References of "Geens, Jérémy"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailHighly dispersed iron xerogel catalysts for p-nitrophenol degradation by photo-Fenton effects
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Zubiaur, Anthony ULg et al

in Microporous and Mesoporous Materials (2014), 197

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ... [more ▼]

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions. The EDAS/TEOS ratio strongly influences the texture of xerogel catalysts. The specific surface area and the micro- and mesoporous volume increase with this ratio. It seems that EDAS plays a nucleating agent role for silica particles and allows to anchor Fe-based moieties inside the silica network. Iron oxide nanoparticles of diameter 1-1.5 nm and Fe3+ ions result, encapsulated in silica particles with sizes of about 10-30 nm in diameter. The iron species was determined by Mössbauer spectroscopy and magnetometry measurements and only Fe3+ species were observed in xerogel catalysts. The Fenton and photo-Fenton effect of these catalysts were evaluated on the degradation of p-nitrophenol in aqueous media under different conditions. Results show that in the presence of H2O2, iron xerogel catalysts present a photo-Fenton effect, reaching 99 % of degradation after 24 h. [less ▲]

Detailed reference viewed: 34 (10 ULg)
Full Text
Peer Reviewed
See detailSynthesis, Surface characterization and photocatalytic activity of TiO2 supported on almond shell activated carbon
Omri, Abdessalem; Lambert, Stéphanie ULg; Geens, Jérémy ULg et al

in Journal of Materials Science & Technology (2014), 30(9), 894-902

Three types of photocatalysts were synthesized by metal organic chemical vapor deposition and impregnation methods using the almond shell activated carbon as support. These photocatalysts denoted by (TiO2 ... [more ▼]

Three types of photocatalysts were synthesized by metal organic chemical vapor deposition and impregnation methods using the almond shell activated carbon as support. These photocatalysts denoted by (TiO2/ASAC (V), TiO2/ASAC (I1) and TiO2/ASAC (I2)) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and nitrogen adsorptionedesorption isotherms. SEM observation shows that TiO2 was deposited on activated carbon surface. XRD results confirm that TiO2 existed in a mixture of anatase and rutile phases. The DRS spectra show the characteristic absorption edge of TiO2 at approximate 380 nm corresponding to the optical band gap of 3.26 eV. Besides, FTIR spectrum indicated the presence of (TieO) groups. The specific surface area of photocatalysts decreased drastically in comparison with the original activated carbon. The catalysts were very efficient for the photodegradation of total organic carbon (TOC) from industrial phosphoric acid solution under UV irradiation. The kinetics of photocatalytic TOC degradation was found to follow a pseudofirst- order model. The prepared TiO2/ASAC showed high photoactivity for the photodegradation of TOC in the following order: TiO2/ASAC (V) > TiO2/ASAC (I1) > TiO2/ASAC (I2) > ASAC > TiO2 (P25). [less ▲]

Detailed reference viewed: 8 (2 ULg)
Peer Reviewed
See detailHighly dispersed iron xerogel catalysts for p-nitrophenol degradation by photo-Fenton effects
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Zubiaur, Anthony ULg et al

Poster (2014, July)

Since the beginning of the industrial era, the various human activities have increased steadily, leading to a rapid technological development and a high population growth. Thus, the expansion of the ... [more ▼]

Since the beginning of the industrial era, the various human activities have increased steadily, leading to a rapid technological development and a high population growth. Thus, the expansion of the industry has heavily polluted the atmosphere, soil and water with negative consequences for humans and environment [1]. To decrease this pollution, it exists various treatment methods: chemical, physical and biological [2,3]. Among all these methods, a recent way of treatment is the degradation of pollutants in soils or waters by Fenton and photo-Fenton reactions [3] which use H2O2, iron-based compounds and UV light. In this way, several Fe2O3/SiO2 xerogel catalysts were synthesized by cogelation method by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions [4]. Five samples were synthesized: four samples with different percentage of iron (0.5, 1, 1.5 and 2.5 theoretical wt% confirmed by ICP-AES measurements), and a sample of pure silica. TEM pictures, nitrogen adsorption-desorption and mercury porosimetry measurements have established that EDAS plays a role of nucleating agent of silica particles [5,6] and allows to anchor iron particles inside silica network [4]. Indeed, it results iron nanoparticles of diameter 1-1.5 nm encapsulated in silica particles with sizes of about 10-30 nm in diameter. The species of iron was determined by Mössbauer spectroscopy and only Fe3+ ions were observed in xerogel catalysts. Then, the Fenton and photo-Fenton effect of these catalysts were evaluated on the degradation of p-nitrophenol (PNP) in aqueous medium in different conditions. Results show that Fe2O3/SiO2 xerogels present a photo-Fenton effect with H2O2, reaching with a sample 99 % of degradation after 24 h. [1] M. A. Khan, A. M. Ghouri, Environmental pollution: its effects on life and its remedies, Journal of Arts, Science & Commerce (Vol. 2), 2011, pg 276-285. [2] M. S. Kuyukina , I. B. Ivshina, Biology of rhodococcus: chapter 9, Springer, 2010, pg 232-256. [3] J. J. Pignatello, E. Oliveros, A. MacKay, Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry, Critical Reviews in Environmental Science and Technology (Vol. 36), 2006, pg 1-84. [4] B. Heinrichs, L. Rebbouh, J.W. Geus, S. Lambert, H.C.L. Abbenhuis, F. Grandjean, G.J. Long, J.-P. Pirard, R.A. van Santen, Iron (III) species dispersed in porous silica through sol-gel chemistry, Journal of Non-Crystalline Solids (Vol. 354), 2008, pg 665-672. [5] S. Lambert, C. Alié, J.-P. Pirard, B. Heinrichs, Study of textural properties and nucleation phenomenon in Pd/SiO2 , Ag/SiO2 and Cu/SiO2 cogelled xerogel catalysts, Journal of Non-Crystalline Solids (Vol. 342), 2004, pg 70-81. [6] B. Heinrichs, S. Lambert , N. Job , J.-P. Pirard, in "Catalyst Preparation: Science and Engineering, J. R. Regalbuto (Ed.)", CRC Press, Taylor & Francis Group, Boca Raton, 2007, p. 163-208. [less ▲]

