Filtration Membrane Stability at Extreme pH
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Solution Overview
Problem
Existing methods for producing filtration membranes with nanofiltration properties are technically complex and expensive, and the resulting membranes are not stable at extreme acidic pH values.
Innovation Solution
A method involving a textile composite coated with hydrophilized polyether sulfone, treated with an aqueous medium containing polyethylene glycol and an aliphatic alcohol, followed by drying, to produce a filtration membrane with an average molecular cut-off of less than 1000 g/mol, enhancing stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If interfacial polymerization is used to produce nanofiltration membranes, then nanofiltration properties are achieved, but the process becomes technically complex and expensive
Solution Approach 1:
The invention changes the fundamental production parameter from interfacial polymerization to a physical coating and drying process. The patent applies a solution containing polyethersulfone and polyethylene glycol to a support membrane, then dries it to form the nanofiltration layer. This parameter change eliminates the complexity of interfacial polymerization while achieving the desired nanofiltration separation performance with a molecular weight cut-off of less than 1000 g/mol.
2Manufacturing precision
If interfacial polymerization is used to produce nanofiltration membranes, then nanofiltration properties are achieved, but production costs increase
Solution Approach 1:
The invention changes the production method from costly interfacial polymerization to a simpler coating and drying process using readily available materials like polyethersulfone and polyethylene glycol. This parameter change significantly reduces production costs while maintaining nanofiltration performance, making the process more economically viable for industrial application.
3Manufacturing precision
If conventional nanofiltration membranes are produced, then separation performance is achieved, but stability at extreme acidic pH values is insufficient
Solution Approach 1:
The invention uses a composite material system consisting of polyethersulfone as the base polymer and polyethylene glycol as an additive in specific proportions. This composite formulation creates a nanofiltration membrane that achieves both the required molecular weight cut-off of less than 1000 g/mol and enhanced stability at extreme acidic pH values, overcoming the limitation of conventional nanofiltration membranes.
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 method produces filtration membranes with high salt rejection and stability at extreme pH values, reducing production costs and complexity, and achieving effective separation of molecules with a molar mass less than 1000 g/mol.
Implementation Method 1
a filtration membrane with an average molecular cut-off of < 1000 g/mol
Implementation Method 2
Filtration membranes are often hydrophilized to improve fouling properties or increase performance
Data Source
AI summary
The invention relates to a method for producing a filtration membrane having a mean molecular weight cut-off of < 1000 g/mol.