Kinetic study of air treatment by photocatalytic paints under indoor radiation source: Influence of ambient conditions and photocatalyst content

• Published in: Applied catalysis. B, Environmental Environmental, 2020-07, Vol.268, p.118694, Article 118694
• Main Authors: Salvadores, F., Alfano, O.M., Ballari, M.M.
• Format: Article
• Language: English
• Subjects: Acetaldehyde; Air decontamination; Air pollution; Building materials; Construction materials; Contaminants; Decontamination; Efficiencies; Intermediates; Kinetic study; Oxidation; Paints; Photocatalysis; Photocatalysts; Photocatalytic paints; Photon absorption; Pollution control; Radiation; Reaction intermediates; Reaction kinetics; Titanium dioxide
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.118694

[Display omitted] •Intrinsic kinetic model for indoor air decontamination by photocatalytic paints.•Minimum irradiation level needed to observe photocatalytic reaction.•Determination of useful wavelength range according to photocatalyst bandgap.•New parameter to correlate active area with TiO2 amount and agglomeration in paint.•Quantum efficiency decrease with higher amount of photocatalyst in paint. Photocatalytic building materials constitute a promising technology to control air pollution, although intrinsic kinetics is needed for prediction of decontamination processes. Herein, the kinetic study of acetaldehyde oxidation was carried out applying photocatalytic paints under normal indoor illumination source and different ambient conditions. An intrinsic kinetic model for the main contaminant and reaction intermediates was proposed as a function of the Local Superficial Rate of Photon Absorption, which was evaluated for paints containing different amounts of carbon doped TiO2. A novel parameter to account for the relationship between photocatalytic active area, TiO2 amount and particles agglomeration in the paints was proposed. Also, based on the model predictions and the photocatalyst bandgap energy a spectral radiation analysis was performed determining the maximum wavelength at which the photocatalyst is active. Finally, the quantum and photonic efficiencies were calculated and the effect of operating conditions on these efficiencies was analyzed.