Instituto de Investigación e Ingeniería Ambiental (IIIA), Universidad Nacional de San Martin (UNSAM), CONICET, 3iA, Campus Miguelete, Av. 25 de Mayo y Francia, 1650, San Martín, Provincia de Buenos Aires, Argentina.
Environ Sci Pollut Res Int. 2020 Aug;27(23):28469-28479. doi: 10.1007/s11356-019-06045-6. Epub 2019 Aug 3.
The aim of this work is to study the byproducts formed as a result of the photocatalytic process under different conditions of light wavelength and photocatalyst doping, rendering valuable information about the fate of pollutants for water treatment applications. Salicylic acid was selected as a model emerging pollutant and powders of nitrogen-doped titanium dioxide (N-TiO) and TiO were prepared by the sol-gel process, using TiO P-25 Degussa as benchmark. Two light sources, UVA fluorescent tubes (372 nm) and blue LEDs (462 nm), were employed for photolysis and photocatalysis experiments. Transformation products formed during the process were studied by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Major differences were found in the amount and identity of the transformation products due to the different light sources, detecting similar transformation products among the studied catalysts. Under UVA light, hydroxylated and carbonylated byproducts were the first intermediates to reach maximum abundances whereas presumed ring opening products were the last ones. On the other hand, under blue LED illumination byproducts accumulated with decreased mineralization. Photocatalytic degradation pathways were proposed based on the findings.
本工作旨在研究在不同波长的光和光催化剂掺杂条件下光催化过程中形成的副产物，为水处理应用中污染物的归宿提供有价值的信息。选择水杨酸作为新兴污染物的模型，采用溶胶-凝胶法制备氮掺杂二氧化钛（N-TiO）和 TiO 粉末，以 TiO P-25 Degussa 为基准。使用两种光源，UVA 荧光管（372nm）和蓝色 LED（462nm）进行光解和光催化实验。通过高效液相色谱-质谱联用（HPLC-MS）研究了过程中形成的转化产物。由于光源不同，检测到在研究的催化剂中存在相似的转化产物，因此在产物的数量和种类上存在显著差异。在 UVA 光下，羟基化和羰基化副产物是达到最大丰度的第一中间体，而假定的开环产物是最后一种。另一方面，在蓝色 LED 照射下，副产物的积累伴随着矿化度的降低。根据研究结果提出了光催化降解途径。
