Rejuvenation techniques for mortar containing photocatalytic TiO2 material

• Photocatalytic mortar panels tested showed substantial NOx mitigating properties.
• Weathered panels presented significantly depleted photocatalytic properties.
• Rejuvenation techniques showed varying results recovering photocatalytic efficiency.
• Acid etching was the most effective rejuvenation technique for photocatalytic mortar.

Mortar panels with embedded titanium dioxide particles were prepared to measure their photocatalytic efficiency for reducing nitrogen oxides pollutants from the air. The panels were tested in the as-cast condition and showed substantial NOx mitigating properties. The panels were then weathered by exposing them to summer poor air quality conditions for 120 days in two different locations within the Salt Lake City metropolitan area. After weathering the samples, they presented depleted photocatalytic properties. Rejuvenation techniques including hand sanding, walnut shell media blasting, and etching with muriatic acid were investigated. The rejuvenation techniques showed varying levels of effectiveness in returning the panels to mitigate low air quality.