TY - JOUR
T1 - A Path to Ultraselectivity
T2 - Support Layer Properties to Maximize Performance of Biomimetic Desalination Membranes
AU - Werber, Jay
AU - Porter, Cassandra J.
AU - Elimelech, Menachem
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/9/18
Y1 - 2018/9/18
N2 - Reverse osmosis (RO) has become a premier technology for desalination and water purification. The need for increased selectivity has incentivized research into novel membranes, such as biomimetic membranes that incorporate the perfectly selective biological water channel aquaporin or synthetic water channels like carbon nanotubes. In this study, we consider the performance of composite biomimetic membranes by projecting water permeability, salt rejection, and neutral-solute retention based on the permeabilities of the individual components, particularly the water channel, the amphiphilic bilayer matrix, and potential support layers that include polymeric RO, nanofiltration (NF), and porous ultrafiltration membranes. We find that the support layer will be crucial in the overall performance. Selective, relatively low-permeability supports minimize the negative impact of defects in the biomimetic layer, which are currently the main performance-limiting factor for biomimetic membranes. In particular, RO membranes as support layers would enable >99.85% salt rejection at ∼10000-fold greater biomimetic-layer defect area than for porous supports. By fundamentally characterizing neutral-solute permeation through RO and NF membranes, we show that RO membranes as support layers would enable high rejection of organic pollutants based on molecular size, overcoming the rapid permeation of hydrophobic solutes through the biomimetic layer. A biomimetic membrane could also achieve exceptionally high boron rejections of ∼99.7%, even with 1% defect area in the biomimetic layer. We conclude by discussing the implications of our findings for biomimetic membrane design.
AB - Reverse osmosis (RO) has become a premier technology for desalination and water purification. The need for increased selectivity has incentivized research into novel membranes, such as biomimetic membranes that incorporate the perfectly selective biological water channel aquaporin or synthetic water channels like carbon nanotubes. In this study, we consider the performance of composite biomimetic membranes by projecting water permeability, salt rejection, and neutral-solute retention based on the permeabilities of the individual components, particularly the water channel, the amphiphilic bilayer matrix, and potential support layers that include polymeric RO, nanofiltration (NF), and porous ultrafiltration membranes. We find that the support layer will be crucial in the overall performance. Selective, relatively low-permeability supports minimize the negative impact of defects in the biomimetic layer, which are currently the main performance-limiting factor for biomimetic membranes. In particular, RO membranes as support layers would enable >99.85% salt rejection at ∼10000-fold greater biomimetic-layer defect area than for porous supports. By fundamentally characterizing neutral-solute permeation through RO and NF membranes, we show that RO membranes as support layers would enable high rejection of organic pollutants based on molecular size, overcoming the rapid permeation of hydrophobic solutes through the biomimetic layer. A biomimetic membrane could also achieve exceptionally high boron rejections of ∼99.7%, even with 1% defect area in the biomimetic layer. We conclude by discussing the implications of our findings for biomimetic membrane design.
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U2 - 10.1021/acs.est.8b03426
DO - 10.1021/acs.est.8b03426
M3 - Article
C2 - 30106285
AN - SCOPUS:85052289622
SN - 0013-936X
VL - 52
SP - 10737
EP - 10747
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 18
ER -