CO2-Selective Gas Separation Membrane With Siloxane Substituent Tuning
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Solution Overview
Problem
Existing gas selective permeable composite membranes, such as those made of organosiloxane compounds, face challenges in achieving high gas separability of carbon dioxide against nitrogen and gas permeability.
Innovation Solution
A gas separation membrane comprising a first layer made of organopolysiloxane and a second layer of a polydimethylsiloxane derivative with a specific molecular descriptor αMOL, calculated based on Formulas (1) and (2), where αMOL < 0, to enhance carbon dioxide permeability and separability against nitrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas selective permeable composite membrane is made using organosiloxane compounds, then the membrane structure is formed, but the gas separability of carbon dioxide to nitrogen and gas permeability of carbon dioxide are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the siloxane compound by introducing specific substituents (fluorine atoms, aromatic rings, or heteroatoms) to achieve optimal balance between gas separability and permeability. This parameter optimization resolves the contradiction by modifying molecular structure to enhance both separation performance and gas transport capability
Solution Approach 2:
The patent creates a composite membrane structure combining organopolysiloxane base material with modified siloxane compounds containing specific functional groups. This composite approach integrates the advantages of both materials to achieve high carbon dioxide separability while maintaining excellent permeability, resolving the technical contradiction between separation and productivity
2Strength
If the thickness of the thin membrane is increased, then the mechanical strength is improved, but the gas permeability of carbon dioxide decreases
Solution Approach 1:
The patent optimizes the thickness parameter of the thin membrane to a specific range (1-30 μm) and combines it with modified siloxane compound composition to achieve both mechanical strength and high gas permeability. This parameter optimization resolves the contradiction by finding the optimal balance point between structural integrity and transport efficiency
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 improved gas separability of carbon dioxide against nitrogen with maintained gas permeability, suitable for carbon dioxide recovery and purification from mixed gases.
Implementation Method 1
a gas separation membrane that selectively separates carbon dioxide from a mixed gas containing the carbon dioxide and nitrogen by allowing the carbon dioxide to permeate
Data Source
AI summary
Provided is a gas separation membrane that selectively separates carbon dioxide from a mixed gas by allowing the carbon dioxide to permeate. The gas separation membrane includes: a thin film made of a polydimethylsiloxane derivative that includes a main chain formed of a siloxane bond and a methyl group bonded to silicon atoms contained in the siloxane bond, with a part of the methyl group being substituted with a substituent X. A molecular descriptor αMOL of the substituent X calculated based on the following Formulae (1) and (2) satisfies the following Formula (3).αMOL=∑iNαAi(1)[In the above Formula (1), i is a natural number that changes from 1 to N. N is the number of atoms excluding hydrogen atoms contained in the substituent X.]αAi=rAirC-1(2)[In the above Formula (2), rAi is a covalent bond distance of atoms excluding the hydrogen atoms contained in the substituent X. rC is the covalent bond distance of an sp3 orbital of the carbon atoms.]αMOL<0(3)