Polyamide Reverse Osmosis Membrane via Composite Amine Solution
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Solution Overview
Problem
Conventional polyamide reverse osmosis composite membranes fail to simultaneously enhance both water permeability and salt rejection rate to desired extents.
Innovation Solution
An amine aqueous solution containing alcohol amine and tertiary amine compounds is used for forming a polyamide active layer, followed by interfacial polymerization and post-treatment to create a membrane with a partial cross-linked interfacial structure, improving water permeability and salt rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyamide reverse osmosis composite membranes are used, then basic membrane structure is achieved, but water permeability and salt rejection rate cannot be simultaneously enhanced to desired extents
Solution Approach 1:
The patent changes the chemical composition parameters of the amine aqueous solution by adding tertiary amine compounds (such as triethylamine, tributylamine) to the conventional polyfunctional amine solution. This parameter modification enables the formation of a polyamide active layer with optimized molecular structure that simultaneously achieves high water permeability and high salt rejection rate, resolving the contradiction between these two performance parameters.
Solution Approach 2:
The patent creates a composite amine solution system combining polyfunctional amine compounds (MPD, TDA) with tertiary amine compounds (TEA, TBA). This composite approach allows the tertiary amine to act as a chain transfer agent during interfacial polymerization, creating a polyamide active layer with enhanced free volume and optimized pore structure, thereby achieving both high water flux and high salt rejection.
2Productivity
If polyamide active layer is formed by interfacial polymerization between polyfunctional amine and polyfunctional acyl halide, then membrane structure is created, but performance optimization is limited
Solution Approach 1:
The tertiary amine compound serves as an intermediary substance during the interfacial polymerization process. It acts as a chain transfer agent that mediates the reaction between polyfunctional amine and polyfunctional acyl halide, controlling the polymerization kinetics and molecular weight distribution of the polyamide active layer. This intermediary role enables better control over active layer formation while enhancing water flux performance.
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 resulting polyamide reverse osmosis composite membrane exhibits high water permeability and enhanced salt rejection rate, surpassing the performance of conventional methods.
Implementation Method 1
a polyamide active layer is formed by interfacial polymerization, which is reacted a polyfunctional amine with a polyfunctional acyl halide compounds
Implementation Method 2
A reverse osmosis composite membrane is essentially used in desalination
Data Source
Figure 1
AI summary
Disclosed are an amine aqueous solution for forming an active layer of a polyamide reverse osmosis composite membrane and a preparation method of the polyamide reverse osmosis composite membrane using the same. The amine aqueous solution comprises 0.1 to 20 wt % of a polyfunctional amine compound, 0.1 to 20 wt % of an alcohol amine compound, 0.1 to 20 wt % of a tertiary amine compound, and 40 to 99.7 wt % of water. Due to using an amine aqueous solution having an alcohol amine and a tertiary amine compound, the polyamide reverse osmosis composite membrane has high water permeability and enhanced salt rejection rate, and thus is useful for the membrane field.