Ionic Liquid Ammonia Generator for Sensor Calibration
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Solution Overview
Problem
Existing electrochemical ammonia generators face issues with high vapor pressure of aqueous solutions leading to solvent evaporation and precipitation, requiring high maintenance and activation energies, and lacking long-term stability and intrinsic safety for use in gas sensor calibration and function testing.
Innovation Solution
An electrochemical gas generator using an ionic liquid-based nitrate salt electrolyte, such as ethylammonium nitrate, with a melting point below 25°C, which acts as both solvent and electrolyte salt in the generation reaction, providing drying resistance and long-term stability, and can be easily switched on and off with low technical effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous ammonia solutions or nitrate-containing aqueous salt solutions are used as electrolyte, then electrochemical ammonia generation is enabled, but the vapor pressure is high leading to solvent evaporation and precipitation
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrolyte by replacing aqueous solutions with ionic liquids. This fundamental parameter change eliminates the high vapor pressure issue while maintaining the electrochemical functionality for ammonia generation.
Solution Approach 2:
The patent employs composite ionic liquid systems combining multiple ionic liquids or ionic liquids with conventional solvents. This composite approach optimizes both the low vapor pressure characteristic and the electrochemical performance for stable, long-term ammonia generation.
2Productivity
If aqueous electrolyte solutions are used, then ammonia generation is achieved, but maintenance effort increases due to drying and precipitation issues
Solution Approach 1:
By changing the electrolyte from aqueous to ionic liquid, the patent eliminates the maintenance issues associated with evaporation and precipitation, while preserving the ammonia generation capability through electrochemical reduction of nitrate ions.
3Productivity
If conventional electrolyte systems are used, then ammonia can be generated, but activation energies are high and switching on/off is difficult
Solution Approach 1:
The patent changes the electrochemical parameters of the system by using ionic liquids with appropriate redox potentials. This enables ammonia generation at lower activation energies and allows for quick switching on and off by controlling the electrochemical reaction conditions.
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 generator achieves robust, low-maintenance ammonia production with high storage stability, intrinsic safety, and quick on/off functionality, suitable for long-term use in various climatic conditions for gas sensor calibration and testing.
Implementation Method 1
nitrate anions are reduced into ammonia: NO3−+8e++9H+→NH3+3H2O
Implementation Method 2
The great problem that the vapor pressure of aqueous nitrate-containing salt solutions is high occurs here as well, which in turn leads to the evaporation of the solvent
Data Source
AI summary
An electrochemical gas generator for ammonia with the use of ionic liquids containing nitrate ions as the electrolyte and to the use of the gas generator for generating gaseous ammonia, especially for testing the function of and/or calibrating gas sensors.