One-Step Zeolite Synthesis Without Organic Agents
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Solution Overview
Problem
The synthesis of zeolites without organic structure-directing agents (OSDAs) faces challenges such as limited Si/Al ratio range, polymorphism, and the need for post-synthesis calcination, which increases costs and environmental concerns, while also restricting the commercial viability and thermal stability of zeolites.
Innovation Solution
A one-step method for synthesizing high-silica zeolites, such as Zeolite HOU-2 (LTA type) and Zeolite Y (FAU type), using a silica to aluminum ratio of 2:1 or higher without OSDAs, rare earth element occlusion, and multivalent ions as extra-framework cations, allowing for crystallization at various temperatures to achieve high thermal stability and commercial ion exchange and catalysis applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If organic structure-directing agents (OSDAs) are used in zeolite synthesis, then the range of zeolite Si/Al ratio and framework types is improved, but the cost increases and post-synthesis calcination is required to remove organic molecules
Solution Approach 1:
The invention extracts and eliminates the organic structure-directing agent component from the synthesis system, replacing it with an all-inorganic gel composition. This removal eliminates the need for post-synthesis calcination to remove organics and reduces overall synthesis cost while maintaining the ability to produce diverse zeolite frameworks through inorganic gel chemistry control.
Solution Approach 2:
The invention changes the chemical composition parameters of the synthesis gel, specifically using an all-inorganic composition with controlled Si/Al ratios and specific molar proportions of alkali metals, alkali earth metals, and other inorganic components. This parameter adjustment allows the system to direct zeolite framework formation without organic agents, achieving both cost reduction and structural diversity.
2Object-generated harmful factors
If post-synthesis calcination is performed to remove organic molecules, then organic residues are eliminated, but energy consumption increases and environmental impact worsens
Solution Approach 1:
The invention extracts and removes the organic structure-directing agent from the synthesis system entirely, replacing it with inorganic gel components. This elimination prevents organic residue formation in the first place, making post-synthesis calcination unnecessary and thereby eliminating the associated energy consumption and environmental impact.
Solution Approach 2:
The invention converts the potential harm of organic residues into a benefit by using inorganic gel components that do not require removal. The inorganic components serve their structure-directing function and can be incorporated into or removed from the final product without the environmental and energy penalties associated with organic calcination.
3Ease of manufacture
If OSDA-free synthesis is used, then cost is reduced and environmental impact is minimized, but the range of zeolite Si/Al ratio is limited and polymorphism occurs
Solution Approach 1:
The invention systematically varies the molar ratios of inorganic gel components, particularly Si/Al ratios and the proportions of alkali metals, alkali earth metals, and other inorganic additives. These parameter changes enable the control of zeolite framework formation across a wide Si/Al ratio range while maintaining phase purity through optimized inorganic gel chemistry.
Solution Approach 2:
The invention introduces inorganic gel components as intermediary structure-directing agents that mediate between the synthesis conditions and the final zeolite structure. These inorganic gel components fulfill the structure-directing role traditionally performed by organics, enabling diverse zeolite formation without the drawbacks of OSDA usage.
4Device complexity
If conventional OSDA-free methods are used, then simplicity is maintained, but thermal stability of zeolites is reduced
Solution Approach 1:
The invention optimizes the composition parameters of the inorganic gel, specifically adjusting Si/Al ratios to higher values and controlling the proportions of stabilizing inorganic components. These parameter changes directly enhance the thermal stability of the resulting zeolite framework while maintaining the simplicity of the OSDA-free synthesis approach.
Solution Approach 2:
The invention creates a composite inorganic gel system combining multiple inorganic components (silica, alumina, alkali metals, alkali earth metals, and other inorganic additives) that work synergistically. This composite approach enhances the thermal stability of the resulting zeolite while keeping the synthesis method simple and OSDA-free.
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 method enables the production of zeolites with improved thermal stability and broader applicability, reducing costs by eliminating the need for OSDAs and post-synthesis dealumination, while maintaining phase purity and increasing the silicon-to-aluminum ratio beyond conventional limits, thus enhancing their commercial potential.
Implementation Method 1
the method comprises crystallization of the initial gel mixture
Implementation Method 2
the step of crystallization comprises heating the initial gel mixture from about 25° C. to about 100° C.
Data Source
AI summary
In an embodiment, the present disclosure pertains to a composition comprising a zeolite with high silica content. In some embodiments, the silica to aluminum ratio (SAR) for the zeolite is 2:1. In some embodiments, the zeolite comprises Zeolite HOU-2 (LTA-type). In some embodiments, the silica to aluminum ratio (SAR) for the zeolite is >3. In some embodiments, the zeolite comprises Zeolite HOU-3 (FAU type). In some embodiments, the zeolite is synthesized using a one-step method. In some embodiments, the zeolite is synthesized without the use of an organic structure-directing agent (OSDA). In some embodiments, the zeolite is synthesized without the use of post-synthesis dealumination. In some embodiments, the zeolite is synthesized without the use crystal seeds. In some embodiments, the zeolite is used in commercial ion exchange. In some embodiments, the zeolite is used for catalysis reaction. In some embodiments, the zeolite is highly thermostable.