Skip to content

Ionic Liquid-based Composite Membranes Using Functional Crosslinkers

Patented low energy membrane to efficiently remove CO2 from gas streams

Published: 22nd June 2022
Ionic Liquid-based Composite Membranes Using Functional Crosslinkers


The global demand for natural gas is growing, as is the demand for technologies that can improve extracted gas to pipeline grade product. In 2015, the U.S. alone consumed over 24 million standard cubic feet of natural gas, and global natural gas production that year increased by 2.2% from 2014. However, untreated natural gas streams additionally contain carbon dioxide (CO2). Aside from the obvious environmental impacts, the inclusion of CO2 can lead to pipeline corrosion and have an effect on overall heating value of the gas product as well.

Currently, the predominant methods of CO2 removal are amine scrubbing and cryogenic distillation. These methods are energy intensive and amine scrubbing in particular, has negative environmental impacts. Separation membranes however offer an approach that can be incorporated at the well head (before the gas enters the pipeline) and passively separate CO2. These membranes may also be used in flues to scrub CO2 from emitted gases. They also require less maintenance and may be simply replaced when necessary.

Thus, separation membranes with increased gas selectivity and permeability and with an increased longevity are critical to gas production.

Technology Overview

Mixed-matrix membranes (MMMs) are separation membranes composed of a dispersed phase combined with a polymer matrix. MMMs maintain the superior separatory efficiency of the dispersed phase while taking advantage of the relative ease of processing associated with the polymer matrix. While the dispersant phase of the MMM is often a porous, highly selective material (e.g., zeolites, metal-organic frameworks, et.), they have less favorable adhesion properties both at the membrane and dispersant interfaces. Thus, interfacial voids, chain rigidification, and pore plugging can all contribute to reduced MMM performance. There is thus a need in the art for novel materials and methods for performing gas-gas separation. The new membrane material presented here provides zeolite-free poly(ionic liquid) (PIL)-ionic liquid (IL) polymers and membranes crosslinked with an ionic liquid crosslinking agent. Therefore, this membrane retains the advantages of high selectivity and permeability, but is also more robust with a longer lifecycle to replacement.

Stage of Development

Technology Readiness Level (TRL): 4.

  • Low energy membrane is patented
IP Status
  • Patented