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Sci Total Environ

Title:		"Ozonation and ozone-enhanced photocatalysis for VOC removal from air streams: Process optimization, synergy and mechanism assessment"
Author(s):		da Costa Filho BM; Silva GV; Boaventura RAR; Dias MM; Lopes JCB; Vilar VJP;
Address:		"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. 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. 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. Electronic address: vilar@fe.up.pt"
Journal Title:		Sci Total Environ
Year:		2019
Volume:		20190529
Issue:
Page Number:		1357 - 1368
DOI:		10.1016/j.scitotenv.2019.05.365
ISSN/ISBN:		1879-1026 (Electronic) 0048-9697 (Linking)
Abstract:		"The present work evaluates ozone driven processes (O(3), O(3)/UVC, O(3)/TiO(2)/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(2)-P25 thin film, resulting in a catalyst coated surface per reactor volume of 990?ª+m(2)?ª+m(-3). Ozone and n-decane streams were fed to alternate chambers of the mili-photoreactor, promoting a good contact between O(3)/n-decane/catalyst. Initially, direct reaction between n-decane and ozone (ozonation) was assessed for different O(3)/n-decane (O(3)/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(dec)) of 6.8?ª+mumol?ª+min(-1) or 6.7?ª+mmol?ª+m(-3)(reactor) s(-1). However, the low reactivity of ozone with the degradation by-products resulted in a quite poor mineralization (~10%). For the O(3)/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(2)/UVA photocatalysis with ozonation (O(3)/TiO(2)/UVA), enhancing substantially the mineralization of n-decane molecules up to 100% under O(3)/dec feed molar ratio of 15, photonic flux of 2.67?ª++/-?ª+0.03?ª+J?ª+s(-1) and a residence time of 2.0?ª+s. Different reaction intermediates were detected for O(3), TiO(2)/UVA and O(3)/TiO(2)/UVA oxidative systems, indicating the participation of different oxidant species (O(3), HO, O, etc.)"
Keywords:		Air decontamination Ozone Photocatalytic ozonation Process intensification VOCs;
Notes:		"PubMed-not-MEDLINEda Costa Filho, Batuira M Silva, Gabriela V Boaventura, Rui A R Dias, Madalena M Lopes, Jose C B Vilar, Vitor J P eng Netherlands 2019/08/16 Sci Total Environ. 2019 Oct 15; 687:1357-1368. doi: 10.1016/j.scitotenv.2019.05.365. Epub 2019 May 29"