MSE Colloquium: Rohit Karnik, MIT

3:00 pm on Friday, October 4, 2013
4:00 pm on Friday, October 4, 2013
8 St. Mary’s Street, Room 901
Abstract: Advances in membrane technology are largely driven by improvements in membrane materials and understanding of their transport properties. In this talk, I will discuss our recent work on two types of nanostructured membranes for water purification and gas separations. The first class of membranes for water desalination employs short hydrophobic nanopores that allow for transport via nearly isothermal evaporation and condensation between two menisci separated by sub-micrometer gaps. This design combines the advantages of thermal processes and reverse osmosis and has the potential for enhanced flux and resistance to anti-biofouling agents. The second class of membranes uses porous graphene as the selective material. Transport measurements have elucidated the role of intrinsic defects that allow for partially selective transport of molecules through graphene. We have also developed methods to create tunable, sub-nanometer pores in graphene using a nucleation and growth process and demonstrated that the process enables us to tune the selectivity of macroscopic graphene membranes. I will also discuss our progress towards further development of these membranes for separation of gases and small molecules/ions, which requires strategies to mitigate the effect of flow through intrinsic defects. These membranes have potential applications in a variety of filtration processes and gas separations with enhanced flux and tunable transport properties that are not be easily accessible in other membrane materials.