Green Polymeric Membrane Fabrication Using Ionic Liquids
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Solution Overview
Problem
The use of conventional solvents like DMF, NMP, and DMAc in membrane fabrication is becoming restricted due to their toxicity, leading to challenges in producing membranes that are both environmentally friendly and effective.
Innovation Solution
The development of membrane fabrication methods using ionic liquids, such as [EMIM]DEP, which completely dissolve polymers like PES, allowing for the creation of membranes without volatile solvents, thereby avoiding the use of hazardous chemicals and enabling the continuation of membrane production even if conventional solvents are banned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solvents (DMF, NMP, DMAc) are used for membrane fabrication, then membranes can be produced with good mechanical properties and uniform pore sizes, but the process becomes harmful to human health and the environment due to toxicity
Solution Approach 1:
The patent changes the chemical parameter of the solvent from conventional toxic solvents (DMF, NMP, DMAc) to ionic liquids, which have different chemical properties including lower volatility and reduced toxicity, thereby resolving the contradiction between ease of manufacture and harmful factors
Solution Approach 2:
The patent employs ionic liquids as replaceable solvents that can be used in the membrane fabrication process without causing long-term environmental harm, allowing the process to continue even if conventional solvents are banned
2Productivity
If conventional solvents are used, then membrane production can continue with established processes, but the solvents may soon be withdrawn from the market due to high toxicity
Solution Approach 1:
The patent performs preliminary action by switching to ionic liquids before conventional solvents are completely withdrawn from the market, ensuring continuous membrane production capability and avoiding future disruptions
Solution Approach 2:
The patent uses ionic liquids as a universal solvent that can dissolve various polymers (PSf, PES, PAN, PVDF, extem) for membrane fabrication, providing multi-functionality that maintains productivity across different membrane types even as conventional solvents become unavailable
3Object-affected harmful factors
If ionic liquids are used instead of conventional solvents, then environmental friendliness is improved and solvents can be recovered for reuse, but the fabrication process requires new methods and conditions
Solution Approach 1:
The patent implements solvent recovery by discarding the used ionic liquid from the membrane fabrication process and recovering it for reuse, thereby improving environmental friendliness and reducing waste while maintaining process 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
This method results in membranes with improved mechanical properties, uniform pore sizes, and enhanced water permeance, capable of rejecting a wider range of molecular sizes, while also being environmentally friendly and allowing for the recovery of the ionic liquid for reuse.
Implementation Method 1
ionic liquids, such as [EMIM]DEP, which completely dissolve polymers like PES
Implementation Method 2
capable of rejecting a wider range of molecular sizes
Data Source
AI summary
Provided herein are methods of fabricating membranes using polymers with functionalized groups such as sulfone (e.g., PSf and PES), ether (e.g., PES), acrylonitrile (e.g., PAN), fluoride (e.g., pvdf and other fluoropolymers), and imide (e.g., extem) and ionic liquids. Also provided are membranes made by the provided methods.