Material that captures toxic air pollutantsDate: 27 November 2019 Tags: Nanotechnology
A team of scientists has developed a metal-organic framework (MOF) material that provides a selective, fully reversible and repeatable capability to capture a toxic air pollutant, nitrogen dioxide, produced by combusting diesel and other fossil fuels.
Capturing greenhouse and toxic gases from the atmosphere has been a challenge because of their relatively low concentrations and because water in the air competes with and can often negatively affect the separation of targeted gas molecules from other gases.
The material then requires only water and air to convert the captured gas into nitric acid for industrial use.
The mechanism for the record-breaking gas uptake by the MOFcould lead to air pollution control and remediation technologies that cost-effectively remove the pollutant from the air and convert it into nitric acid for use in producing fertilizer, rocket propellant, nylon and other products.
The material, denoted as MFM-520, can capture atmospheric nitrogen dioxide at ambient pressures and temperatures, even at low concentrations and during flow in the presence of moisture, sulfur dioxide and carbon dioxide.
Despite the highly reactive nature of the pollutant, MFM-520 proved capable of being fully regenerated multiple times by degassing or by treatment with water from the air.
The scientists used a chemical analysis technique called neutron spectroscopy, and computational techniques to precisely characterise how the new material captured nitrogen dioxide molecules.
The ability of neutrons to penetrate solid metal to probe the interactions between the nitrogen dioxide molecules and MFM-520 is helping the researchers validate a computer model of MOF gas separation and conversion processes.
Such a model could help predict how to produce and tailor other materials to capture a variety of different gases.