Mechanically robust and highly permeable AquaporinZ biomimetic membranes

Abstract

Seawater desalination and water reuse using membrane technology can provide a sustainable water supply to the world if such processes can be more energy-efficient. To harness the highly efficient water transport used by nature, it is proposed to incorporate trans-membrane water channel, AquaporinZ (AqpZ), into biomimetic membranes. However, the biomimetic membranes are intrinsically too fragile to be used in water purification. Here, we report a robust vesicular biomimetic membrane design and the synthesis route. The membrane is formed by cross-linking AqpZ-embedded block copolymer vesicles, followed by immobilizing vesicles on the membrane support via covalent binding, and then stabilizing through an optimized layer-by-layer polydopamine (PDA)-histidine (His) coating process. As compared with commercially available HTI membranes, the AqpZ-embedded vesicular membrane shows an order-of-magnitude increment in water flux (17.6L/m2/h) with high salt retention (91.8%) when using 6000ppm NaCl as the feed and 0.8M sucrose as the draw solute in the forward osmosis operation. Thus, the vesicular membrane design may provide new insights into the design and fabrication of Aqp-embedded biomimetic membranes. © 2013 Elsevier B.V.