Applied Catalysis B: Environmental, Vol.179, 78-87, 2015
Comparison of kinetics of acetone, heptane and toluene photocatalytic mineralization over TiO2 microfibers and Quartzel (R) mats
The kinetic parameters for VOCs (acetone, toluene, heptane) mineralization of lab-extruded pure TiO2 fibers prepared under easily scalable conditions were compared with those of a commercial photocatalytic media from Saint-Gobain, Quartzel (R), under identical conditions. A flow-through recirculating reactor loop with variable LEDs irradiation at 365 nm was specially designed. All the experiments were carried out in a continuous recycle mode. Both types of fibers were very efficient for acetone and heptane mineralization. At 20% relative humidity (RH), the reaction rates were higher with the commercial media, whereas at 60% RH the catalysts displayed equal activity for acetone conversion. Toluene mineralization was much faster on these lab-made fibers than on Quarztel (R), which was more sensitive to poisoning by reaction by-products. At 20% relative humidity, with the lab-made TiO2 fibers, typical quantum efficiencies were, respectively, 0.0106 and 0.0027 for acetone and heptane (100 ppmV initial concentration) and 0.0024 for toluene (200 ppmV initial concentration) while these quantum efficiencies were 0.0358, 0.0133 and 0.0011 with expanded Quartzel fibers under the same conditions. These results evidence a clear difference in the VOCs, water and polar by-products adsorption between these two kinds of fibers. These newly developed fibers can be produced at an industrial scale with a proven efficiency for VOCs degradation and mineralization. Since they are less sensitive to humidity than the commercial fibers, they could be most useful under actual ambient air conditions. These fibers present a good alternative to other commercially available photocatalytic media for gas phase purification. (C) 2015 Elsevier B.V. All rights reserved.