COF-PEBAX Membrane for High-Selectivity CO2 Separation

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Solution Overview

Problem

Existing polymeric membranes for CO2 separation face a trade-off between gas permeability and selectivity, constrained by the Robeson upper bound, and suffer from compatibility issues with inorganic fillers leading to defects and voids in mixed matrix membranes (MMMs).

Innovation Solution

A mixed-matrix membrane (MMM) using a covalent organic framework (COF) filler, such as COF-316, dispersed in a poly(ether-block-amide) (PEBAX) matrix, with specific structural and compositional characteristics to enhance CO2 separation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polymeric membranes are used for CO2 separation, then the membrane structure is simple and easy to manufacture, but the gas permeability and selectivity are constrained by the Robeson upper bound

Engineering Contradiction:

Improvemembrane manufacturing simplicityVSAvoidCO2 separation efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent employs mixed matrix membranes (MMMs) that combine polymeric materials with porous fillers (such as metal-organic frameworks, covalent organic frameworks, or zeolites) to create a composite structure. This composite approach allows the membrane to simultaneously maintain ease of manufacture from the polymer matrix while achieving enhanced CO2 permeability and selectivity through the incorporated porous fillers, thereby surpassing the Robeson upper bound limitation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent incorporates porous filler materials with specific pore sizes and structures into the polymeric membrane matrix. These porous materials provide additional transport pathways for CO2 molecules while maintaining structural integrity, enabling the membrane to achieve both high CO2 permeability and selectivity without compromising manufacturing simplicity.

Inventive Principle:

Principle #31Porous materials

2Productivity

If inorganic fillers are added to polymeric membranes to improve CO2 separation, then gas permeability and selectivity increase, but compatibility issues cause defects and voids in the membrane structure

Engineering Contradiction:

ImproveCO2 separation performanceVSAvoidmembrane structural integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses surface modification techniques and coupling agents as intermediaries between the polymeric matrix and inorganic filler particles. These intermediaries improve the interfacial compatibility and adhesion between the filler and polymer, preventing defects and voids while maintaining the enhanced CO2 separation performance provided by the filler materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes various parameters including filler particle size distribution, filler loading concentration, and surface treatment conditions to maximize compatibility between the polymeric matrix and inorganic fillers. By carefully controlling these parameters, the membrane achieves both high CO2 separation performance and structural integrity without defects.

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 COF-316/PEBAX MMM exhibits increased CO2 permeability and selectivity over other gases, surpassing the Robeson upper bound, with CO2/N2 selectivity up to 5 times higher and permeability up to 5 times greater than without the COF, while maintaining homogeneous dispersion and stability.

Implementation Method 1

the molecular sieving function of 2D nanomaterials can have an impact on applications involving gas separation

Methodology Applied

Scientific EffectMolecular sieving: Molecular Sieve

Implementation Method 2

Tuning of intrinsic pores can modify the physiochemical properties and facilitate the gas transport properties of the MMMs

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

2D nanomaterials offer additional advantages, such as atomic-level thickness, the presence of small intrinsic pores, and interlayer channels

Methodology Applied

Scientific EffectPorosity: Porosity

Implementation Method 4

facilitate the gas transport properties of the MMMs

Methodology Applied

Scientific EffectPermeation: Permeation

Data Source

PatentUS20260007996A1Method for separating carbon dioxide from a gas mixture

Publication Date: 2026.01.08 KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS

AI summary

A method of separating a gas mixture, including contacting the gas mixture with a membrane and passing a portion of the gas mixture through the membrane. The portion of the gas mixture that passes through the membrane includes carbon dioxide. The membrane includes a poly (ether-block-amide) (PEBAX) and a covalent organic framework (COF). The COF is an optionally substituted COF-316 and the COF is dispersed in a matrix of the PEBAX to form the membrane. The membrane includes 0.1-5 wt. % of the COF relative to a total weight of the membrane.