Biomimetic membranes for water remediation applications are gaining much attention because of their high permeability and water selectivity. This research explores Lyotropic liquid crystals (LLC) as an active layer for Forward Osmosis membranes. LLC’s are lipid-based networks that are self-organizing, can conform to an array of geometries, exhibit high pore d<u>ensity,</u> can stabilize and incorporate enzymes and provide natural water channels which are readily tuneable in size. Current work has focused on characterization and assessing the efficiency of PAN/PVC membranes modified with LLC composed of Monoolein and Phosphocholines. Moreover, urease was used as a model enzyme to assess membranes capacity for small contaminant degradation. Membranes were tested in a Forward Osmosis system using NaCl 5% as an osmotic agent, Urea 1.3%, and NP water as feed solution. All membranes presented a water flux over 8 LMH for both feed solutions. Nonetheless, when using urea as a feed solution, a water flux increase was observed. Characterization of the membranes was carried out using a scanning electron microscope (SEM), where images of the active layer present a homogenous deposition of the LLC. The transversal cut shows the presence of sponge-like pores in the polymer mixture support. Contact angle (CA) assessment showed that all membranes were highly hydrophilic. Moreover, Brunauer–Emmett–Teller (BET) was used to determine pore size, which showed significant pore distribution and density variation, membranes with the incorporated enzyme have slightly larger pores. Additionally, the enzyme has been shown to remain active even while incorporated in the LLC layer. Achievement of the desired selectivity and specificity could lead to more cost-effective water remediation systems.

Using lyotropic liquid crystals with model enzyme as osmosis membrane modifiers

ACS Spring 2022

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