Surfactant Mesostructure Membranes for High-Flux Salt Rejection
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Solution Overview
Problem
Existing separation membranes suffer from low permeability and selectivity, particularly in applications like reverse osmosis and forward osmosis, due to high tortuosity and porosity, leading to inefficiencies in solvent flux and solute rejection.
Innovation Solution
A membrane comprising a stabilized surfactant mesostructure bonded to a porous support, with controlled pore size and tortuosity, utilizing surfactant alignment and hydrogen bonding to enhance permeability and selectivity, and optionally incorporating additional porous structures for mechanical stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional separation membranes are used, then structural stability is maintained, but permeability and selectivity are low due to high tortuosity and porosity
Solution Approach 1:
The patent uses surfactant mesostructures with controlled pore sizes (0.3-4 nm) to create separation membranes with optimized porosity. The surfactant self-assembled structures provide well-defined pore geometries that reduce tortuosity while maintaining structural stability, directly addressing the contradiction between permeability and structural complexity
Solution Approach 2:
The invention creates composite membranes by bonding stabilized surfactant mesostructures to porous support materials. This composite approach combines the ordered, low-tortuosity pore structure of surfactant assemblies with the mechanical strength of support materials, achieving both high permeability and structural stability
2Productivity
If membrane porosity is increased to improve solvent flux, then permeability increases, but solute rejection decreases
Solution Approach 1:
The surfactant mesostructure provides locally optimized pore characteristics with precise size control (0.3-4 nm) and uniform distribution. The ordered self-assembled structure ensures that local pore quality maintains both adequate solvent flux pathways and effective solute rejection barriers, resolving the trade-off between flux and selectivity
3Productivity
If surfactant alignment is enhanced to improve permeability, then structural stability may be compromised
Solution Approach 1:
The patent uses porous support materials as intermediary substrates to which surfactant mesostructures are bonded. The support material provides mechanical stability and structural framework, while the surfactant assembly maintains its aligned pore structure for high permeability. This intermediary approach allows both high productivity and structural stability to coexist
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 significantly higher permeability and solute rejection, with permeabilities up to 60 LM−2H−1 and NaCl rejection greater than 96%, outperforming conventional membranes by enhancing solvent flux and selectivity through controlled pore formation and surfactant alignment.
Implementation Method 1
biomimetic multiscale self assembly
Implementation Method 2
surfactant alignment and hydrogen bonding
Implementation Method 3
hydrogen bonding to enhance permeability and selectivity
Implementation Method 4
ultrafiltration membranes have pores of a specific size which prevents the crossover of molecules and particles of a specific size
Implementation Method 5
Flux=P*(ΔP−Δπ) where AP is the pressure across the membrane
Implementation Method 6
forward osmosis membranes
Data Source
AI summary
Stabilized surfactant-based membranes and methods of manufacture thereof. Membranes comprising a stabilized surfactant mesostructure on a porous support may be used for various separations, including reverse osmosis and forward osmosis. The membranes are stabilized after evaporation of solvents; in some embodiments no removal of the surfactant is required. The surfactant solution may or may not comprise a hydrophilic compound such as an acid or base. The surface of the porous support is preferably modified prior to formation of the stabilized surfactant mesostructure. The membrane is sufficiently stable to be utilized in commercial separations devices such as spiral wound modules. Also a stabilized surfactant mesostructure coating for a porous material and filters made therefrom. The coating can simultaneously improve both the permeability and the filtration characteristics of the porous material.