Cellulose Ester Separation Membrane With Plasma-Modified Voids
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Solution Overview
Problem
Conventional separation membranes face challenges in achieving high membrane strength and permeation performance simultaneously, with hollow fiber membranes either exhibiting low separation performance due to yarn breakage during melt spinning or having insufficient membrane strength.
Innovation Solution
A separation membrane with an internal structure featuring specified voids and tensile elasticity, comprising cellulose esters, polyamides, or polyesters, which includes voids with specific dimensions and ratios, and surface grooves to enhance both separation and permeation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hollow fiber membrane is produced by melt spinning with high draft, then productivity is improved, but yarn breakage occurs causing insufficient membrane strength
Solution Approach 1:
The invention changes the physical and chemical parameters of the spinning system by introducing a plasma treatment step that modifies the surface properties of the fibers. This allows the membrane to achieve sufficient strength at lower spinning drafts, resolving the contradiction between productivity and strength.
Solution Approach 2:
The invention creates a composite structure by treating the cellulose ester fibers with plasma, which introduces functional groups and cross-linking on the fiber surface. This composite approach enhances inter-fiber bonding and membrane strength without requiring high spinning drafts.
2Strength
If hollow fiber membrane is produced by solution spinning, then membrane strength is improved, but separation performance decreases
Solution Approach 1:
The invention changes the spinning method from solution spinning to melt spinning with plasma treatment, adjusting the processing parameters to achieve both high strength and high separation performance simultaneously, rather than accepting the trade-off presented by conventional solution spinning.
3Productivity
If membrane thickness is reduced to increase permeation performance, then water permeation is improved, but membrane strength decreases
Solution Approach 1:
The invention changes the surface properties of the membrane through plasma treatment, which enhances the mechanical strength of thin membranes by introducing cross-linking and functional groups. This allows the membrane to maintain high permeation performance with reduced thickness while compensating for the strength loss through surface modification.
Solution Approach 2:
The invention utilizes a porous structure created by the plasma treatment process, which introduces voids and channels in the membrane matrix. This porous structure increases water permeation while the plasma-induced cross-linking maintains membrane strength, resolving the contradiction between permeation and strength.
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 high water permeation and salt rejection while maintaining sufficient membrane strength, as the voids and grooves increase contact area and reduce membrane thickness, leading to improved performance and stability.
Implementation Method 1
cellulose-based resins have permeation performance due to their hydrophilicity
Implementation Method 2
have chlorine resistance performance of being strong against chlorine bactericides
Data Source
AI summary
A problem to be solved by the present invention is to provide a separation membrane having excellent separation performance, having high membrane strength and high permeation performance, and mainly including a cellulose-based resin. The present invention is concerned with a separation membrane including a cellulose ester, having, in the interior thereof, voids each having a specified structure, and having a tensile elasticity of 1,000 to 6,500 MPa.