nanoporous rgo membranes for separation …deshpande.mit.edu/files/assets/shreya is15...

Nanoporous rGO membranes for separation applications!Ideastream 2015!Shreya Dave, David Cohen-Tanugi, Li-Chiang Lin, Brendan Smith, Nicola Ferralis, Jeffrey Grossman !

http://www.theatlantic.com/photo/2015/04/the-american-west-dries-up/389432/!

Tampa Bay Desalination Plant

Polymer membranes are used for Reverse Osmosis desalination

In practice, cost is high.

•  resilience to cleaning agents •  tendency to biofoul

•  permeability (flow rate) •  lifetime

•  cost competitive

Membrane performance is inherently limited.

Computational work has identified a unique design space for reduced graphene oxide (rGO).

oxidation!

Graphene oxide (GO) is a more scalable feedstock.

CVD Graphene! Graphene Oxide!

Solution processable! ✗ ✓

Energy inputs ! ✗ 1000 C ✗ vacuum

✓ 150 C ✓ atmosphere

Consumables ! ✗ copper substrate ✗ strong oxidizers (✓ “greener” chemicals)

Sheet size! ✓ inches ✗ 0.5 - 5 um

Yield (laboratory)! ✗ 1x10-6 g/2 hrs !

✓ 200 g/2 hrs

Cost (current retail)! ✗ $80x106/g ✓ $300/g

reduction!

increasing functional groups!

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Defects are created in reduced graphene oxide (rGO). SEM micrograph of GO

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e Surface amorphous carbon alters GO’s structural integrity, surface chemistry, and properties.

TEM studies reveal carbon lattice structure.

Preliminary results suggest that rGO is more stable than GO when exposed to water.!

DI water No treatment

Applications beyond municipal desalination hold promise.

•  Harsh chemical environments •  High or low temperature separation

applications •  High fouling feed sources