Fly Ash Ceramic Membrane Pore Formation via Liquid Phase Inversion
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Solution Overview
Problem
Current pore-forming agents for fly ash-based ceramic flat membranes face challenges in achieving uniformity and stability due to density differences, leading to low porosity and limited water flux, resulting in uneven cavity formation and disconnected holes.
Innovation Solution
A phase inversion pore-forming agent composed of poly(oxyphenylene sulfone) and N-methylpyrrolidone is used, which forms a solution with fly ash, allowing for uniform mixing and phase inversion to create straight-through pores with gradient distribution, enhancing porosity and filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solid pore-forming agents (starch, graphite) are used and mixed as dry powders, then the mixing process is simple, but the density difference between fly ash and pore-forming agents causes poor uniformity and stability during mixing
Solution Approach 1:
The patent changes the physical state of the pore-forming agent from solid to liquid by dissolving poly(oxyphenylene sulfone) in NMP solvent, creating a liquid pore-forming agent that can be uniformly mixed with fly ash slurry. This parameter change (solid→liquid) eliminates the density difference issue that causes poor mixing uniformity, while the liquid form allows for stable and homogeneous distribution throughout the ceramic body.
Solution Approach 2:
The patent introduces NMP (N-methylpyrrolidone) as an intermediary solvent that dissolves poly(oxyphenylene sulfone) to form a liquid pore-forming agent. This intermediary enables uniform mixing by acting as a medium that bridges the fly ash particles and the pore-forming polymer, ensuring homogeneous distribution before the solvent evaporates during sintering.
2Ease of manufacture
If conventional pore-forming agents are used, then the preparation process is straightforward, but the agents agglomerate inside and form uneven cavities during sintering
Solution Approach 1:
The patent changes the pore-forming agent from solid particles that tend to agglomerate to a liquid solution form. The liquid state allows the poly(oxyphenylene sulfone) to disperse uniformly throughout the fly ash slurry without agglomeration. During sintering, the solvent evaporates and the polymer decomposes to leave behind uniformly distributed pores, achieving precise control over pore formation.
3Ease of manufacture
If conventional pore-forming agents are used, then the mixing and processing is easy, but the resulting membrane has limited water flux due to disconnected holes
Solution Approach 1:
The patent changes the pore-forming agent to a liquid solution that can penetrate and connect throughout the ceramic matrix uniformly. This liquid form ensures that the polymer distributes evenly and forms a continuous network structure upon decomposition, creating interconnected pores that enable high water flux through the membrane, unlike the disconnected holes formed by conventional solid agents.
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 phase inversion pore-forming agent improves the porosity and filtration efficiency of ceramic flat membranes by forming uniform, straight-through pores, addressing the limitations of existing agents and enhancing water flux.
Implementation Method 1
After the raw materials are formed, water can be added to dissolve and removed the NMP by replacement to form pores
Implementation Method 2
The poly(oxyphenylene sulfone) is dissolved in the NMP to form a solution, which is mixed with ceramic material
Implementation Method 3
during the sintering, with the removal of poly(oxyphenylene sulfone), straight-through holes can be formed inside the ceramic material
Data Source
AI summary
The present disclosure provides a phase inversion pore-forming agent and a pore-forming method for a fly ash-based ceramic flat membrane support. The phase inversion pore-forming agent includes poly(oxyphenylene sulfone) and N-methylpyrrolidone (NMP), and is used in a preparation process of the fly ash-based ceramic flat membrane support. Pores can be formed through phase inversion, forming straight-through pores with gradient distribution inside the ceramic flat membrane support, thus avoiding a low porosity, a poor water flux, and uneven pore formation of the existing fly ash-based ceramic flat membrane support.