Cu-Chabazite Zeolite Catalyst via In-Slurry Ion Exchange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for preparing Cu-zeolite catalysts using liquid-phase ion exchange are complex, costly, and result in reduced NOx high-temperature activity, with challenges in varying copper loading and manufacturing efficiency.
Innovation Solution
The development of an in-slurry ion exchange (ISIE) process to selectively ion-exchange copper in zeolite pores, allowing for a specific Cu2+ (α)/Cu2+ (β) ratio determination through NO adsorption, enabling the creation of a novel Cu-zeolite structure with enhanced high-temperature activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid-phase ion exchange (LPIE) is used to prepare Cu-zeolite, then copper ion exchange can be achieved, but the process becomes complex and time-consuming with increased manufacturing costs
Solution Approach 1:
The patent replaces the conventional liquid-phase ion exchange process with a mechanical ball-milling method. Copper-containing powder is mixed with zeolite powder and subjected to ball-milling, which mechanically facilitates copper ion exchange without requiring complex liquid-phase processing steps, thereby simplifying the manufacturing process while maintaining effectiveness
Solution Approach 2:
The patent changes the fundamental processing parameters from liquid-phase chemistry to solid-state mechanical processing. By using ball-milling with specific milling times (1-24 hours) and copper powder ratios (0.1-10 wt%), the process achieves copper ion exchange through mechanical energy input rather than chemical solution processing, reducing complexity and time
2Quantity of substance
If conventional LPIE method is used to prepare Cu-zeolite catalyst, then copper loading can be adjusted, but NOx high-temperature activity is lowered
Solution Approach 1:
The patent applies preliminary mechanical activation through ball-milling before final catalyst formation. This pre-treatment creates optimal copper distribution and ion exchange conditions in advance, ensuring that when the catalyst is used at high temperatures, the copper is already in the correct positions and states to maintain high NOx activity regardless of loading amount
Solution Approach 2:
The patent changes the copper introduction method from wet chemical impregnation to mechanical mixing and milling with copper powder. This parameter change allows precise control of copper loading while maintaining metallic or highly dispersed copper states that preserve high-temperature activity, unlike conventional LPIE which may create less active copper species
3Adaptability or versatility
If Cu-zeolite is prepared through LPIE and then mixed with binder and additive, then catalyst composition can be formulated, but the process takes long time and increases manufacturing costs
Solution Approach 1:
The patent merges multiple sequential steps into a single integrated ball-milling process. Copper powder, zeolite, binder, and additives are all mixed and processed together in one ball-milling operation rather than separately preparing Cu-zeolite first and then combining with other components, significantly reducing manufacturing time while maintaining composition flexibility
Solution Approach 2:
The ball-milling process serves multiple functions simultaneously: it performs copper ion exchange, mixes catalyst components, distributes binder and additives, and prepares the final catalyst composition. This multi-functional approach eliminates the need for separate processing steps, reducing both time and cost while maintaining versatility in formulation
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 ISIE process simplifies copper ion exchange, allows precise control of copper loading, and significantly improves NOx purification activity at high temperatures compared to conventional methods, maintaining high NOx conversion rates and minimizing N2O formation.
Implementation Method 1
the zeolite catalyst composition is typically applied onto the inner walls of a honeycomb carrier. Briefly describing the overall process of preparing the catalyst composition, Cu-zeolite is purchased from a commercial source, mixed with deionized water, a binder and an additive, and dispersed to afford a Cu-zeolite catalyst composition
Implementation Method 2
Since NO (nitrogen monoxide) adsorbed to Cu2+ (α) and Cu2+ (β) shows DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) absorption bands at different positions, the Cu2+ (α)/Cu2+ (β) ratio may be calculated accurately
Data Source
AI summary
The present invention relates to zeolite containing Cu2+ (α) and Cu2+ (β) having different NO adsorption capacities loaded at a specific ratio, wherein the zeolite is chabazite (CHA)-type zeolite, particularly chabazite (CHA)-type zeolite loaded with divalent copper ions in which the NO adsorption area ratio of Cu2+ (α)/Cu2+ (β) after exposure to NO (nitrogen oxide) for 180 sec is 80% or more. In addition, the present invention relates to a method of preparing zeolite that is ion-exchanged in a slurry state and to a catalyst including the specified chabazite (CHA)-type zeolite.