TiO2 Macroscopic Fibers Bearing Outstanding Photocatalytic Properties Obtained through an Integrative Chemistry-Based Scale-Up Semi-Industrial Process

2015 ◽  
Vol 1804 ◽  
pp. 7-12
Author(s):  
Natacha Kinadjian ◽  
Mickael le Bechec ◽  
Wilfrid Neri ◽  
Philippe Poulin ◽  
Sylvie Lacombe ◽  
...  

ABSTRACTIn here we depict the morphogenesis and associated properties of TiO2-based macroscopic fibers designed for the photodecomposition of volatile organic compounds (VOC). We employed a continuous industrially scalable extrusion-based process making the use of hybrid sols of amorphous titania nanoparticles, polyvinyl alcohol (PVA) and occasionally latex nanoparticles. This process allowed for the continuous generation of hybrid TiO2/latex/PVA or TiO2/PVA macroscopic fibers. Upon thermal treatment, biphasic porous fibers are obtained containing the anatase phase of TiO2 with 10-15% of brookite. These fibers, which can be manufactured under several hundred meter of length, are offering significantly improved phototocatalytic efficiency now comparable to the commercial Quartzel®PCO photocatalyst for gas-phase acetone mineralization.

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 549
Author(s):  
Maarja Kask ◽  
Marina Krichevskaya ◽  
Sergei Preis ◽  
Juri Bolobajev

The treatment of wastewaters containing hazardous volatile organic compounds (VOCs) requires the simultaneous treatment of both water and air. Refractory toluene, extensively studied for its removal, provides a basis for the comparison of its abatement methods. The oxidation of aqueous toluene by gas-phase pulsed corona discharge (PCD) in combination with the subsequent photocatalytic treatment of exhaust air was studied. The PCD treatment showed unequalled energy efficiencies in aqueous and gaseous toluene oxidation, reaching, respectively, up to 10.5 and 29.6 g·kW−1·h−1. The PCD exhaust air contained toluene residues and ozone in concentrations not exceeding 0.1 and 0.6 mg·L−1, respectively. As a result of the subsequent photocatalytic treatment, both airborne residues were eliminated within a contact time with TiO2 as short as 12 s. The results contribute to the possible application of the studied approach in closed-loop energy-saving ventilation systems.


2008 ◽  
Vol 42 (34) ◽  
pp. 7844-7850 ◽  
Author(s):  
Aikaterini K. Boulamanti ◽  
Christos A. Korologos ◽  
Constantine J. Philippopoulos

2014 ◽  
Vol 14 (8) ◽  
pp. 12121-12165 ◽  
Author(s):  
M. I. Jacobs ◽  
W. J. Burke ◽  
M. J. Elrod

Abstract. Isoprene, the most abundant non-methane volatile organic compound (VOC) emitted into the atmosphere, is known to undergo gas phase oxidation to form eight different hydroxynitrate isomers in "high NOx" environments. These hydroxynitrates are known to affect the global and regional formation of ozone and secondary organic aerosol (SOA), as well as affect the distribution of nitrogen. In the present study, we have synthesized three of the eight possible hydroxynitrates: 4-hydroxy-3-nitroxy isoprene (4,3-HNI) and E/Z-1-hydroxy-4-nitroxy isoprene (1,4-HNI). Oxidation of the 4,3-HNI isomer by the OH radical was monitored using a flow tube chemical ionization mass spectrometer (FT-CIMS), and its OH rate constant was determined to be (3.64 ± 0.41) × 10−11 cm3 molecule−1 s−1. The products of 4,3-HNI oxidation were monitored, and a mechanism to explain the products was developed. An isoprene epoxide (IEPOX) – a species important in SOA chemistry and thought to originate only from "low NOx" isoprene oxidation – was found as a minor, but significant product. Additionally, hydrolysis kinetics of the three synthesized isomers were monitored with NMR. The bulk, neutral solution hydrolysis rate constants for 4,3-HNI and the 1,4-HNI isomers were (1.59±0.03 × 10−5 s−1 and (6.76 ± 0.09) × 10−3 s−1, respectively. The hydrolysis reactions of each isomer were found to be general acid-catalyzed. The reaction pathways, product yields and atmospheric implications for both the gas phase and aerosol-phase reactions are discussed.


The Analyst ◽  
2010 ◽  
Vol 135 (2) ◽  
pp. 306 ◽  
Author(s):  
Leonard A. Dillon ◽  
Victoria N. Stone ◽  
Laura A. Croasdell ◽  
Peter R. Fielden ◽  
Nicholas J. Goddard ◽  
...  

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