Non-cross-linked PVAm Gas Separation Membrane
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas separation membranes face challenges such as degradation, poor permeance, and selectivity due to issues like evaporation, deactivation of carriers, and pore blockages, particularly when using high molecular weight cut-off supports, which limit their efficiency and application in separating carbon dioxide from gas mixtures.
Innovation Solution
The development of a membrane using non-cross-linked polyvinylamine (PVAm) with a molecular weight of at least 50,000, supported on high molecular weight cut-off substrates, and subjected to thermal treatment, which enhances permeance and selectivity without the need for external cross-linking agents, and the use of a carbon dioxide permeable layer for increased mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-linked PVAm membranes are used to prevent degradation, then stability is improved, but permeance decreases due to pore blockages
Solution Approach 1:
The patent removes the cross-linking step entirely from the membrane preparation process. By using PVAm with sufficiently high molecular weight (Mw ≥ 50,000) and avoiding cross-linking agents, the invention eliminates the source of pore blockages while maintaining membrane stability through the inherent properties of the high molecular weight polymer.
Solution Approach 2:
The patent changes the molecular weight parameter of the PVAm polymer to be at least 50,000, which fundamentally alters the membrane's behavior. This parameter change provides sufficient chain entanglement and mechanical strength to maintain stability without cross-linking, while preventing the pore blockage issues that arise from cross-linked structures.
2Productivity
If high molecular weight cut-off supports are used to increase permeance, then gas flow increases, but pore blockages occur reducing selectivity
Solution Approach 1:
The high molecular weight PVAm acts as an intermediary layer on the support membrane. It provides a selective separation function while allowing high gas permeance through its facilitated transport mechanism, eliminating the need for physical pore structures that would block at high MWCO values.
Solution Approach 2:
The patent replaces the mechanical pore-based separation mechanism with a chemical facilitated transport mechanism. Instead of relying on physical pore sizes to separate gases, the PVAm uses chemical interactions (CO2 binding to amine groups) to achieve separation, enabling high permeance without pore blockages.
3Reliability
If facilitated transport carriers are used to improve selectivity, then separation efficiency increases, but evaporation and deactivation occur
Solution Approach 1:
The PVAm polymer serves its own dual function: it provides both the structural matrix and the facilitated transport capability through its amine groups. This eliminates the need for separate mobile carrier molecules that would evaporate or deactivate, as the transport function is inherently built into the polymer structure itself.
Solution Approach 2:
The invention creates a composite structure where the PVAm polymer combines mechanical support functions with chemical transport functions in a single material system. This integrated approach eliminates the instability issues of multi-component systems with mobile carriers.
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
This approach results in membranes with excellent separation properties, stability, and high permeance, capable of handling high pressures without permeance or selectivity reduction, effectively addressing the limitations of previous membrane technologies.
Implementation Method 1
One option for membrane separation is the use of a facilitated transport membrane, also known as a supported liquid membrane (SLM) with mobile facilitated transport carriers
Implementation Method 2
thermal treatment of the formed membrane can be beneficial to the permeance and selectivity of the membrane
Implementation Method 3
Membrane technology is such a new separation technique: Membrane modules also significantly reduce weight and space requirements of separation equipment
Data Source
AI summary
A membrane suitable for separating a gas from a gas mixture comprising a non cross-linked PVAm having a molecular weight of at least Mw 100,000 carried on a support wherein after casting onto the support, said PVAm has been heated to a temperature in the range 50 to 150° C., e.g. 80 to 120° C.