Polyamide TFC Reverse Osmosis Membrane Post-Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyamide TFC reverse osmosis membranes struggle to simultaneously enhance both water permeability and salt rejection, with existing methods either improving one at the expense of the other or not achieving desired performance levels.
Innovation Solution
A preparation method involving interfacial polymerization followed by post-treatment with polyfunctional tertiary alcohol amine, which includes contacting the polyamide active layer with an aqueous solution containing 0.1 to 100 wt % of polyfunctional tertiary alcohol amine and subsequent high-temperature drying, to form a polyamide TFC reverse osmosis membrane with improved water permeability and salt rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interfacial polymerization is used to form polyamide active layer, then salt rejection is improved, but water permeability is limited
Solution Approach 1:
The patent applies preliminary action by immersing the membrane in a polyfunctional tertiary amine aqueous solution before the final polyamide layer formation. This pre-treatment modifies the support membrane surface and creates a foundation that enables subsequent formation of a polyamide layer with both high salt rejection and high water permeability, rather than relying solely on the interfacial polymerization parameters.
Solution Approach 2:
The patent changes chemical parameters by introducing polyfunctional tertiary amine compounds with specific functional groups into the aqueous phase. This chemical modification alters the surface properties and reactivity of the support membrane, enabling the formation of a polyamide active layer with optimized performance characteristics that simultaneously achieves high salt rejection and high water permeability.
2Productivity
If post-treatment with conventional amine solutions is applied, then water permeability is improved, but salt rejection deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using polyfunctional tertiary amine compounds with specific molecular structures and functional groups. This specific chemical parameter change allows the post-treatment to enhance water permeability while maintaining the salt rejection capability, unlike conventional amine solutions that compromise salt rejection.
Solution Approach 2:
The patent creates a composite structure by combining the polyamide active layer with a support membrane that has been modified by polyfunctional tertiary amine compounds. This composite approach allows the synergistic combination of materials with different properties, where the amine-modified support provides water permeability enhancement while the polyamide layer maintains salt rejection.
3Reliability
If multiple treatment steps are added to improve membrane performance, then manufacturing complexity increases
Solution Approach 1:
The patent merges the support membrane modification and polyamide layer formation steps into an integrated process. The polyfunctional tertiary amine treatment of the support membrane and the subsequent interfacial polymerization are combined in a sequential manner that simplifies the overall manufacturing process while achieving superior membrane performance, rather than treating them as separate independent steps.
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 results in a polyamide TFC reverse osmosis membrane with water permeability exceeding 70 L/m2hr and salt rejection greater than 95%, outperforming prior art in both parameters.
Implementation Method 1
a polyamide active layer is formed through an interfacial polymerization reaction occurring between polyfunctional aromatic amine monomer having at least two primary amine groups and polyfunctional acyl halide monomer having at least three acyl halide groups
Implementation Method 2
A TFC reverse osmosis membrane is essentially used in desalination
Data Source
AI summary
A preparation method of a polyamide thin film composite reverse osmosis membrane and a polyamide thin film composite reverse osmosis membrane prepared using the preparation method are provided. The preparation method of a polyamide thin film composite reverse osmosis membrane using interfacial polymerization of an amine aqueous solution and amine-reactive compound includes the steps of (a) forming an active layer through interfacial polymerization by contacting a surface of a porous support with an amine aqueous solution containing a polyfunctional aromatic amine monomer and an organic solution containing polyfunctional acyl halide monomer as an amine-reactive compound, and (b) performing post-treatment preceded by the forming of the active layer by contacting the active layer with an aqueous solution containing 0.1 to 100 wt % of polyfunctional tertiary alcohol amine. The polyamide thin film composite reverse osmosis membrane prepared by using the polyfunctional tertiary alcohol amine as a post-treatment compound has improved water permeability and salt rejection compared to a case of using various post-treatment agents or methods.