Zeolite Composite Membrane for Acidic Dehydration
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Solution Overview
Problem
Existing ceramic separation membranes face challenges with low acid resistance and separation performance when used for dehydration of acidic aqueous solutions, leading to restricted application ranges and durability issues.
Innovation Solution
A ceramic separation membrane with a porous substrate and a laminate separation layer comprising a zeolite base layer and a siliceous, organic amorphous silica, or carbonaceous outermost layer, providing high acid resistance and fast water permeation, is developed. The outermost layer is made of materials like DDR type zeolite with low Al atom content, and the base layer is made of chabazite type zeolite, enhancing separation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polymer membrane is used for membrane separation, then processing properties are excellent, but heat resistance is low and resistance to chemicals is low
Solution Approach 1:
The invention uses a composite membrane structure combining a polymer porous substrate with an inorganic separation layer (zeolite or ceramic coating). This composite approach allows the polymer substrate to provide excellent processing properties and porosity, while the inorganic separation layer provides high heat resistance and chemical resistance, particularly against organic solvents and acids.
2Reliability
If a zeolite membrane is used to remove water from acidic aqueous solution, then acid resistance is enhanced, but water permeation speed is low and concentration of acetic acid in permeated liquid is high
Solution Approach 1:
The invention creates a layered structure where different regions of the membrane have different functions: the polymer substrate provides porosity and processing advantages, while the inorganic separation layer provides acid resistance. Within the inorganic layer, specific zeolite structures (like DDR type) are selected to optimize both permeation speed and separation performance, achieving local optimization of properties.
3Duration of action of stationary object
If existing ceramic separation membranes are used for dehydration, then durability is improved, but separation performance is insufficient and concentration of organic material in permeated liquid becomes high
Solution Approach 1:
The invention optimizes key parameters of the inorganic separation layer including zeolite crystal structure (selecting DDR type), Si/Al ratio (controlling acidity), layer thickness, and pore size distribution. These parameter changes enable the membrane to achieve both high durability through acid resistance and excellent separation performance with low organic material concentration in permeate.
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 acid resistance and excellent separation performance, allowing continuous dehydration with maintained efficiency over time, reducing the concentration of organic materials in the permeated liquid and improving durability.
Implementation Method 1
a mixture (an acidic aqueous solution) of an organic material (an acid component such as acetic acid) and water is passed through this zeolite membrane, thereby allowing water to selectively permeate the membrane
Implementation Method 2
water to selectively permeate the membrane, so that the water can be removed from the acidic aqueous solution
Implementation Method 3
there has been suggested a membrane separation method in which a separation membrane (a ceramic separation membrane) having an inorganic material as in a zeolite membrane
Data Source
AI summary
There is disclosed a ceramic separation membrane. This ceramic separation membrane includes a porous substrate, and a separation layer formed on the substrate. The separation layer is a laminate having an outermost layer positioned on the most surface side, and a base layer positioned in a lower layer than the outermost layer and made of zeolite. The outermost layer is a layer made of a siliceous material containing 90 mol % or more of silica, an organic material-containing amorphous silica material having a Si—Cn—Si (wherein n is 1 or 2) bond and a Si/C ratio of 0.5 to 2, or a carbonaceous material containing 90 mass % or more of carbon. The outermost layer is different from the base layer.