Zeolite-Modified Polyamide RO Membrane for Flux
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Solution Overview
Problem
Reverse osmosis membranes face challenges in achieving high permeate flux and maintaining a sufficient salt rejection rate, particularly when desalinating brackish or seawater, due to the high osmotic pressure requirements and complex structures that restrict their application.
Innovation Solution
A reverse osmosis membrane is manufactured with a porous support and a polyamide active layer that includes surface-treated zeolite with a silane compound having a glycidyl group, which improves the membrane's permeate flux while maintaining a high salt rejection rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphinyl alkyl chloride is added during interfacial polymerization to form a polyamide active layer, then permeate flux is increased, but salt rejection rate becomes unstable and deviates from required levels
Solution Approach 1:
The patent removes phosphinyl alkyl chloride from the interfacial polymerization process and replaces it with zeolite particles. This extraction of the problematic chemical additive resolves the contradiction by eliminating the source of salt rejection instability while maintaining the permeate flux enhancement through zeolite's physical structure and surface properties.
Solution Approach 2:
The patent changes the fundamental parameter of the active layer composition from chemical modification (phosphinyl alkyl chloride) to physical incorporation of zeolite particles. This parameter change transforms the mechanism of flux enhancement from chemical structure modification to physical pore formation and surface effects, thereby stabilizing salt rejection while maintaining high flux.
2Productivity
If pressure is increased to overcome high osmotic pressure of brackish or seawater, then water permeation is improved, but energy consumption increases significantly
Solution Approach 1:
The patent incorporates zeolite particles with well-defined porous structures into the polyamide active layer. These zeolite pores provide additional water transport pathways with lower resistance, enabling enhanced water permeation at reduced operating pressures, thus resolving the contradiction between permeation efficiency and energy consumption.
Solution Approach 2:
The patent creates a composite polyamide-zeolite active layer that combines the selective separation properties of polyamide with the high permeability and structured porosity of zeolite. This composite structure achieves superior water flux at lower pressures compared to conventional polyamide layers, addressing the energy consumption issue.
3Productivity
If zeolite is incorporated into the polyamide active layer to enhance permeate flux, then water passage is improved, but uniform distribution of zeolite particles becomes challenging
Solution Approach 1:
The patent performs preliminary surface treatment of zeolite particles with silane compounds before incorporation into the polyamide layer. This pre-treatment modifies the zeolite surface properties to improve compatibility with the polyamide matrix and prevent aggregation, ensuring uniform distribution during the subsequent interfacial polymerization process.
Solution Approach 2:
The patent introduces silane compounds as intermediary substances that bridge the zeolite particles and the polyamide matrix. The silane treatment creates a compatible interface between the inorganic zeolite and organic polyamide, facilitating uniform dispersion and stable integration of zeolite particles within the active layer structure.
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 membrane achieves enhanced permeate flux and maintains a high salt rejection rate, even at lower pressures, effectively addressing the limitations of existing technologies by uniformly distributing zeolite particles within the polyamide active layer.
Implementation Method 1
a film formed through interfacial polymerization occurring on a surface of a support layer by bringing an organic solvent containing an amine reactive compound such as a polyfunctional acyl halide or the like and phosphinyl alkyl chloride dissolved therein into contact with the support layer, after coating at least one aqueous polyfunctional amine solution on the support layer
Implementation Method 2
the reverse osmosis membrane, a type of semipermeable membrane, may remove salts from brackish water, sea water and the like, using a principle of causing a solution and a solute to be separated in predetermined directions when an aqueous solution having salts dissolved therein is pressurized in one direction
Implementation Method 3
At this time, the level of applied pressure needs to be greater than that of osmotic pressure. Accordingly, osmotic pressure is higher in accordance with an increase in salinity of the aqueous solution
Data Source
Figure 1~2
AI summary
The present invention relates to a reverse osmosis membrane including: a porous support; and a polyamide active layer formed on the porous support and including zeolite, surface-treated with a compound having at least one functional group selected from a group consisting of an amino group and a glycidyl group, and a method of manufacturing the same.