NANO - TITANIUM DIOXIDE (TIO2) INTEGRATED CONCRETE: AN ASSESSMENT OF WEATHERING INTO NATURAL WATERS UNDER UV PHOTO ACTIVATION AND ACIDIC PRECIPITATION CONDITIONS

Nanomaterials have become increasingly applied in new commercial products and technologies without a complete understanding of their impact on the environment or human health. One such application is the integration of nano-sized titanium dioxide (nano-TiO₂) in concrete substrate for exploitation of its photo-catalytic properties as a self-cleaning construction material. There is a lack of knowledge regarding how nanomaterials utilized in this manner may erode from the concrete substrate during normal weathering and potentially enter surface water and groundwater environments.

Our research demonstrates through the use of accelerated ultraviolet (UV) weathering instrumentation and exposure to four different acidic water solutions, the concentration of nano-TiO₂ released from nano-TiO₂ integrated concrete, potentially impacting natural water sources. This durability testing model simulates an annual amount of UV and acid rain weathering by exposing nano-TiO₂ integrated concrete pucks to thirty UV photoactivation and acidic precipitation events. Effluent from each acidic rinse was subsequently analyzed by ICP-MS and ICP-OES for total titanium, calcium, and magnesium concentrations. Single particle ICP-MS, a relatively new method of measuring nano-sized particles in an aqueous solution, was performed to confirm and provide evidence of nano-TiO₂ release. This research provides evidence that normal weather conditions can impact the durability of nano-TiO₂ concrete applications, releasing nano-TiO₂ into surface and groundwater sources.