Could concrete help solve the problem of air pollution?
Researchers have discovered that sulfur dioxide, a major contributor to air pollution, is removed from the air by concrete surfaces. Their findings could be a significant step toward the practice of using waste concrete to minimise air pollution.
According to the World Health Organisation, as many as seven million premature deaths of people worldwide may be linked to poor air quality and pollution. Sulfur dioxide emissions are among the most common pollutants into the air globally, with power plants emitting the most sulfur dioxide. Cement kilns also produce approximately 20 percent of all sulfur dioxide industrial emissions.
Buildings serve as sponge
“Even though producing concrete causes air pollution, concrete buildings in urban areas can serve as a kind of sponge adsorbing sulfur dioxide to a high level,” explained Dr. Alex Orlov, Associate Professor of Materials Science and Chemical Engineering in the College of Engineering and Applied Sciences, at Stony Brook University. “Our findings open up the possibility that waste concrete coming from building demolitions can be used to adsorb these pollutants.”
Most widely used material
He added that concrete remains the most widely used material in the world and is inexpensive. Because of this, Dr. Orlov emphasised that “the strategy of using pollution causing material and turning it into an environmental solution could lead to new thinking in urban design and waste management.” Dr. Orlov cautioned that the capacity for concrete to adsorb pollutants diminishes over time as the material ages. Crushing concrete, however, can expose new surfaces and restore its pollution removing properties.
DRIFTS and XANES study
The researchers used various cement and cement-based building materials to conduct their experiments, details of which are in the paper, published in the the Journal of Chemical Engineering. They employed Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and X-ray absorption Near Edge Spectroscopy (XANES) to identify the levels of sulfur dioxide adsorption on the materials.
