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US-12617894-B2 - Polymer fiber screen surface modifications for cation exchange membranes

US12617894B2US 12617894 B2US12617894 B2US 12617894B2US-12617894-B2

Abstract

A sulfonated polymer fiber screen and a method for fabricating the same is disclosed. For example, a composition may include a plurality of sulfonated polymer fibers. The sulfonated polymer fibers may include polyether ether ketone (PEEK) fibers or polyaryl ether ketone (PAEK) fibers that are contacted with an acid bath that includes a sulfur containing group.

Inventors

  • Valerie M. Farrugia
  • Michael S. Hawkins

Assignees

  • Genesee Valley Innovations, LLC

Dates

Publication Date
20260505
Application Date
20220204

Claims (18)

  1. 1 . A composition, comprising: a plurality of sulfonated polymer fibers, wherein the plurality of sulfonated polymer fibers comprises sulfonated polyether ether ketone (PEEK) fibers or sulfonated polyaryl ether ketone (PAEK) fibers, wherein the plurality of sulfonated polymer fibers is created by contacting unsulfonated polyether ether ketone fibers or unsulfonated polyaryl ether ketone fibers with an acid bath comprising methane sulfonic acid, ethane sulfonic acid, sulfurous acid, or a combination thereof for between 2 to 5 seconds.
  2. 2 . The composition of claim 1 , wherein the sulfonated PEEK fibers have an average diameter of between 0.0015 inches and 0.0050 inches.
  3. 3 . The composition of claim 1 , wherein the sulfonated PEEK fibers are arranged in a screen with open spaces between the sulfonated PEEK fibers.
  4. 4 . The composition of claim 3 , wherein the screen comprises an open area of between 20 percent to 60 percent.
  5. 5 . The composition of claim 4 , wherein the screen comprises an open area of approximately 22 percent.
  6. 6 . An article, comprising: a sulfonated polymer selective barrier material, wherein the sulfonated polymer selective barrier material comprises sulfonated polyether ether ketone (PEEK) fibers or sulfonated polyaryl ether ketone (PAEK) fibers, wherein the sulfonated polymer selective barrier material is created by contacting unsulfonated polyether ether ketone fibers or unsulfonated polyaryl ether ketone fibers with an acid bath comprising methane sulfonic acid, ethane sulfonic acid, sulfurous acid, or a combination thereof for between 2 to 5 seconds.
  7. 7 . The article of claim 6 , wherein the sulfonated polymer selective barrier material has an ion exchange capacity of between about 0.10 to about 0.20 milliequivalents per gram (meq/g).
  8. 8 . A method, comprising: contacting an unsulfonated polymer selective barrier material with an acid bath comprising a sulfur containing group to sulfonate the unsulfonated polymer selective barrier material in a sulfonation reaction, wherein the unsulfonated polymer selective barrier material comprises polyether ether ketone (PEEK) fibers or polyaryl ether ketone (PAEK) fibers, and wherein the unsulfonated polymer selective barrier material is contacted with the acid bath comprising methane sulfonic acid, ethane sulfonic acid, sulfurous acid, or a combination thereof for between 2 to 5 seconds; and stopping the sulfonation reaction.
  9. 9 . The method of claim 8 , wherein the unsulfonated polymer selective barrier material is arranged as a cation exchange membrane with open spaces and contacted with the acid bath in-situ.
  10. 10 . The method of claim 9 , wherein the cation exchange membrane comprises an open area of between about 20 percent to about 60 percent.
  11. 11 . The method of claim 10 , wherein the cation exchange membrane comprises an open area of approximately 22 percent.
  12. 12 . The method of claim 8 , wherein the unsulfonated polymer selective barrier material comprises the polyether ether ketone (PEEK) fibers or the polyaryl ether ketone (PAEK) fibers having an average diameter of between 0.0015 inches and 0.0050 inches.
  13. 13 . The method of claim 12 , wherein the PEEK fibers or PAEK fibers have an average diameter of 0.0028 inches.
  14. 14 . The method of claim 8 , wherein the acid bath further comprises sulfuric acid.
  15. 15 . The method of claim 14 , wherein the sulfuric acid comprises greater than 80 percent concentration of sulfuric acid.
  16. 16 . The composition of claim 1 , wherein the unsulfonated polymer selective barrier material is contacted with the acid bath to tune an ion exchange capacity for use in a cation exchange membrane.
  17. 17 . The article of claim 6 , wherein the unsulfonated polymer selective barrier material is contacted with the acid bath to tune an ion exchange capacity for use in a cation exchange membrane.
  18. 18 . The method of claim 8 , wherein the unsulfonated polymer selective barrier material is contacted with the acid bath to tune an ion exchange capacity for use in a cation exchange membrane.

