Removal of trace level aqueous mercury by adsorption and photocatalysis on silica–titania composites

Byrne, Heather E.; Mazyck, David W.

doi:10.1016/j.jhazmat.2009.05.055

Cited by 55 publications

(23 citation statements)

References 20 publications

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“…[14]The photocatalytic activity of mesoporous titania and titania-silica composites synthesized by the sol-gel method is recently a hot topic of materials research. [15,16,17,18,19,20,21,22]Pure titania aerogels were shown to be more efficient photocatalysts than titania-silica aerogels.However, it should be emphasized, thatcomposite aerogels usually lack the structural homogeneity of TiO 2 and SiO 2 phases on the atomic scale. [23,24] In other words, some micro-or nanocrystalline TiO 2 , usually in the form of anatase, is always present dispersed in the structure, and this crystalline phase is responsible for the photocatalytic effect.In this work we present a family of titaniasilica aerogels in which no crystalline TiO 2 can be detected by X-ray diffraction methods.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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Abstract. Titania-silica composite aerogels with 16 -29% Ti-content by the mass were synthesized by the sol-gel method from different Ti-precursors, and calcined at 500°C. These aerogels are highly amorphous as no crystalline TiO 2 phase can be detected in them by X-ray diffraction methods, and show the dominating presence of either mesopores or macropores.The incorporation of Ti into the silica structure is shown by the appearance of characteristic IR transitions of Si-O-Ti vibrations.The characteristic band-gap energies ofthe different aerogelsare estimated to be between 3.6 and 3.9 eV from UV reflection spectra. Band-gap energy decreases with decreasing pore-size. When suspended in solution,even these highly amorphous aerogels accelerate the photodegradation of salicylic acid and methylene blue compared to simple photolysis. Kinetic experiments were conducted under illumination, and also in the dark to study the adsorption of the substrates onto the suspended aerogels.We assume that the fast in-situadsorption of the organic substratesmask the suspended aerogel particles from UV photons,which reduces the rate of photocatalysis. We managed to mathematically separate the parallelprocesses of photocatalysis and adsorption, and develop a simple kinetic model to describe the reaction system.

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Section: Introductionmentioning

confidence: 99%

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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“…The photocatalytic activity of nanosilica/titania composites have been studied more widely and thoroughly [57][58][59][60][61][62][63][64][65][66][67][68] than MO-doped SiO 2 /TiO 2 (M: Cu or Ni) systems.…”

Section: Fig 1 Energy Level (N) Distribution For Differentmentioning

confidence: 99%

Band-Gap Change and Photocatalytic Activity of Silica/Titania Composites Associated with Incorporation of CuO and NiO

Nazarkovsky¹,

Гунько²,

Wójcik³

et al. 2015

Him. Fiz. Tehnol. Poverhni

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“…Lastly, it has recently been suggested that the adsorption of inorganic anions can be more successful than their photocatalytic oxidation. Byrne and Mazyck (2009) applied sol-gel derived silica-titania composites to remove trace level mercury (100 μgdm −3 ) from aqueous solutions by adsorption-photocatalysis and compared the removal efficiency with the precursors namely silica and Degussa P25 TiO 2 . Under dark adsorption conditions approximately 90 % removal of mercury was realised with the silica-titania composites, which was comparable to that of Degussa P25.…”

Section: Adsorption-photocatalysismentioning

confidence: 99%

Perspectives and Advances in Photocatalysis

Gaya

2013

Heterogeneous Photocatalysis Using Inorganic Semiconductor Solids

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Interest in heterogeneous photocatalysis has heightened in the past 40 years, underscoring several perspectives and advances. A collection of applications including solar to fuel cells, intelligent ink and remote photocatalysis have been closely examined. As an emerging panacea for the treatment of recalcitrant pollutants, heterogeneous photocatalytic degradation has been highlighted with specific reference to synthetic aliphatic and aromatic organic substances. What's more, various treatment technologies for integration with photocatalytic degradation have been outlined.

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Removal of trace level aqueous mercury by adsorption and photocatalysis on silica–titania composites

Cited by 55 publications

References 20 publications

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Band-Gap Change and Photocatalytic Activity of Silica/Titania Composites Associated with Incorporation of CuO and NiO

Perspectives and Advances in Photocatalysis

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