Ionic Liquid Polysulfone Membranes for Stable CO2 Capture

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Solution Overview

Problem

Existing ionic liquid polymeric membranes for CO2 capture suffer from mechanical instability and inefficiency, particularly due to ionic liquid leaching at low pressure differentials, limiting their application in photoelectrocatalysis and other gas separation processes.

Innovation Solution

A polymeric membrane is developed by combining ionic liquid functionalized polysulfone with unmodified polysulfone in specific ratios, forming a mechanically stable and efficient membrane for CO2 capture, utilizing a blend of ionic liquids with specific cations and anions chemically bonded into the polysulfone side chains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ionic liquid is embedded within polysulfone matrix to enhance CO2 capture efficiency, then CO2 sorption efficiency is improved, but mechanical stability deteriorates due to ionic liquid leaching at low pressure differential

Engineering Contradiction:

ImproveCO2 capture efficiencyVSAvoidmechanical stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent creates a composite membrane system combining polysulfone matrix with ionic liquid functional groups chemically bonded to side chains. This composite structure integrates the CO2 capture capability of ionic liquids with the mechanical stability of polysulfone, resolving the contradiction between capture efficiency and mechanical stability by forming a unified material system where each component complements the other's strengths.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The ionic liquid functional groups are introduced specifically at the side chains of the polysulfone polymer rather than uniformly throughout the bulk material. This localized functionalization allows the membrane to exhibit CO2 capture properties at the molecular level while maintaining the overall structural integrity and mechanical stability of the polysulfone matrix, thus achieving both high CO2 sorption efficiency and mechanical stability.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If ionic liquid functional groups are introduced into polysulfone side chains to improve CO2 capture, then CO2 solubility is enhanced, but mechanical consistency deteriorates

Engineering Contradiction:

ImproveCO2 solubilityVSAvoidmechanical consistency

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent introduces ionic liquid functional groups at specific side chain positions of the polysulfone polymer rather than modifying the entire polymer structure uniformly. This localized modification enhances CO2 solubility through the ionic liquid's high affinity for CO2 molecules while preserving the mechanical consistency of the main polysulfone matrix, as the bulk polymer structure remains intact.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the chemical parameters of the polysulfone by introducing ionic liquid functional groups with specific cations and anions that have high CO2 solubility. This parameter change at the molecular level increases CO2 uptake capacity while the overall polymer architecture and mechanical properties are maintained through controlled functionalization degree and selection of ionic liquid components.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The membrane achieves high CO2 capture efficiency with improved mechanical stability, addressing previous mechanical inconsistencies and enhancing gas separation capabilities.

Implementation Method 1

Previous studies have demonstrated positive sorption results with the method of embedding Supported Ionic Liquids (SILs) within a polysulfone (PSF) polymeric matrix for CO2 capture

Methodology Applied

Scientific EffectSorption: Sorption

Implementation Method 2

the membrane achieves high CO2 capture efficiency with improved mechanical stability, addressing previous mechanical inconsistencies and enhancing gas separation capabilities

Methodology Applied

Scientific EffectSolubility: Solvation

Implementation Method 3

a polymeric membrane comprising: a) an ionic liquid of formula [A][X]... b) a combination of unmodified polysulfone and a modified polysulfone

Methodology Applied

Scientific EffectPermeation: Permeation

Data Source

PatentEP4613365A1Membranes with ionic liquids for co2 capture and devices for gas separation comprising them

Publication Date: 2025.09.10 FUNDACIO EURECAT

Figure 1

AI summary

It relates to polymeric membranes and devices comprising them, useful for CO2 capture, the membrane comprising: a) an ionic liquid; and b) a combination of unmodified polysulfone and a modified polysulfone in a weight ratio from 10:1 to 1:1; where the modified polysulfone is a polysulfone functionalized with at least a cation of an ionic liquid chemically bonded into a side chain of the polysulfone; as well as to a process for capturing CO2 comprising contacting an initial gas mixture comprising carbon dioxide in a concentration up to 80% by weight with the polymeric membrane under conditions such as to obtain a gas product which has a higher weight percentage of CO2 than the original gas mixture and permeates through the membrane.