Ceramic Filter Membrane Adhesion via Sol-Gel Penetration
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Solution Overview
Problem
Existing ceramic filter technologies face challenges in forming uniform membranes with few defects, particularly on monolith substrates, and suffer from membrane peeling due to solvent flow during drying, leading to inadequate separation performance and high operational costs.
Innovation Solution
A ceramic filter is designed with a silica membrane having an average pore size smaller than the ultrafiltration membrane, which is formed on a porous substrate, achieving an average membrane thickness of 0.1 to 1.0 µm, allowing the ceramic porous membrane to penetrate into the ultrafiltration membrane and substrate, enhancing adhesion and preventing peeling, while maintaining high flux and separation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the filtration membrane formation method is used to form a porous membrane on the inner surface of a porous substrate, then the membrane can be formed on the inner surface by maintaining lower pressure on the outer surface side, but solvent present in pores of the substrate may flow out toward the membrane side upon drying after forming the membrane to cause peeling of the membrane
Solution Approach 1:
The patent applies preliminary action by forming the porous membrane before the substrate is completely dried. The membrane formation process is conducted while the substrate still contains solvent in its pores, allowing the membrane to penetrate and adhere to the substrate structure. The drying process is then completed after membrane formation, preventing solvent flow that would cause peeling.
Solution Approach 2:
The patent utilizes porous materials by forming a porous membrane on a porous substrate. The membrane itself has a porous structure with controlled pore size distribution, allowing it to maintain adhesion with the substrate while providing filtration functionality. The porous structure enables the membrane to integrate with the substrate's pore network.
2Ease of manufacture
If the hot coat method is used to form a porous membrane on the outer surface of a heated tube substrate, then a membrane can be formed by application of fabric containing silica sol with rubbing, but uniform membrane cannot be formed on the entire surface and membrane can be formed only on the outer surface of the tube
Solution Approach 1:
The patent applies inversion by reversing the conventional approach: instead of forming the membrane on the outer surface of the substrate (hot coat method), the membrane is formed on the inner surface. This inversion allows the membrane-forming solution to be introduced through the fluid passage and uniformly coat the inner surface, achieving consistent membrane thickness and properties throughout.
Solution Approach 2:
The patent utilizes pneumatics and hydraulics by introducing the membrane-forming solution through the fluid passage of the substrate. Pressure differential is applied to drive the solution through the substrate and facilitate uniform membrane formation on the inner surface, replacing mechanical rubbing methods.
3Adaptability or versatility
If the dipping method is used to form a membrane, then it can be applied to a monolith type substrate, but the number of membrane formation operations is large
Solution Approach 1:
The patent applies merging by combining multiple functions into a single operation. The membrane-forming solution contains both the binding agent and pore-forming components, allowing the membrane to be formed in one dipping operation rather than requiring separate steps for membrane formation and pore structure creation. This reduces the total number of operations while maintaining versatility across substrate types.
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 solution results in a ceramic filter with a thin, uniform, and defect-free membrane, offering high separation performance and cost-effectiveness, particularly suitable for dehydration processes like ethanol and acetic acid separation.
Implementation Method 1
a ceramic porous membrane (1) having an average pore size smaller than that of an ultrafiltration membrane is formed on the inner wall surface of the ultrafiltration membrane
Implementation Method 2
a sol-gel type method
Data Source
Figure 1~2
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AI summary
There is provided a ceramic filter provided with a ceramic porous membrane having few defects, small and uniform membrane thickness, and high resolution performance. The ceramic filter includes: a porous substrate11 which is a microfiltration membrane (MF membrane), a titania UF membrane 14 which is an ultrafiltration membrane (UF membrane) formed on the porous substrate 11 and has an average pore size of 2 to 20 nm and an average thickness of 0.1 to 1.0 µm, and a silica membrane 1 which is formed on the titania UF membrane 14 and a ceramic porous membrane a part of which has penetrated into pores of the titania UF membrane 14 or into pores of the UF membrane 14 and the porous substrate 11.