Detailed reference viewed: 61 (19 ULg)
Full Text
Peer Reviewed
See detailPhotocatalytic degradation of phenol and benzoic acid using zinc oxide powders prepared by the sol-gel process
Benhebal, Hadj; Chaib, Messaoud; Salmon, Thierry ULg et al

in Alexandria Engineering Journal (2013), 52(3), 517-523

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray ... [more ▼]

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray diffraction and transmission electron microscopy. The Brunauer–Emmett–Teller surface area, pHpzc, and the band gap of the catalyst samples were also measured. The influence of various key parameters such as amount of photocatalyst, initial solution pH, and the initial concentration of phenol and benzoic acid was investigated. [less ▲]

Detailed reference viewed: 42 (5 ULg)
Full Text
Peer Reviewed
See detailPhotocatalytic degradation of phenol and benzoic acid using zinc oxide powders prepared by the sol-gel process
Benhebal, Hadj; Chaib, Messaoud; Salmon, Thierry ULg et al

in Alexandria Engineering Journal (2013), 52(3), 517-523

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray ... [more ▼]

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray diffraction and transmission electron microscopy. The Brunauer–Emmett–Teller surface area, pHpzc, and the band gap of the catalyst samples were also measured. The influence of various key parameters such as amount of photocatalyst, initial solution pH, and the initial concentration of phenol and benzoic acid was investigated. [less ▲]

Detailed reference viewed: 42 (5 ULg)
Full Text
Peer Reviewed
See detailSol-gel preparation of pure and doped TiO2 films for the photocatalytic oxidation of ethanol in air
Cimieri, Iolanda; Poelman, Hilde; Avci, Nursen et al

in Journal of Sol-Gel Science and Technology (2012), 63

Stable sols of TiO2 were synthesized by a non-aqueous sol-gel process using titanium (IV) isopropoxide (TTIP) as precursor. The microstructure, optical and morphological properties of the films obtained ... [more ▼]

Stable sols of TiO2 were synthesized by a non-aqueous sol-gel process using titanium (IV) isopropoxide (TTIP) as precursor. The microstructure, optical and morphological properties of the films obtained by spin-coating from the sol, and annealed at different temperatures, were investigated using SEM, TEM, diffuse reflectance spectroscopy (DRS) and ellipsometry. The crystalline structure of the films was characterized by X-ray diffraction and their photocatalytic activity was evaluated for the oxidation of ethanol in air. The influence of the calcination temperature, pre-heat treatment and the number of layers was studied. Simultaneous thermo-gravimetric and differential thermal analysis (TG/DTA) measurements were carried out to ascertain the thermal decomposition behavior of the precursors. In order to obtain a higher photoresponse in the visible region, a series of vanadium-, niobium- and tantalum-doped TiO2 catalysts was synthesized by the same sol-gel method. For V doping two different precursors, a vanadium alkoxide and V2O5, were used. The effect on the crystallization and photocatalytic activity of the doped TiO2 films was investigated. Furthermore, to identify the effective composition of the samples, they were characterized by X-ray photoelectron spectroscopy (XPS) and the surface area of the powders was measured by N2 adsorption. The 10wt.% doped catalysts exhibit high photocatalytic activity under visible light and among them the best performance was obtained for the sample containing Ta as dopant. The crystallite sizes are closely related to the photocatalytic activity. [less ▲]

Detailed reference viewed: 56 (13 ULg)