Effect of weathering and traffic exposure on removal of nitrogen oxides by photocatalytic coatings on roadside concrete structures

Cros, Clement; Terpeluk, Alexandra L.; Burris, Lisa E.; Crain, Neil; Corsi, Richard L.; Juenger, Maria

doi:10.1617/s11527-014-0388-2

Cited by 11 publications

(9 citation statements)

References 29 publications

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“…For example, a recent study showed that a photocatalytic coating applied over concrete and plaster maintained about 80% of its initial activity after two years of continuous exposure to polluted urban air [16]. Similarly, a few large-scale field demonstrations of newly installed photocatalytic cementitious materials have been performed, showing disparate results ranging from excellent to poor de-NOx efficacy [17][18][19][20][21][22][23][24]. The de-NOx performance can change over time as materials are continuously exposed to the environment because photocatalytic efficacy is influenced by the buildup of recalcitrant residues on the surface (including microbial soiling) and by other physical and chemical changes associated with material aging.…”

Section: Introductionmentioning

confidence: 99%

De-pollution efficacy of photocatalytic roofing granules

Tang

Ughetta

Shannon

et al. 2019

Building and Environment

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Photocatalytic building surfaces can harness sunlight to reduce urban air pollution. The NOx abatement capacity of TiO2-coated granules used in roofing products was evaluated for commercial product development. A laboratory test chamber and ancillary setup were built following conditions prescribed by ISO Standard 22197-1. It was validated by exposing reference P25-coated aluminum plates to a 3 L min -1 air flow enriched in 1 ppm NO under UVA irradiation (360 nm, 11.5 W m -²). We characterized prototype granule-surfaced asphalt shingles and loose granules prepared with different TiO2 loadings and post-treatment formulations. Tests performed at surface temperatures of 25 and 60 °C showed that NOx abatement was more effective at the higher temperature. Preliminary tests explored the use of 1 ppm NO2 and of 1 ppm and 0.3 ppm NO/NO2 mixtures. Specimens were aged in a laboratory accelerated weathering apparatus, and by exposure to the outdoor environment over periods that included dry and rainy seasons. Laboratory aging led to higher NO removal and NO2 formation rates, and the same catalyst activation was observed after field exposure with frequent precipitation. However, exposure during the dry season reduced the performance. This inactivation was mitigated by cleaning the surface of field-exposed specimens. Doubling the TiO2 loading led to a 50-150 % increase in NO removal and NOx deposition rates. Application of different post-treatment coatings decreased NO removal rates (21-35%) and NOx deposition rates (26-74%) with respect to untreated granules. The mass balance of nitrogenated species was assessed by extracting granules after UV exposure in a 1 ppm NOenriched atmosphere.

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Section: Introductionmentioning

confidence: 99%

De-pollution efficacy of photocatalytic roofing granules

Tang

Ughetta

Shannon

et al. 2019

Building and Environment

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“…However, after four cycles, the degradation rates of NO x , CO, and CO 2 remained stable, demonstrating good reusability of the coating. This may be due to the confinement effect of the acrylic emulsion on doped TiO 2 , which does not change the dispersion state of the doped TiO 2 on the surface of the coating during the scouring process [59].…”

Section: Resultsmentioning

confidence: 99%

The Photocatalytic Degradation of Vehicle Exhausts by an Fe/N/Co–TiO2 Waterborne Coating under Visible Light

et al. 2019

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Based on the three-dimensional network structure of a polymer and the principle of photocatalysts, a visible-light-responsive and durable photocatalytic coating for the degradation of vehicle exhaust (VE) has been constructed using a waterborne acrylic acid emulsion as the coating substrate; Fe/N/Co–TiO2 nanoparticles (NPs) as photocatalytic components; and water, pigments, and fillers as additives. The visible-light-responsive Fe/N/Co–TiO2 NPs with an average size of 100 nm were prepared by sol-gel method firstly. The co-doping of three elements extended the absorption range of the modified TiO2 nanoparticles to the visible light region, and showed the highest light absorption intensity, which was confirmed by the ultraviolet-visible absorption spectra (UV-Vis). X-ray diffraction (XRD) measurements showed that element doping prevents the transition from anatase to rutile and increases the transition temperature. TiO2 was successfully doped due to the reduction of the chemical binding energy of Ti, as revealed by X-ray photoelectron spectroscopy (XPS). The degradation rates of NOX, CO, and CO2 in VE by Fe/N/Co–TiO2 NPs under visible light were 71.43%, 23.79%, and 21.09%, respectively. In contrast, under the same conditions, the degradation efficiencies of coating for VE decreased slightly. Moreover, the elementary properties of the coating, including pencil hardness, adhesive strength, water resistance, salt, and alkali resistance met the code requirement. The photocatalytic coating exhibited favorable reusability and durability, as shown by the reusability and exposure test.

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“…PC pavements containing photocatalysts have the potential to remove pollutants from the air and curb contamination in urban areas [69,70]. Similar to the photosynthesis in plants, photocatalytic compounds can be used to trap and absorb organic and inorganic particles in the air, removing harmful pollutants such as nitrogen oxides (NOX) [71] or polycyclic aromatic hydrocarbons that can be found in stormwater [69], among others [71,72]. Some studies have also addressed the photocatalytic degradation of NOX, obtaining promising results [70].…”

Section: Air Quality Improvementmentioning

confidence: 99%

Review of porous concrete as multifunctional and sustainable pavement

Elizondo-Martínez

Andrés‐Valeri

Jato-Espino

et al. 2020

Journal of Building Engineering

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Porous Concrete (PC) pavements have been gaining a lot of attention in recent years because of the many advantages they can provide, especially in urban areas because they are easy to lay and capable of mitigating the problems caused by conventional roads. For this reason, PC pavements have been recognized as one of the best solutions to reduce water and air environmental impacts, as well as to increase driver safety. Nevertheless, their use is still limited, since there are not enough studies addressing them comprehensively, mainly because of the lack of awareness about all their potential benefits. Therefore, this paper reviews the main properties that PC mixtures can provide for designing multifunctional and sustainable pavements. To this end, the investigations undertaken during the last decade (2009-2018) in this topic were analyzed in detail, identifying the regions where they are being most widely studied, analyzing and predicting their future potential developments. Results revealed that mechanical and hydraulic capacity are the two main properties studied in PC pavements. In addition, a predicted growth for 2019-2030 of 2.51% (4.29 PC publications per year) is expected.

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Effect of weathering and traffic exposure on removal of nitrogen oxides by photocatalytic coatings on roadside concrete structures

Cited by 11 publications

References 29 publications

De-pollution efficacy of photocatalytic roofing granules

De-pollution efficacy of photocatalytic roofing granules

The Photocatalytic Degradation of Vehicle Exhausts by an Fe/N/Co–TiO2 Waterborne Coating under Visible Light

Review of porous concrete as multifunctional and sustainable pavement

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