Study of competitive adsorption of the N2O-CO2-CH4-N2 quaternary mixture on CuBTC

Exploring the Micropore Functional Mechanism of N2O Adsorption by the Eucalyptus Bark-based Porous Carbon

Nitrous oxide (N2O), recognized as a significant greenhouse gas, has received insufficient research attention in the past. In view of their low energy consumption and cost-effectiveness, the application of porous materials in adsorption is increasingly regarded as a potent strategy to reduce N2O pollution. In this study, a series of microporous porous carbons with a preeminent specific surface area (244.54-2018.08 m2 g-1), which are derived from the fast-growing eucalyptus bark, were synthesized by KOH activation at high temperatures. The obtained materials demonstrated a relatively fine N2O capture capability (0.19-0.68 mmol g-1) at normal temperature and pressure. More importantly, the optimal pore size affecting N2O adsorption (0.8 and 1.0 nm) has been detected, which is a meaningful view that has never been put forward in previous studies. The rationality of the N2O adsorption mechanism was also validated by combining the experimental analysis and Grand Canonical Monte Carlo (GCMC) simulation. The calculated results showed that 0.8 and 1.0 nm of the porous carbon were the preferred pore sizes for N2O adsorption, and the interaction force between N2O and the pore wall decreased with the increase of distance. This study provides a significant theoretical basis for the preparation of biomass porous carbon with excellent N2O adsorption performance and practical adsorption application.

Materials Design for N2O Capture: Separation in Gas Mixtures

The adsorption of greenhouse gases (GHG) as a method to reduce their emissions into the atmosphere is an alternative that is easier to implement industrially and cheaper than other existing technologies, such as chemical capture, cryogenic separation, or membrane separation. The vast majority of works found in the literature have focused their efforts on capturing CO2 as it is the largest GHG. However, although N2O emissions are not as large as CO2, the impact that N2O has on the stratosphere and climate is much larger in proportion, despite which there is not much research on N2O capture. Since both gases are usually emitted into the atmosphere together (along with other gases), it is necessary to design selective adsorbents capable of capturing and separating these gases from each other and from other gases, to mitigate the effects of climate change. This review aims to compile the existing information to date on porous adsorbents, the characteristics of the N2O adsorption processes and, above all, aims to focus the reader’s gaze on the importance of designing selective adsorbents for greenhouse gas mixtures.

MW-Assisted Regeneration of 13X Zeolites after N2O Adsorption from Concentrated Streams: A Process Intensification

N2O has a global warming potential about 300 times higher than CO2, and even if its contribution to the greenhouse effect is underrated, its abatement in industrial production’s tail gas has become imperative. In this work, we investigate the feasibility of the microwave (MW)-assisted regeneration of a 13X zeolite bed for N2O capture from tail gases. Several consecutive adsorption–desorption cycles were performed to verify the microwave heating effect on the zeolite’s adsorption properties. The results of the experimental tests, performed at N2O concentrations of 10, 20 and 40% vol, highlighted that (i) the steps are perfectly repeatable in terms of both adsorbed and desorbed amount of N2O, meaning that the MWs did not damage the zeolite’s structure, (ii) the presence of both H2O and O2 in the feed stream irreversibly reduces the adsorbent capacity due to nitrites and nitrates formation, and (iii) the presence of H2O alone with N2O still reduces the adsorbent capacity of the zeolites, which can be recovered through MW-assisted regeneration at 350 °C. Moreover, the MW-assisted TSA assured an energy and purge gas saving up to 63% and 82.5%, respectively, compared to a traditional regeneration process, resulting in effective process intensification.

Postsynthetic Modification of Metal-Organic Frameworks by Vapor-Phase Grafting

A vapor-phase grafting strategy is developed for the postsynthetic modification of metal-organic frameworks (MOFs). On the basis of the Schotten-Baumann reaction between acyl chloride (-COCl) and amino (-NH₂) groups and hydrolysis of -COCl, the carboxylated MOFs could be prepared through simple exposure in vaporized acyl chloride molecules and immersion in water. The modified MOFs have well-maintained crystalline structures and porosities and show substantially improved fluoride removal performance.