Recent research published in the KSCE Journal of Civil and Environmental Engineering Research investigated the removal of toxic gases by using photocatalytic porous concrete.
1. Photocatalytic concrete
Photocatalytic concrete is an innovative material that has the potential to help mitigate air pollution in urban areas — a badly needed remedy to tackle air pollution. Recently, engineers at the Korea Institute of Civil Engineering and Building Technology (KICT) have demonstrated that this material can reduce pollution in tunnels.
This specific type of concrete contains a photocatalyst — typically titanium dioxide — which can initiate chemical reactions when exposed to ultraviolet light. Following the procedure, the team engineered concrete coated with titanium dioxide which produces molecules called reactive oxygen species (ROS) in the presence of sunlight.
2. Experiment
The team from KICT’s Green Construction by Photocatalyst Research Group (GCP), pioneers in developing cost-efficient photocatalysis technologies from wastewater sludge, experimented with an application of photocatalytic concrete in the Banpo Underground Road Tunnel in Seoul, South Korea.
The underground tunnel proved to be the ideal site for the experiment due to poor circulation and frequent traffic. Additional artificial lights were installed to accelerate light-activated reactions in areas unreachable by natural light. The result was a drop of the levels of nitrogen by 18% over 24 hours.
“Construction technology using photocatalysts can have an immediate effect on reducing fine particulate matter in the nation’s living environment. We plan to build a system of cooperation with local governments and public corporations to expand trial demonstrations to other sites to achieve commercialization and distribution with practical effects,” said Dr. Jong-Won Kwark, head researcher on the project.
3. Process
By incorporating photocatalytic concrete into roads and other paved surfaces, it’s possible to potentially reduce air pollution in urban areas, according to scientists. When sunlight or ultraviolet light interacts with the photocatalytic concrete, the titanium dioxide in the material triggers a photocatalytic reaction.
As vehicles pass over the concrete, the movement generates friction, which leads to the release of nitrogen oxides. However, when these pollutants come into contact with the photocatalytic concrete and are exposed to UV light, the photocatalytic reaction occurs, transforming them into less harmful compounds.
