A permeable fluorinated membrane that can selectively filter carbon dioxide out of flue gas at the point of release has been fabricated by researchers from the U.S. Department of Energy’s Oak Ridge National Laboratory and the University of Tennessee.

The inclusion of a unique fluorine-based polymer during synthesis results in a membrane that optimizes selectivity and permeability and exceeds the Robeson upper limit defining tradeoffs and constraints between Low-cost gas membranes were designed to remove carbon dioxide from industrial emissions. Source: Zhenzhen Yang/University of Tennesseethese two parameters. The material is carbonized by heating to impart a porous structure while maintaining the fluorinated constituents, which boost its selectivity for CO₂.

The CO₂ separation performance of the high surface area material rises significantly with the fluorine content in the membrane. Excellent thermal stability under air and CO₂ permeability and CO₂ to nitrogen gas selectivity were demonstrated.

This use of abundant, low-cost fluorine expands options for carbon-capture membranes and opens new directions for developing fluorinated membranes with other task-specific functionalities. Research on the CO₂ capture mechanisms of the membrane will continue in order to enhance emission control functionality.