Phospholipid-Dispersed Polyamide Membranes for High-Flux Salt Rejection
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Solution Overview
Problem
Existing RO and NF membranes face challenges in balancing high permeability with acceptable solute rejection, particularly due to the complexity and cost of incorporating biological proteins like aquaporins, and the fabrication issues with nanocomposite membranes.
Innovation Solution
A method involving impregnating a porous membrane substrate with a mixture of polyamine and phospholipid, followed by an interfacial polymerization with a crosslinking monomer to form a polyamide layer containing dispersed phospholipids, which enhances membrane permeability and solute rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If biological proteins like aquaporins are incorporated into the membrane, then water permeability is improved, but production cost and process complexity increase
Solution Approach 1:
The patent extracts the water channel function from biological proteins and implements it through synthetic phospholipid molecules. The phospholipids are incorporated into the polyamide layer during interfacial polymerization, providing water-selective channels without requiring complex protein expression and purification processes. This extraction of the functional element enables simplified production while maintaining high water permeability.
Solution Approach 2:
The patent replaces expensive and complex biological proteins with inexpensive synthetic phospholipids. The phospholipids can be easily synthesized chemically and incorporated into the membrane during fabrication, eliminating the need for costly protein production, purification, and reconstitution steps. This substitution dramatically reduces manufacturing complexity and cost.
2Adaptability or versatility
If nanomaterials are incorporated into polymeric membranes, then membrane properties are modified, but fabrication difficulty and operational issues increase
Solution Approach 1:
The patent merges the phospholipid incorporation step with the polyamide layer formation step during interfacial polymerization. The phospholipids are present in the aqueous phase during the polymerization process, allowing them to be simultaneously incorporated into the forming polyamide layer. This merging of steps eliminates separate fabrication procedures and simplifies manufacturing.
Solution Approach 2:
The patent changes the chemical parameters of the membrane formation process by using phospholipids as additives in the aqueous phase during interfacial polymerization. This parameter change allows the phospholipids to be incorporated into the polyamide layer structure, modifying membrane properties such as hydrophilicity and water permeability without requiring separate nanomaterial incorporation steps.
3Productivity
If selective layers with nanoparticles are deposited on membrane substrate, then water permeability is improved, but solute rejection may be compromised
Solution Approach 1:
The patent applies local quality by incorporating phospholipids specifically into the polyamide layer structure during formation. The phospholipids are distributed within the polyamide matrix, creating localized water-selective channels while maintaining the overall structural integrity and solute rejection capability of the membrane. This localized modification enables enhanced water permeability without compromising solute rejection.
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 composite membrane achieves water permeability up to 6-8 times greater than conventional membranes without phospholipids, maintaining a salt rejection rate of at least 90%, comparable to aquaporin-containing membranes, while being easier and less costly to produce.
Implementation Method 1
contacting the impregnated surface with an organic phase containing a monomer comprising at least one crosslinking group to thereby deposit a polyamide layer on the impregnated surface, wherein the polyamide layer comprises the phospholipid dispersed therein, and wherein the polyamide layer is an interfacial polymerization product
Data Source
AI summary
The present invention relates to a method for producing a composite membrane, the method comprising impregnating a surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one phospholipid; and contacting the impregnated surface with an organic phase containing a monomer to thereby deposit a polyamide layer on the impregnated surface. The present invention also relates to a composite membrane comprising at least one porous membrane substrate having nano-sized or micro-sized pores; and at least a polyamide layer disposed on a surface of the porous membrane substrate, the polyamide layer comprising at least one phospholipid dispersed therein, and wherein the polyamide layer is an interfacial polymerization product.