Benzene is a toxic, volatile organic pollutant and does great harm to both human beings and atmospheric environment. Vacuum ultraviolet (VUV) photooxidation, an emerging efficient process for the oxidation of pollutants, was used to destroy gaseous benzene. The effect of key operating parameters such as relative humidity, residence time, initial benzene concentration, and reaction temperature was investigated to study the performance and mechanism of benzene VUV photooxidation. Results indicated that vapor can greatly improve benzene removal efficiency and inhibit ozone formation since it can be used by energetic VUV photons to produce hydroxyl radicals (•OH), highly reactive for benzene oxidation. The increase of residence time and decrease of initial benzene concentration can greatly improve both the removal efficiency and mineralization rate of benzene. •OH is mainly responsible for benzene oxidation in the VUV photooxidation process.
Get full access to this article
View all access options for this article.
References
1.
AgarwalS.K., and SpiveyJ.J. (1993). Economic effects of catalyst deactivation during VOC oxidation. Environ. Prog., 12, 182.
2.
AlapiT., and DombiA. (2007). Direct VUV photolysis of chlorinated methanes and their mixtures in an oxygen stream using an ozone producing low-pressure mercury vapour lamp. Chemosphere, 67, 693.
3.
AtkinsonR. (1994). Gas-phase tropospheric chemistry of organic compounds. J. Phys. Chem. Ref. Data, 55, Monograph 2, 1.
4.
AtkinsonR. (2000). Atmospheric chemistry of VOCs and NOx. Atmos. Environ., 34, 2063.
5.
AtkinsonR., BaulchD., CoxR., CrowleyJ., HampsonR., HynesR., JenkinM., RossiM., and TroeJ. (2004). Evaluated kinetic and photochemical data for atmospheric chemistry: volume I-gas phase reactions of Ox, HOx, NOx and SOx species. Atmos. Chem. Phys., 4, 1461.
6.
BergonzoP., and BoydI.W. (1993). Low pressure photodeposition of silicon nitride films using a xenon excimer lamp. Appl. Phys. Lett., 63, 1757.
7.
ChenJ.-M., ChengZ.-W., JiangY.-F., and ZhangL.-L. (2010). Direct VUV photodegradation of gaseous α-pinene in a spiral quartz reactor: intermediates, mechanism, and toxicity/biodegradability assessment. Chemosphere, 81, 1053.
8.
DaifullahA., and GirgisB. (2003). Impact of surface characteristics of activated carbon on adsorption of BTEX. Colloid Surf. A., 214, 181.
9.
DarracqG., CouvertA., CouriolC., DumontE., AmraneA., and Le CloirecP. (2012). Activated sludge acclimation for hydrophobic VOC removal in a two-phase partitioning reactor. Water Air Soil. Pollut., 223, 3117.
10.
DriessenM., MillerT., and GrassianV. (1998). Photocatalytic oxidation of trichloroethylene on zinc oxide: characterization of surface-bound and gas-phase products and intermediates with FT-IR spectroscopy. J. Mol. Catal. A Chem., 131, 149.
11.
FarhadianM., DuchezD., VachelardC., and LarrocheC. (2008). BTX removal from polluted water through bioleaching processes. Appl. Biochem. Biotech., 151, 295.
12.
HashemT., ZirlewagenM., and BraunA. (1997). Simultaneous photochemical generation of ozone in the gas phase and photolysis of aqueous reaction systems using one VUV light source. Water Sci. Technol., 35, 41.
13.
JeongJ., SekiguchiK., LeeW., and SakamotoK. (2005). Photodegradation of gaseous volatile organic compounds (VOCs) using TiO2 photoirradiated by an ozone-producing UV lamp: decomposition characteristics, identification of by-products and water-soluble organic intermediates. J. Photochem. Photobiol. A., 169, 279.
14.
KangM., KimB.-J., ChoS.M., ChungC.-H., KimB.-W., HanG.Y., and YoonK.J. (2002). Decomposition of toluene using an atmospheric pressure plasma/TiO2 catalytic system. J. Mol. Catal. A Chem., 180, 125.
15.
KorologosC.A., NikolakiM.D., ZervaC.N., PhilippopoulosC.J., and PoulopoulosS.G. (2012). Photocatalytic oxidation of benzene, toluene, ethylbenzene and m-xylene in the gas-phase over TiO2-based catalysts. J. Photochem. Photobiol. A., 244, 24.
16.
KorologosC.A., PhilippopoulosC.J., and PoulopoulosS.G. (2011). The effect of water presence on the photocatalytic oxidation of benzene, toluene, ethylbenzene and m-xylene in the gas-phase. Atmos. Environ., 45, 7089.
17.
KosuskoM., MullinsM.E., RamanathanK., and RogersT. (1988). Catalytic oxidation of ground water stripping emissions. Environ. Prog., 7, 136.
18.
McGregorF., PiscaerP., and AietaE. (1988). Economics of treating waste gases from an air stripping tower using photochemically generated ozone. Ozone Sci. Eng., 10, 339.
19.
McKoyD.Y.V. (2003). Assignments in the electronic spectrum of water. Phys. Chem. Chem. Phys., 61, 75.
SleimanM., ConchonP., FerronatoC., and ChovelonJ.M. (2009). Photocatalytic oxidation of toluene at indoor air levels (ppbv): towards a better assessment of conversion, reaction intermediates and mineralization. Appl. Catal. B Environ., 86, 159.
22.
SundstromD., WeirB., and KleiH. (1989). Destruction of aromatic pollutants by UV light catalyzed oxidation with hydrogen peroxide. Environ. Prog., 8, 6.
23.
TaatjesC.A., OsbornD.L., SelbyT.M., MeloniG., TrevittA.J., EpifanovskyE., KrylovA.I., SirjeanB., DamesE., and WangH. (2010). Products of the benzene+O (3P) reaction. Atmos. Chem. Phys., 114, 3355.
24.
WangL., VienV.D., SuzukiK., SakuraiM., and KameyamaH. (2005). Preparation of anodised aluminium catalysts by an electrolysis supporting method for VOC catalytic combustion. J. Chem. Eng. Jpn., 38, 106.
25.
ZhangP., LiuJ., and ZhangZ. (2004). VUV photocatalytic degradation of toluene in the gas phase. Chem. Lett., 33, 1242.
26.
ZhaoW., YangY., DaiJ., LiuF., and WangY. (2013). VUV photolysis of naphthalene in indoor air: intermediates, pathways, and health risk. Chemosphere, 91, 1002.
