New material turns toxic air pollutant into industrial chemical

London: An international team of scientists has developed a new material that can capture a toxic pollutant produced by burning fossil fuels and convert it into useful industrial chemicals using only water and air.

The technology could lead to air pollution control and help remedy the negative impact nitrogen dioxide has on the environment.

The metal-organic framework (MOF) material provides a selective, fully reversible and repeatable capability to capture nitrogen dioxide (NO2), a toxic air pollutant produced particularly by diesel and bio-fuel use, said the study published in the journal Nature Chemistry.

The NO2 can then be easily converted into nitric acid, a multi-billion dollar industry with uses including, agricultural fertiliser for crops; rocket propellant and nylon.

MOFs are tiny three-dimensional structures which are porous and can trap gasses inside, acting like cages.

"This is the first MOF to both capture and converts a toxic, gaseous air pollutant into a useful industrial commodity," said Sihai Yang, a lead author and a senior lecturer at the University of Manchester in Britain.

"It is also interesting that the highest rate of nitrogen dioxide uptake by this MOF occurs at around 45 degrees Centigrade, which is about the temperature of automobile exhausts."

The material, named MFM-520, can capture nitrogen dioxide at ambient pressures and temperatures -- even at low concentrations and during flow -- in the presence of moisture, sulfur dioxide and carbon dioxide, said the study.

The highly efficient mechanism in this new MOF was characterised by researchers using neutron scattering and synchrotron X-ray diffraction at the US Department of Energy's Oak Ridge National Laboratory and Berkeley National Laboratory, respectively.

The team also used the National Service for Electron Paramagnetic Resonance Spectroscopy at Manchester to study the mechanism of adsorption of nitrogen dioxide in MFM-520.

"The global market for nitric acid in 2016 was $2.5 billion, so there is a lot of potential for manufacturers of this MOF technology to recoup their costs and profit from the resulting nitric acid production. Especially since the only additives required are water and air," Martin Schroder, Professor at the University of Manchester.