rejection.•Dominant TrOC transport resistance remained from polyamide matrix rather than the embedded aquaporin vesicles.•Thermal stability of aquaporin membrane was evident by largely unchanged TrOC rejection after heat treatment.•Solvent exposure compromised aquaporin membrane pore structure as well as TrOC rejections.