Development of ultrafast organic solvent nanofiltration with turbostratic nanoporous carbon sheet membrane

Abstract

Development of ultrafast and selective nanofiltration membranes for viscous green solvents, such as isopropyl alcohol (IPA), is a big challenge in the fine chemical, food, and pharmaceutical industries. However, all existing nanofiltration membranes, including polymers, have been critically limited by low solvent permeance and low selectivity for solute molecules with a nanoscale feature dimension. This might be attributed to narrow channel structures and strong interaction between membrane materials and viscous green solvents. Herein, we significantly enhanced the nanofiltration performance with IPA by using turbostratic nanoporous carbon sheet membrane. Sharp separation of viscous alcohol and molecules smaller than 600 Da from larger molecules (molecular weight cut-off: 600 Da) was achieved by using the developed membrane with ultrafast IPA permeance of ~1800 L m-2 h-1 bar-1. The membrane performance far exceeds the upper bound of exiting nanofiltration membranes, as reflected by the IPA permeance being two orders greater than those for commercially available membranes, sustaining high rejection rates for sub-nanometer size molecules.