Concrete surfaces can help tackle air pollution as it absorbs sulphur dioxide – a major pollutant, scientists including one of Indian origin have found. 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, researchers said. This could be a significant step toward the practice of using waste concrete to minimise air pollution, they said.
“Even though producing concrete causes air pollution, concrete buildings in urban areas can serve as a kind of sponge adsorbing sulphur dioxide to a high level,” said Alex Orlov, associate professor at Stony Brook University in the US.
“Our findings open up the possibility that waste concrete coming from building demolitions can be used to adsorb these pollutants,” Orlov said. According to the World Health Organization (WHO), as many as seven million premature deaths of people worldwide may be linked to poor air quality and pollution.
Sulphur dioxide emissions are among the most common pollutants into the air globally, with power plants emitting the most sulphur dioxide. Cement kilns also produce about 20 per cent of all sulphur dioxide industrial emissions. Concrete remains the most widely used material in the world and is inexpensive.
Researchers, Girish Ramakrishnan from Stony Brook University, used various cement and cement-based building materials to conduct their experiments.
They employed Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and X-ray absorption Near Edge Spectroscopy (XANES) to identify the levels of sulphur dioxide adsorption on the materials. Researchers 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. The study was published in the Journal of Chemical Engineering.