title: Photocatalysis of Volatile Organic Compounds in water: Towards a deeper understanding of the role of cyclodextrins in the photodegradation of toluene over titanium dioxide.
abstract: OBJECTIVE
  Cyclodextrin-assisted photodegradation of toluene was investigated in water in the presence of a photo-irradiated commercial titanium dioxide photocatalyst. It was expected that cyclodextrins could form water-soluble supramolecular host/guest complexes with the toluene and thus promote the approach of the pollutant on the TiO2 surface and enhance the phototocatalytic oxidation efficiency.
  
  
  METHODS
  Photodegradation kinetics of toluene were investigated under UV-C and near-visible light radiation in aqueous suspensions of TiO2. Impact of cyclodextrin (CD) on the photocatalytic efficiency of TiO2 was evaluated with different cyclodextrins: α-CD, β-CD, γ-CD and RAME-β-CD. Host-guest association constants were determined by static headspace gas chromatography and affinity of cyclodextrins for the TiO2 surface by isothermal adsorption studies. Issue of the cyclodextrin stability during the degradation process was examined using Total Organic Carbon, NMR and MALDI-TOF analyses.
  
  
  RESULTS
  Toluene could be fully mineralized by TiO2 in water within hours, even if the presence of cyclodextrin caused a delay in the photodegradation process. The chemical nature of cyclodextrins was found to exert a significant influence on the extent of inhibitory effect, which was discussed in terms of balance between solubilization efficiency, substrate protection and coverage of active sites of TiO2 by competitive adsorption. The cyclodextrin degradation was also studied and discussed.
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Lannoy
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Kania
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France.
authors.forename: Rudina
authors.initials: R
authors.lastname: Bleta
authors.affiliation: Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), F-59140 Dunkerque, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Fourmentin
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France. Electronic address: cecile.machut@univ-artois.fr.
authors.forename: Cécile
authors.initials: C
authors.lastname: Machut-Binkowski
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Monflier
authors.affiliation: Univ. Artois, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens, France; CNRS, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), Lille F-59000, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Ponchel
keywords: Adsorption; Cyclodextrins; Inclusion complex; Photocatalysis; Toluene