Evaluation of photocatalytic efficiency of TiO2 applied over cement plaster for mitigating urban air pollutant: TVOC

Abstract

Photocatalysis emerged as a prominent method for mitigating air pollution stemming from emissions of total volatile organic compounds (TVOCs) in both indoor and outdoor environments. Given the slow degradation rate of certain TVOCs, which pose health risks, including carcinogenicity, there is a pressing need for effective air purification strategies, particularly within built environments where individuals spend substantial amounts of time. This study delves into the efficacy of TiO₂ photocatalysis in reducing air pollutants when applied to building surfaces. Cement mortar samples, incorporating varied doses of TiO₂ ranging from 7.83E-03 g/cm² to 4.92E-02 g/cm², were prepared and examined within batch reactors, both under sunlight exposure and in the absence thereof, to gauge their degradation rates towards TVOCs. Furthermore, surface characterization techniques were employed to explicate the microstructural properties of TiO₂-coated plastered samples. The results obtained demonstrated the variation in the rate of degradation from 1.09E-04±0.1 % to 3.1E-4 ± 1.13 % min⁻¹cm⁻² for various initial concentrations of total volatile organic compounds (TVOCs) in the range of 600 ppm to 2900 ppm over a period of 100 min. The selected approach demonstrated the maximum degradation rate constant of 5.2E-04 min⁻¹cm⁻² corresponding to 15 % of TiO₂ dose by weight of cement. These findings underscore the promise of TiO₂ in purifying polluted air and advocate for its widespread implementation on building surfaces to enhance air quality.