Photocatalytic NOx removal efficiency and surface reflectance of carbonated mortars. (21st February 2022)

• Record Type: Journal Article
• Authors: King, Daniel; Baral, Aniruddha; Roesler, Jeffery R.
• Is Part Of: Construction & building materials. Volume 320(2022)
• Publication Date: 2022-02-21
• Subjects: Photocatalytic concrete -- Photocatalytic cement -- NOx removal -- Carbonation -- Surface reflectance -- Albedo -- White cement -- Fly ash -- Titanium dioxide -- Sustainability; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.126210
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: NOx removal of uncarbonated photocatalytic white cement > gray photocatalytic cement. Higher diffuse reflectance in the UV-A region benefits NOx removal efficiency. 15% fly ash replacement provides the highest NOx removal efficiency after carbonation. White cement with 15% FA replacement had best NOx removal among carbonated specimens. Abstract: Photocatalytic concrete containing titanium dioxide (TiO2 ) nanoparticles can convert airborne nitrogen oxides (NOx ) into nitrate byproducts when exposed to light in the UV-A spectrum, which can reduce the impact to the environment and humans. In this study, the photocatalytic degradation of NOx by mortars containing anatase TiO2 was analyzed through photoreactor testing. Mortar mixtures were prepared with white and gray cements and varying TiO2 and fly ash contents to quantify the effects of carbonation and surface reflectance on each mix design's NOx removal potential. Carbonation of the mortar specimens significantly reduced photocatalytic NOx removal efficiency, but this could be offset by the replacement of cement with fly ash. Specimens containing photocatalytic white cement were highly reflective in the UV-A spectrum and demonstrated a NOx removal rate significantly greater than less reflective samples cast with gray cement. After carbonation, mixes with 15% fly ash replacement of cement produced the highest NOx removal efficiency for specimens containing the same source of cement.