Fe(II)-Substituted Beta Zeolite for NOx Adsorption
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Solution Overview
Problem
Existing methods for removing nitrogen monoxide and hydrocarbon gases from exhaust gases, particularly in the presence of high oxygen concentrations or low temperatures, are inefficient.
Innovation Solution
An Fe(II)-substituted beta type zeolite with specific physical properties, such as a SiO2/Al2O3 ratio of 10 to 18, BET specific surface area of 400 to 700 m2/g, and micropore volume of 0.15 to 0.25 cm3/g, is used for effective adsorption and removal of these gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional denitration catalysts (Fe3+-exchanged beta type zeolite) are used, then the catalyst structure is stable, but nitrogen monoxide adsorption efficiency is poor when oxygen concentration is high or temperature is low
Solution Approach 1:
The patent changes the oxidation state parameter of iron from Fe3+ (conventional) to Fe2+ (invention), and optimizes the SiO2/Al2O3 ratio parameter to 10-18. These parameter changes enable the catalyst to maintain structural stability while significantly improving nitrogen monoxide adsorption efficiency under high oxygen concentration and low temperature conditions.
Solution Approach 2:
The patent creates a composite material system combining Fe2+ ions exchanged into the beta type zeolite framework with specific SiO2/Al2O3 ratio (10-18). This composite structure achieves both structural stability and enhanced adsorption performance that neither component alone could provide.
2Quantity of substance
If beta type zeolite with low SiO2/Al2O3 ratio is used, then nitrogen monoxide adsorption capacity increases, but micropore volume and surface area may be reduced
Solution Approach 1:
The patent optimizes the SiO2/Al2O3 ratio parameter to a specific range (10-18) and controls Fe2+ exchange amount, achieving a balance where nitrogen monoxide adsorption capacity is maximized while micropore volume (0.15-0.25 cm3/g) and surface area are maintained at adequate levels.
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 Fe(II)-substituted beta type zeolite effectively adsorbs and removes nitrogen monoxide and hydrocarbon gases, even at high oxygen concentrations and low temperatures, improving adsorption efficiency and enabling effective gas cleaning in exhaust gases from internal combustion engines.
Implementation Method 1
a beta type zeolite which has been ion-exchanged with Fe(II) ions
Implementation Method 2
causing the nitrogen monoxide to be adsorbed onto an Fe(II)-substituted beta type zeolite
Data Source
AI summary
To provide an Fe(II)-substituted beta type zeolite which has been ion-exchanged with Fe(II) ions and can effectively adsorb and remove nitrogen monoxide or hydrocarbon contained in gas to be cleaned, even if oxygen is present in the gas at a high concentration or the temperature of the gas is low. In the Fe(II)-substituted beta type zeolite, a ratio of SiO2/Al2O3 is preferably 10 to 18, a BET specific surface area is preferably 400 m2/g to 700 m2/g, a micropore specific surface area is preferably 290 m2/g to 500 m2/g, and a micropore volume is preferably 0.15 cm3/g to 0.25 cm3/g. The amount of Fe(II) supported is preferably 0.01% by mass to 6.5% by mass based on the Fe(II)-substituted beta type zeolite.