Organotemplate-Free CHA Zeolite Synthesis via Seeding
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Solution Overview
Problem
Current methods for producing CHA-type zeolitic materials are cost-intensive and environmentally unfriendly due to the need for organotemplates, which require high-temperature calcination and result in waste products, limiting the range of materials that can be produced and their physical and chemical properties.
Innovation Solution
A synthetic organotemplate-free process for producing zeolitic materials with a CHA-type framework structure using a mixture of YO2, X2O3, and optionally Z2O5, where seed crystals with a CHA framework structure are used, eliminating the need for organotemplates and reducing the process to mild conditions, allowing for a wide range of SiO2:Al2O3 molar ratios and microcrystalline products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organotemplates are used in the synthesis of CHA-type zeolites, then the zeolite framework structure can be directed and formed, but the process becomes cost-intensive and requires high-temperature calcination to remove the organotemplates
Solution Approach 1:
The invention extracts and eliminates the organotemplate component from the synthesis process entirely. By using a template-free approach with inorganic structure-directing agents (such as quaternary ammonium salts) and controlled synthesis conditions, the patent removes the need for costly organic templates and their subsequent removal via calcination, thereby reducing manufacturing costs and simplifying the process while still achieving the desired CHA-type zeolite framework structure
Solution Approach 2:
The invention changes the synthesis parameters by using milder hydrothermal conditions and inorganic additives instead of organic organotemplates. This parameter change allows the formation of the zeolite framework without requiring high-temperature calcination steps, thus resolving the contradiction between reliable structure formation and ease of manufacture
2Object-generated harmful factors
If high-temperature calcination is used to remove organotemplates, then the organotemplates can be eliminated from the pore structure, but energy consumption increases and harmful waste products are generated
Solution Approach 1:
The invention extracts and eliminates the high-temperature calcination step from the process by adopting a template-free synthesis approach. The resulting zeolites have inherently clean pore structures without organotemplate residues, eliminating the need for energy-intensive calcination and preventing harmful waste generation while maintaining the desired pore functionality
Solution Approach 2:
The invention converts the potential harm of organotemplate residues into a benefit by designing a synthesis process that never introduces organic templates in the first place. This approach transforms the problem of template removal into an advantage of inherently clean pore structures, achieving both environmental benefits and energy savings
3Manufacturing precision
If organotemplates are used in the synthesis process, then the zeolite can be produced with controlled structure, but the process becomes highly cost-intensive and environmentally unfriendly
Solution Approach 1:
The invention extracts and eliminates the harmful organotemplate component from the synthesis process while retaining structure control through alternative means. By using inorganic structure-directing agents and controlled hydrothermal synthesis conditions, the patent achieves precise zeolite structure formation without the environmental and economic costs associated with organic templates
Solution Approach 2:
The invention replaces expensive, environmentally harmful organotemplates with inexpensive, biodegradable inorganic additives that can be easily removed or remain as harmless residues. This substitution maintains manufacturing precision while dramatically reducing environmental impact and production costs
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 process enables the production of a wide variety of zeolitic materials with unprecedented properties, reducing costs and environmental impact by avoiding organotemplate use and high-temperature calcination, and allowing for intermediate to high Si contents, suitable for catalytic and adsorption applications.
Implementation Method 1
providing a mixture comprising one or more sources for YO2, one or more sources for X2O3, and seed crystals having a CHA framework structure
Implementation Method 2
crystallizing the mixture obtained in step (1)
Data Source
AI summary
The present invention relates to an organotemplate-free synthetic process for the production of a zeolitic material having a CHA-type framework structure comprising YO2, X2O3, and optionally comprising Z2O5, wherein said process comprises the steps of:(1) providing a mixture comprising one or more sources for YO2, one or more sources for X2O3, and seed crystals having a CHA framework structure, wherein the CHA framework structure of the seed crystals comprises YO2, X2O3, and optionally comprises Z2O5; and(2) crystallizing the mixture obtained in step (1);wherein Y is a tetravalent element, X is a trivalent element, and Z is a pentavalent element,wherein optionally one or more sources for Z2O5 are further provided in step (1), andwherein if the CHA framework of the seed crystals does not contain Z2O5, the seed crystals then have a YO2:X2O3 molar ratio of 5 or greater than 5.