Air Pollution Control: Design and Develop Porous Adsorbents for Nitrous Oxide Removal

Mitigation of greenhouse gas emissions has become a hot topic in environmental chemistry and has garnered significant attention in both scientific research and industrial applications. That of particular concern is the potent greenhouse gas nitrous oxide, which has a global warming potential over 300 times higher than carbon dioxide. As such, efforts to mitigate anthropogenic nitrous oxide emissions are of the utmost importance in addressing climate change. There are a few known demonstrations of such greenhouse gas or pollutant mitigation in general environmental courses; therefore, we present a well-defined project about greenhouse gas removal. The main learning objective of this project is to help students solve a specific nitrous oxide mitigation problem using an adsorption-based separation technology. Theoretical knowledge about anthropogenic greenhouse gas emissions and porous materials for adsorption was introduced by the instructor. Then, a specific type of adsorbent, namely, transition-metal-exchanged chabazite, was used for demonstration. Students conducted experiments that involved the synthesis of the adsorbent, characterization of its properties, and measurements of its adsorption and separation performance. Based on the experimental results, students can learn basic knowledge about adsorption-related data analysis and discussion, such as isotherm model fitting and calculation of isosteric heat of adsorption. After reviewing the criteria for adsorbent design, students drew conclusions about whether this demonstrated zeolite material is an appropriate adsorbent for efficient nitrous oxide removal.