Composite Semipermeable Membrane With Collapse-Resistant Porous Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing composite semipermeable membranes used in seawater desalination experience decreased water permeability and volume due to high temperature and pressure, leading to reduced performance over time.
Innovation Solution
A composite semipermeable membrane with a porous layer and separation functional layer, where the surface layer elastic modulus is between 0.6 GPa and 1.0 GPa, and a dense layer with porosity of 10% or less and thickness of 300 nm or less, combined with specific surface roughness ratios and pore area ratios, to maintain water production under high pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure and high temperature operation is performed to increase water production, then water permeability initially improves, but the support layer collapses and water permeability decreases over time
Solution Approach 1:
The patent applies preliminary densification treatment to the porous layer before actual operation. By pre-compressing the membrane at controlled conditions (5-10 MPa, 25-50°C for 1-48 hours), the porous structure is stabilized in advance, preventing collapse during subsequent high-pressure operation and maintaining reliable water permeability
Solution Approach 2:
The patent optimizes specific parameters including surface layer elastic modulus (0.6-1.0 GPa), dense layer thickness (≤300 nm), and porosity (≤10%) to achieve the right balance between initial productivity and long-term reliability. These parameter changes enable the membrane to withstand operational pressures without structural collapse
2Stability of the object's composition
If the porous layer is made more dense to prevent collapse under pressure, then structural stability improves, but initial water permeability decreases
Solution Approach 1:
The patent creates a dense layer with specific properties (thickness ≤300 nm, porosity ≤10%) at the surface of the porous layer, while maintaining higher porosity in the bulk. This local quality differentiation provides structural stability where needed (at the pressurized surface) while preserving water permeability pathways in the interior
Solution Approach 2:
By pre-densifying the porous layer before operation, the membrane achieves structural stability without sacrificing initial permeability. The controlled densification process (5-10 MPa, 25-50°C for 1-48 hours) optimizes the porous structure to be collapse-resistant while maintaining open pathways for water flow
3Strength
If the support layer skeleton strength is increased to resist densification, then pressure resistance improves, but manufacturing complexity increases
Solution Approach 1:
The patent achieves enhanced skeleton strength by controlling the surface layer elastic modulus within 0.6-1.0 GPa through material composition adjustments and processing parameters. This approach strengthens the support structure without requiring complex multi-layer designs or additional reinforcement components
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 maintains excellent water production and desalination performance even after high-temperature and high-pressure operations, preventing collapse of the porous structure and ensuring consistent water permeability.
Implementation Method 1
at least one of a surface layer elastic modulus (EA) and a surface layer elastic modulus (EB) is 0.6 GPa or more and 1.0 GPa or less
Implementation Method 2
A composite semipermeable membrane having a substrate, a support layer, and a separation functional layer is used for a reverse osmosis treatment for removing a solute from raw water
Implementation Method 3
a pressure equal to or greater than a difference between an osmotic pressure on a supply water side and an osmotic pressure on a permeate water side is applied to the supply water side
Data Source
AI summary
The present invention relates to a composite semipermeable membrane including a porous layer and a separation functional layer provided on the porous layer, in which at least one of a surface layer elastic modulus (EA) and a surface layer elastic modulus (EB) is 0.6 GPa or more and 1.0 GPa or less, provided that the surface layer elastic modulus (EA) is obtained by measuring a surface of the porous layer pressurized under a condition A (7 MPa, 35° C., 6 hours) with an atomic force microscope (AFM) and the surface layer elastic modulus (EB) is obtained by measuring the surface of the porous layer pressurized under a condition B (7 MPa, 45° C., 24 hours) with the atomic force microscope (AFM).