Water Permeable Membranes Using Reactive Additives
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Solution Overview
Problem
Existing water permeable membranes for reverse osmosis lack sufficient salt rejection and water flux, limiting their effectiveness in desalination and other applications.
Innovation Solution
Development of water permeable membranes incorporating a hydrophilic and reactive additive during the interfacial polymerization of aromatic or aromatic/aliphatic polyamides on a porous support, enhancing salt rejection and flux rates by chemically bonding the additive to the polyamide, thereby improving the membrane's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-linked aromatic polyamide membranes are used for reverse osmosis, then salt rejection and water flux are achieved, but the performance is insufficient and cannot meet the desired high flux and high salt rejection criteria
Solution Approach 1:
The patent modifies the chemical composition parameters of the membrane by incorporating hydrophilic additives (such as polyethylene glycol, polyvinyl alcohol, or carboxymethyl cellulose) into the polyamide matrix. This changes the physical and chemical properties of the membrane, increasing hydrophilicity and creating more water pathways, thereby simultaneously improving both salt rejection and water flux performance
Solution Approach 2:
The patent creates a composite membrane structure by combining conventional cross-linked aromatic polyamide with hydrophilic additives. The composite material integrates the high salt rejection capability of polyamide with the high water affinity and conductivity of hydrophilic substances, achieving synergistic improvement in both salt rejection and water flux
2Productivity
If conventional water permeable membranes are used, then basic separation function is provided, but the flux rate and salt rejection are not sufficient for effective desalination
Solution Approach 1:
The patent changes the hydrophilicity parameter of the membrane by adding hydrophilic substances, which increases water flux while maintaining or enhancing salt rejection through the modified membrane structure
Solution Approach 2:
The hydrophilic additives act as intermediaries that facilitate water transport through the membrane while the polyamide matrix continues to provide the selective barrier for salt rejection. The intermediary substances create additional water pathways without compromising the rejection mechanism
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 membranes exhibit a salt rejection capability of at least 98% and a flux rate of at least 34 gfd when tested with a 2000 ppm NaCl solution at 225 psi, significantly improving upon existing membrane technologies.
Implementation Method 1
a membrane formed from a cross-linked aromatic or aromatic/aliphatic polyamide interfacially polymerized on a porous support
Implementation Method 2
dissolved substances such as salts can be separated from their solvents, e.g. water, by a procedure known as reverse osmosis
Data Source
AI summary
Water permeable membranes and methods of forming water permeable membranes are provided. The water permeable membranes are comprised of a cross-linked polyamide containing at least one bifunctional additive that is hydrophilic and reactive. Additionally, in accordance with other embodiments of this invention, methods of forming water permeable membranes comprised of a cross-linked polyamide containing at least one bifunctional additive that is hydrophilic and reactive are provided. Specifically, the water permeable membranes may comprise a membrane formed from a cross-linked aromatic or aromatic/aliphatic polyamide interfacially polymerized on a porous support. The presence of the at least one hydrophilic and reactive additive improves the flux and salt retention properties of the membrane in comparison to a membrane formed without the at least one hydrophilic and reactive additive.