Aix Marseille Univ , CNRS, LCE, UMR 7376 , 13331 , Marseille , France.
Aix Marseille Univ , CNRS, ICR, UMR 7273 , 13297 , Marseille , France.
Environ Sci Technol. 2018 Oct 2;52(19):11328-11337. doi: 10.1021/acs.est.8b03865. Epub 2018 Sep 19.
Photocatalytic paints based on titanium dioxide (TiO) nanoparticles represent a promising treatment technology for cleaning the air at our dwellings. A few studies have shown that instead of elimination of harmful indoor air pollutants the production of carbonyl compounds occurs from the photocatalytic paints. Herein, we report unexpectedly high concentrations of volatile organic compounds (VOCs) released upon irradiation of photocatalytic paints which are meant to clean the air at our dwellings. The concentrations of the VOCs were measured continuously and online by PTR-ToF-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) connected to a well-established flow tube photoreactor. The PTR-ToF-MS analysis revealed the presence of 52 ions in the mass range between 20 and 490 amu, among which 43 have been identified. In particular very high emission rates were estimated of two relevant indoor air pollutants, formaldehyde and acetaldehyde as 355 μg h and 257 μg h for 1 m, respectively. We suggest a detailed reaction mechanism responsible for the production of these harmful indoor air pollutants (formaldehyde and acetaldehyde, among the others). The hydroxyl radicals (OH) formed upon activation of TiO, react with the organic constituent (butyl acrylate and vinyl acetate) of the paint binder lead to generation of an important number of organic compounds. We demonstrate that the TiO quantity and the organic content of the binder is of paramount importance with respect to the formation of VOCs, which should be considered for future optimization of this air remediation technology based on TiO nanoparticles.
基于二氧化钛 (TiO) 纳米粒子的光催化涂料代表了一种有前途的清洁我们居住环境空气的处理技术。一些研究表明，光催化涂料不是消除有害的室内空气污染物，而是会产生羰基化合物。在此，我们报告了出人意料的高浓度挥发性有机化合物 (VOCs)，这些 VOCs 在照射旨在清洁我们居住环境空气的光催化涂料时会释放出来。通过 PTR-ToF-MS（质子转移反应-飞行时间质谱）在线连续测量 VOCs 的浓度，该仪器连接到一个成熟的流动管光反应器。PTR-ToF-MS 分析揭示了在 20 到 490 amu 的质量范围内存在 52 个离子，其中 43 个已经被鉴定。特别是，对于两种相关的室内空气污染物甲醛和乙醛，分别估计了非常高的排放速率，分别为 355 μg h 和 257 μg h （对于 1 m 而言）。我们提出了一个详细的反应机制，该机制负责产生这些有害的室内空气污染物（甲醛和乙醛等）。在 TiO 激活过程中形成的羟基自由基 (OH) 与涂料粘合剂中的有机成分（丙烯酸丁酯和醋酸乙烯酯）反应，导致产生大量有机化合物。我们证明，TiO 的数量和粘合剂的有机含量对于 VOCs 的形成至关重要，这应该在未来基于 TiO 纳米粒子的空气修复技术的优化中加以考虑。