Description

The present disclosure relates generally to membrane electrode assemblies and relates more particularly to polymer fiber screens for gas diffusion electrodes used in various conversion systems. BACKGROUND The emission of greenhouse gases (GHGs) like CO2 is causing depletion of the earth's ozone layer and the global temperature increase, leading to adverse effects on human health, agriculture, and water resources. To mitigate global climate change, worldwide interest has been focused onto the field of CO2 capture and utilization (CCU), where electro-catalytic conversion of CO2 into value-added chemicals and synthetic fuels is one of the attractive approaches. With appropriate electro-catalysts and reaction conditions including overpotential, reaction temperature, and electrolyte, etc., CO2 can be electrochemically converted into various products such as carbon monoxide (CO), methane (CH4), ethylene (C2H4), formic acid (HCOOH), methanol (CH3OH) and ethanol (C2H5OH), etc. At the current stage, electrochemical conversion of CO2 into CO is one of the most promising reactions, due to its high technological and economic feasibility. In this reaction, syngas (CO and H2) can be generated in an energy-efficient way and then used as feedstocks to produce synthetic hydrocarbons via Fischer-Tropsch synthesis process. SUMMARY According to aspects illustrated herein, there is provided a sulfonated polymer fiber screen and a method for fabricating the sulfonated polymer fiber screen. One disclosed feature of the embodiments is a composition comprising a plurality of sulfonated polymer fibers. Another disclosed feature of the embodiments is an article comprising a screen comprising a plurality of sulfonated polymer fibers. Another disclosed feature of the embodiments is a method to fabricate a sulfonated polymer fiber screen. The method comprises contacting a plurality of unsulfonated polymer fibers with an acid comprising a sulfur containing group to sulfonate the plurality of unsulfonated polymer fibers in a sulfonation reaction and stopping the sulfonation reaction. BRIEF DESCRIPTION OF THE DRAWINGS The teaching of the present disclosure can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an exploded block diagram of an example cation exchange assembly with a SPEEK screen of the present disclosure; FIG. 2 illustrates example chemical structural formulas of the sulfonation of PEEK to SPEEK of the present disclosure; FIG. 3 illustrates an example process flow of the sulfonation of PEEK to SPEEK of the present disclosure; FIG. 4 illustrates an example of fiber of the PEEK screen and an illustration of a diameter dimension of the present disclosure; FIG. 5 illustrates an example PEEK screen and an illustration to define average porosity; FIG. 6 illustrates an example PEEK screen with fibers having a first diameter and a first sized opening of the present disclosure; FIG. 7 illustrates an example PEEK screen with fibers having a second diameter and the first sized opening of the present disclosure; FIG. 8 illustrates example contact angles of water droplets to a PEEK screen and a SPEEK screen of the present disclosure; FIGS. 9A-9B illustrates example SEM images of various PEEK screens before and after sulfonation of the present disclosure; and FIG. 10 illustrates an example flowchart of a method for fabricating the sulfonated polymer screens of the present disclosure. To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. DETAILED DESCRIPTION The present disclosure broadly discloses a sulfonated poly(ether ether ketone) screen surface for cation exchange membranes and a method for producing the same. Cation exchange membranes can be used for electro-catalytic conversion of CO2 into value-added chemicals and synthetic fuels. However, cation exchange membranes can be used for other applications as well, such as fuel cells, sewage disposal, sea water desalination, electrodialysis, chemical catalysis, gas separation, and the like. Current cation exchange membranes can be fabricated from poly(ether ether ketone) (PEEK). PEEK is a high performance engineering thermoplastic that is known for its superb mechanical properties, good solvent resistance, and high thermo-oxidative stability. PEEK by itself though is highly hydrophobic and causes water droplets to have a very large contact angle. As a result, PEEK screens can be inefficient for passing water throughout the screen for cation exchange membranes. One solution is to use an ionomer material called Nafion. However, Nafion is considered to be a high cost material that is not environmentally friendly. The present disclosure provides a sulfonated PEEK (SPEEK) screen that performs as well as Nafion, but is much cheaper to produce and is more environmentally friendly than Nafion. The SPEE