Selective Sonication-Assisted Deposition of Si-CHA Zeolite Membranes
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Solution Overview
Problem
The synthesis of uniform all-silica CHA zeolite membranes is hindered by the difficulty in forming submicrometer-sized and monodispersed Si-CHA zeolite particles, which is challenging due to inhomogeneous environments in fluoride media, and achieving a uniform seed layer is crucial for continuous film or membrane formation via secondary growth.
Innovation Solution
A selective sonication-assisted deposition method is employed, allowing plate-like Si-CHA particles to be preferentially deposited on a substrate, with physical interactions enabling high surface coverage and uniform layer formation, using a modified synthesis protocol that includes specific molar compositions and calcination processes to produce plate-like Si-CHA particles with controlled dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional synthesis methods are used to produce Si-CHA zeolite particles, then particles can be formed, but the particles are not uniform in size and shape, making it difficult to form a uniform seed layer
Solution Approach 1:
The patent modifies synthesis parameters including using a water-to-silica molar ratio of 3:1 or lower, adding hydrofluoric acid at controlled rates (0.05-0.5 mL/min), and controlling reaction temperature (150-190°C) and time (12-240 hours) to produce uniform plate-like Si-CHA particles with dimensions of 1-10 μm in length and 0.1-1 μm in thickness
Solution Approach 2:
The patent performs preliminary crushing of the synthesized zeolite powder to a fine powder state before deposition, and pre-establishes the plate-like particle morphology through controlled synthesis conditions, ensuring that particles are ready for uniform layer formation without requiring additional size selection steps
2Manufacturing precision
If plate-like Si-CHA particles are deposited on substrate, then uniform seed layer can be formed, but selective deposition of thin particles among mixed particle sizes is challenging
Solution Approach 1:
The patent introduces a dimensional constraint by placing the substrate between two parallel glass plates with a specific gap distance (0.5-2.0 mm), creating a confined space that allows only thin plate-like particles to reach the substrate surface while blocking larger or thicker particles
Solution Approach 2:
The patent uses ultrasonic waves as an intermediary mechanism to facilitate particle deposition. The ultrasonic treatment (20-40 kHz for 10-60 minutes) provides energy to disperse particles and promote their transport through the gap to the substrate surface, enabling selective deposition of plate-like particles
3Productivity
If sonication is applied to deposit particles, then particle deposition is enhanced, but energy consumption increases and particle damage may occur
Solution Approach 1:
The patent applies ultrasonic treatment at moderate conditions (20-40 kHz for 10-60 minutes) rather than excessive sonication, providing just enough energy to enhance particle deposition without causing significant particle damage or unnecessary energy consumption. This partial action achieves sufficient deposition efficiency while minimizing side effects
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 achieves uniform and oriented Si-CHA deposits as seed layers, facilitating the formation of continuous CHA membranes with desired pore channels, enhancing separation performance and reproducibility in zeolite membrane production.
Implementation Method 1
a second stage of sonication for the reached plate-like inorganic particles to be deposited uniformly on the substrate or support
Data Source
AI summary
Provided is a selective sonication-assisted deposition method of inorganic particles and CHA zeolite membranes grown from seeded uniform layers on substrates using the method and plate-like Si-CHA zeolite particles used for seed layer formation and manufacturing method of the same, in which thin inorganic particles may be selectively deposited on a substrate or on a support, and even a physical interaction between the deposited particles and supports (or substrates) alone allows for obtaining high surface coverage to form a uniform layer, which is critical in reproducible production of membranes of inorganic materials, such as zeolite, by secondary growth.