da Costa Filho Batuira M, Silva Gabriela V, Boaventura Rui A R, Dias Madalena M, Lopes José C B, Vilar Vítor J P
Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; CNPq - National Council of Technological and Scientific Development, Brazil.
INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
Sci Total Environ. 2019 Oct 15;687:1357-1368. doi: 10.1016/j.scitotenv.2019.05.365. Epub 2019 May 29.
The present work evaluates ozone driven processes (O, O/UVC, O/TiO/UVA) in the NETmix mili-photoreactor, as a cost-effective alternative for the removal of volatile organic compounds (VOCs) from air streams, using n-decane as a model pollutant. The network of channels and chambers of the mili-photoreactor was coated with a TiO-P25 thin film, resulting in a catalyst coated surface per reactor volume of 990 m m. Ozone and n-decane streams were fed to alternate chambers of the mili-photoreactor, promoting a good contact between O/n-decane/catalyst. Initially, direct reaction between n-decane and ozone (ozonation) was assessed for different O/n-decane (O/dec) feed molar ratios and total feed flow rates. Under the best conditions, ozonation process achieved total n-decane conversion (below the limit of detection), yielding a reaction rate (r) of 6.8 μmol min or 6.7 mmol m s. However, the low reactivity of ozone with the degradation by-products resulted in a quite poor mineralization (~10%). For the O/UVC system, an increase on relative humidity from 7 to 40% slight improved the n-decane oxidation rate, mainly associated with the generation of HO from the reaction of active oxygen radicals (O) and water molecules. A strong synergistic effect was observed when coupling TiO/UVA photocatalysis with ozonation (O/TiO/UVA), enhancing substantially the mineralization of n-decane molecules up to 100% under O/dec feed molar ratio of 15, photonic flux of 2.67 ± 0.03 J s and a residence time of 2.0 s. Different reaction intermediates were detected for O, TiO/UVA and O/TiO/UVA oxidative systems, indicating the participation of different oxidant species (O, HO, O, etc.).
本研究评估了NETmix微型光反应器中臭氧驱动的过程（O、O/UVC、O/TiO/UVA），该过程以正癸烷作为模型污染物，是一种从气流中去除挥发性有机化合物（VOCs）的经济高效的替代方法。微型光反应器的通道和腔室网络涂有TiO-P25薄膜，每个反应器体积的催化剂涂层表面积为990 m²。臭氧和正癸烷气流被输送到微型光反应器的交替腔室中，促进了O/正癸烷/催化剂之间的良好接触。最初，针对不同的O/正癸烷（O/dec）进料摩尔比和总进料流速，评估了正癸烷与臭氧之间的直接反应（臭氧化）。在最佳条件下，臭氧化过程实现了正癸烷的完全转化（低于检测限），反应速率（r）为6.8 μmol/min或6.7 mmol/m²·s。然而，臭氧与降解副产物的低反应性导致矿化程度相当低（约10%）。对于O/UVC系统，相对湿度从7%增加到40%略微提高了正癸烷的氧化速率，这主要与活性氧自由基（O）与水分子反应生成HO有关。当将TiO/UVA光催化与臭氧化（O/TiO/UVA）耦合时，观察到了强烈的协同效应，在O/dec进料摩尔比为15、光子通量为2.67±0.03 J/s和停留时间为2.0 s的条件下，正癸烷分子的矿化率大幅提高至100%。对于O、TiO/UVA和O/TiO/UVA氧化系统，检测到了不同的反应中间体，表明不同的氧化剂物种（O、HO、O等）参与了反应。
