Cellulose Hydrate Membrane Pore Structure for Adsorption
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Solution Overview
Problem
Current adsorption membranes face limitations in hydraulic permeability and binding capacity, particularly in biopharmaceutical applications, where high mechanical and chemical stability, and efficient contaminant removal across a wide range of conditions are required, while existing methods are costly and environmentally unfriendly.
Innovation Solution
A cellulose hydrate membrane with functional groups on its inner and outer surfaces, formed by swelling and crosslinking of cellulose ester membranes during saponification, creating micropores and ultrapores that enhance binding capacity and permeability, allowing for improved contaminant removal and processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional adsorption membranes are used, then mechanical stability is maintained, but binding capacity and hydraulic permeability are limited
Solution Approach 1:
The patent utilizes cellulose hydrate with a controlled porous structure comprising micropores and ultrapores. The porous nature provides high surface area for ligand attachment (increasing binding capacity) while maintaining open channels for fluid flow (preserving hydraulic permeability). This resolves the contradiction by using the porous structure to simultaneously achieve both high binding capacity and high productivity.
Solution Approach 2:
The invention creates a composite structure by combining cellulose hydrate matrix with immobilized ligands on its surfaces. This composite approach allows the cellulose base to provide mechanical stability and porous structure, while the ligand layer provides high binding capacity, and the overall structure maintains hydraulic permeability through the controlled pore architecture.
2Productivity
If pore size is increased to improve flux, then hydraulic permeability increases, but binding capacity decreases
Solution Approach 1:
The patent segments the pore structure into two distinct types: micropores for convective flow and ultrapores for adsorption. This segmentation allows micropores to maintain hydraulic permeability while ultrapores provide binding sites, resolving the contradiction between flux and binding capacity by assigning different functions to different pore segments.
Solution Approach 2:
The invention applies local quality by creating regions with different pore characteristics - micropores optimized for flow and ultrapores optimized for binding. The ligands are specifically positioned on the surfaces accessible through these pores, creating local zones of high binding capacity within the overall porous structure that maintains high flux.
3Quantity of substance
If saponification is performed under swelling conditions, then binding capacity increases, but membrane structure changes
Solution Approach 1:
The patent controls the saponification process by adjusting parameters such as base concentration, temperature, and time to achieve the desired degree of swelling (1.05-1.50). By optimizing these parameters, the invention achieves sufficient structural change to create accessible ultrapores for binding while maintaining overall membrane integrity and mechanical stability.
Solution Approach 2:
The swelling action during saponification is used preliminarily to create the ultrapore structure and increase surface area before ligand attachment. This preliminary structural modification ensures that when ligands are subsequently introduced, they have access to maximized binding sites while the membrane retains sufficient structural stability for practical use.
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 cellulose hydrate membrane exhibits significantly higher binding capacities and hydraulic permeability compared to traditional methods, enabling effective removal of contaminants like viruses and proteins across varying operating conditions, thus addressing the limitations of existing adsorption membranes.
Implementation Method 1
brought into contact with at least one solution under conditions which lead to swelling of the cellulose ester matrix and at the same time, i.e. in situ, to hydrolysis (saponification) of the ester groups to hydroxyl groups
Implementation Method 2
hydrolysis (saponification) of the ester groups to hydroxyl groups
Implementation Method 3
the cellulose hydrate matrix obtained is crosslinked by reacting the hydroxyl groups with one or more at least bifunctional reagents
Implementation Method 4
functional groups (ligands) for adsorptive material separation on its inner and outer surfaces
Data Source
AI summary
The invention relates to a cellulose hydrate membrane having a porous double structure made of micropores having a diameter in the range from >100nm to 20 µm and ultrapores having a diameter of <100nm and not accessible to dextran blue having an average molecular weight Mw of 2,000,000, wherein the proportion of the volume of the ultrapores to the total pore volume accessible to water is greater than 15%. The invention further relates to a method for producing the membrane, the use thereof as an adsorption membrane, and a device for membrane chromatography.