Nitrogen Dioxide (NO2), the most prevalent oxide of nitrogen and important pollutant, is created and discharged upon the combustion of fossil fuels in various industrial mechanisms. This greenhouse gas has many damaging and toxic effects, both on the environment and human health. Therefore, the levels of the NO2 present in urban areas are frequently surveyed to indicate the quality of the air.
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One potential mechanism to remove NO2 from the atmosphere is through retention within various sorbents. However, a suitable sorbent is yet to be identified as many materials have low and irreversible uptake capacities.
Application of Gravimetric Sorption Analyzer
A recent study, which was published in Nature, used Hiden Isochema’s XEMIS-001 gravimetric sorption analyzer to be able to measure the discriminatory, reversible saturation of a metal-organic framework (MFM-300 (Al)) with nitrogen dioxide. Further analysis by X-ray and neutron scattering techniques were also utilized to monitor the interplay between the molecules of the material and the nitrogen dioxide.
Many different gases including SO2, CO2, CH4, N2 and O2 were used and identified that this MFM-300(AI) material exhibited an extremely high and reversible saturation with nitrogen dioxide, sustained over the course of several cycles. Additional gases were not taken up by this material as much as NO2 was, which therefore showed the high selectivity of the material.
Next, the adsorption-desorption isotherms for this gas were monitored at varying temperatures, and the isosteric enthalpy and entropy was calculated. According to this paper, the “isothermal adsorption of NO2 in MOFs has not been reported previously”.
The materials specificity for nitrogen dioxide was then further established through innovative analysis of NO2 uptake in varying environmental conditions in the presence of several other gas species. The obtained results agreed with the Ideal Adsorption Solution Theory (IAST) calculations utilizing the gravimetric sorption isotherms.
Despite the highly reactive nature of nitrogen dioxide, our material proved extremely robust. It is the first example of a metal-organic framework that exhibits a highly selective and fully reversible capability for repeated separation of nitrogen dioxide from the air, even in presence of water.
Dr Sihai Yang, Lead author, The University of Manchester, UK
Other studies of different porous materials found that they were unstable and decomposed with nitrogen dioxide, or that the regeneration process was too difficult and costly.
Professor Martin Schröder, Lead author, The University of Manchester, UK
We are delighted to read this publication from our customers and learn more about the environmentally beneficial applications for this material and MOFs in general. It is especially pleasing to see XEMIS gravimetric sorption analyzers being used in such an important area and contributing to cutting-edge research.
Dr Mark Roper, Sales and Marketing Director, Hiden Isochema
This information has been sourced, reviewed and adapted from materials provided by Hiden Isochema.
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