Abstract
We demonstrated a novel AquaporinZ (AqpZ)-incorporated double-skinned forward osmosis (FO) membrane by layer-by-layer (LbL) assembly strategy. Positively charged poly(ethyleneimine) (PEI) and negatively charged poly(sodium 4-styrenesulfonate) (PSS) were alternately deposited on both the top and bottom surfaces of a hydrolyzed polyacrylonitrile (H-PAN) substrate. Subsequently, an AqpZ-embedded 1,2-dioleloyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dioleoyl-3-trimethylammonium- propane (chloride salt) (DOTAP) supported lipid bilayer (SLB) was formed on PSS-terminated (T-PSS) membrane via vesicle rupture method. The morphology and structure of the biomimetic membranes were characterized by in situ atomic force microscopy (AFM), scanning electron microscope (SEM), Fourier transform infrared spectrometer using the attenuated total reflection technique (ATR-FTIR), and contact angle. Moreover, the FO performance of the resultant membrane was measured by using 2 M MgCl2 solution as draw solution and deionized (DI) water as feed solution, respectively. The membrane with a protein-to-lipid weight ratio (P/L) of 1/50 exhibits 13.2 L/m2h water flux and 3.2 g/m2h reversed flux by using FO mode, as well as 15.6 L/m2h water flux and 3.4 L/m2h reversed flux for PRO mode (the draw solution is placed against the active layer). It was also shown that the SLB layer of the double-skinned FO membrane can increase the surface hydrophilicity and reduce the surface roughness, which leads to an improved anti-fouling performance against humic acid foulant. The current work introduced a new method of fabricating high performance biomimetic FO membrane by combining AqpZ and a double-skinned structure based on LbL assembly.
Highlights
Aquaporins (AQPs) are a kind of transmembrane water channel protein that selectively allow the transport of water molecules because of their narrow channels with a dimensional structure and distinct charge characteristics [1]
In the forward osmosis (FO) mode, dilutive internal concentration polarization” (ICP) occurs within the membrane support layer as water permeates across the membrane from the feed solution (FS) to the draw solution, which usually causes a severe decline in water flux, so the flux experiments were performed in the FO mode to confirm that the double-skinned FO membrane could reduce the ICP level
Our work provided a novel structure of AqpZ-incorporated FO membranes, which enhanced the anti-fouling stability and offers a clear advantage for FO applications
Summary
Aquaporins (AQPs) are a kind of transmembrane water channel protein that selectively allow the transport of water molecules because of their narrow channels with a dimensional structure and distinct charge characteristics [1]. Wang et al reported on an AqpZ-embedded supported lipid bilayer (SLB) by using an electrostatic layer-by-layer (LbL) deposition method to prepare a robust biomimetic membrane, which demonstrated an excellent nanofiltration (NF) performance [4]. The electrostatic LbL deposition method, which is based on the alternating adsorption of oppositely charged components [20,21], has been demonstrated to form a robust biomimetic membrane [4]. We used this method to fabricate T-PSS membranes on the basis of porous substrates. FO performances and fouling tests of AqpZ-incorporated double-skinned FO membranes were investigated and compared with the single-skinned FO membranes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
