(380w) Electrospray 3D Printing to Unlock Customized Membrane Performance

Polyamide membranes have for 40 years dominated the membrane-based desalination field. Interfacial polymerization enabled the manufacturing of polyamide reverse osmosis (RO) and nanofiltration (NF) membranes at scale. Remarkably, little has changed in the materials or the manufacturing approaches chosen to fabricate these membranes since their invention in the early 1980s.

An emerging membrane manufacturing method, electrospray printing, has been shown to be able to fabricate both NF and RO membranes. This process uses high strength electric fields to generate atomized sprays of solvents that carry and distribute monomers homogenously directly onto the support where they subsequently react to form polyamide. This method allows for exquisite control of membrane thickness and chemistry.

Thickness control is possible by adjusting the concentration of the monomer and the number of deposited layers of polymer on the substrate. Chemistry can be adjusted by changing the monomer. This work demonstrates the ability to produce membrane of different thickness and chemistry and to use those control levers to customize membrane properties across a wide range of permeance and selectivity. In particular, we demonstrate that blending monomers results in producing membranes between current commercial NF and RO performance levels.

We also report the effects of amine to acyl chloride ratio on membrane performance to achieve a better understanding of reaction. We also report the membrane yield (i.e. the percentage of membrane tested that were “successful”) which is highly dependent on the membrane thickness to assess the applicability of the method at various levels of membrane thickness.

We discuss all these results in the context of membrane processes that could benefit from the ability to “dial in” membrane properties for improved desalination treatment train performance.