Seed Crystal Synthesis of Beta Zeolite Without OSDA
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Solution Overview
Problem
Current methods for producing beta zeolite require the use of organic structure-directing agents (OSDA), which are expensive and result in environmental pollution, and lack flexibility in achieving a wide range of SiO2/Al2O3 ratios suitable for industrial applications.
Innovation Solution
A method involving the use of a seed crystal with a particle size of 10 µm or less, synthesized without OSDA, and mixed with a reaction mixture containing silica, alumina, and alkali sources, to achieve a wide range of SiO2/Al2O3 ratios and reduce environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tetraethylammonium ion is used as an organic structure-directing agent for synthesizing beta zeolite, then the beta zeolite can be obtained with controlled composition, but the production cost increases and environmental pollution occurs
Solution Approach 1:
The invention extracts and removes the organic structure-directing agent (tetraethylammonium ion) from the synthesis system by using a seed crystal method. The seed crystal provides the necessary structural template for beta zeolite formation without requiring additional organic additives, thereby eliminating the harmful factors associated with OSDA while maintaining composition control.
Solution Approach 2:
The seed crystal serves as a self-organizing template that directs the formation of beta zeolite with controlled composition without external organic structure-directing agents. The crystal structure of the seed crystal itself provides the necessary guidance for epitaxial growth, making the system self-sufficient and eliminating the need for harmful OSDA.
2Stability of the object's composition
If tetraethylammonium ion is incorporated into beta zeolite crystal, then the crystal structure is formed, but calcination is required which generates exhaust gases and requires detoxification treatment
Solution Approach 1:
The invention extracts the organic component (tetraethylammonium ion) from the crystal formation process by using a seed crystal method. The seed crystal provides the structural template without incorporating organic ions that would require calcination, thereby eliminating exhaust gas generation and detoxification requirements while maintaining crystal structure stability.
3Ease of manufacture
If a narrow composition range is used for the reaction mixture, then the synthesis process is simplified, but the SiO2/Al2O3 ratio of the zeolite is limited to a limited range
Solution Approach 1:
The invention changes the composition parameters of the reaction mixture to enable a wide range of SiO2/Al2O3 ratios. By adjusting the molar ratios of silica source, alumina source, and alkali source within specific ranges, the method achieves both process simplicity and versatility in producing beta zeolite with different compositions suitable for various industrial applications.
4Productivity
If conventional synthesis method is used, then beta zeolite can be produced, but the method has great environmental load and is expensive
Solution Approach 1:
The invention uses a seed crystal that directs the self-organization of silica and alumina sources to form beta zeolite without requiring organic structure-directing agents. This self-service mechanism eliminates the need for expensive and environmentally harmful OSDA, thereby reducing both production costs and environmental load while maintaining high productivity for industrial-scale production.
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
This approach allows for the production of beta zeolite with a wide SiO2/Al2O3 ratio range, reducing production costs and environmental load, and enables the synthesis of a 'green beta zeolite' without the need for OSDA, facilitating industrial-scale production.
Implementation Method 1
a method for producing a beta zeolite using no OSDA has been proposed in Non Patent Document 4. In this method, the beta zeolite synthesized using tetraethylammonium ions is calcined to remove organic components and the obtained product is used as a seed crystal. The seed crystal is added to a sodium aluminosilicate reaction mixture containing no organic substance, a hydrothermal treatment is performed, and thereby crystallization is performed.
Implementation Method 2
The seed crystal is added to a sodium aluminosilicate reaction mixture containing no organic substance, a hydrothermal treatment is performed, and thereby crystallization is performed.
Data Source
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AI summary
Provided is a method for producing a beta zeolite, which is a seed crystal addition method that is capable of reducing the environmental load as much as possible. A method for producing a beta zeolite according to the present invention comprises a step wherein a reaction mixture that contains a silica source, an alumina source, an alkali source and water and a seed crystal that is composed of a beta zeolite are mixed with each other and heated. A beta zeolite which comprises particles having a particle size of 10 µm or less in an amount of 90% or more on a volume basis in the particle size distribution as determined by a laser diffraction/scattering particle size distribution measuring method, and which is synthesized without using an organic structure-directing agent is used as the seed crystal.