Synthesis of size-controlled silica-supported TiO2 photocatalysts

Grieken, Rafael van; Aguado, J.; López-Muñoz, Marı́a José; Marugán, Javier

doi:10.1016/s1010-6030(02)00058-8

Cited by 193 publications

(119 citation statements)

References 18 publications

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“…To overcome these drawbacks, immobilized photocatalysts are usually recommended. Photocatalysts could be immobilized on various supports such as glasses (Sabate et al, 1992;Kim et al, 1995;Fernandez et al, 1995;Wang et al, 1998;Piscopo et al, 2000;Sakthivel et al, 2002;Neti et al, 2010), tellerette packings (Mehrvar et al, 2002), silica (Van Grieken et al, 2002;Ding et al, 2001;Xu et al, 1999;Alemany et al, 1997;López-Muñoz et al, 2005;Marugán et al, 2006), polymers (Kasanen et al, 2009), and clays . The analysis and design of photochemical reactors have received increasing interests in chemical engineering recently.…”

Section: Photoreactor Designmentioning

confidence: 99%

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Mohajerani¹,

Mehrvar²,

Ein‐Mozaffari³

2012

Applied Computational Fluid Dynamics

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Section: Photoreactor Designmentioning

confidence: 99%

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Mohajerani¹,

Mehrvar²,

Ein‐Mozaffari³

2012

Applied Computational Fluid Dynamics

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“…Table 1 summarises the main textural properties and titanium dioxide crystal sizes of both Degussa P25 TiO 2 and the titania-silica photocatalyst. More details about the synthesis and characterization of these materials can be found elsewhere (22,23).…”

Section: Catalystsmentioning

confidence: 99%

Photocatalytic gold recovery from spent cyanide plating bath solutions

et al. 2005

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Gold-cyanide compounds represent the gold-containing chemicals most widely used in mining and electroplating industries. Despite many efforts focused on the substitution of cyanide salts by less toxic compounds, no successful alternatives have been found. The unique complexing capabilities of cyanide ions in aqueous solutions make these compounds the best choice for the heap leaching process in the gold mining sites or for gold plating applications (1).Wastewater effluents of these processes show significant concentrations of gold-cyanide complexes (2) that, due to its high stability, are very difficult to remove using the conventional oxidation technologies for cyanide degradation (3). Recovery of the gold present in the spent plating bath solutions, a desirable process from an economical standpoint, is currently carried out mainly by electrolysis and ion exchange processes.Some research groups (4-8) have shown the viability of the photochemical deposition and recovery of metallic gold from aqueous solutions of chloride species like AuCl 3 and AuCl 4 -in the presence of titania. These species are considered easy to reduce, due to their reduction potential of E 0 = +1.0 V NHE (NHE, normal hydrogen electrode), whereas the value of the reduction potential in oxygenated systems for Au(CN) 2 -is E 0 = -0.6 V NHE. However, to the best of our knowledge, there are no references in the literature about the TiO 2 -assisted photocatalytic decomposition of gold-cyanide complexes. Serpone et al. (6) reported the only work in which gold was deposited from air-equilibrated solutions prepared by mixture of NaCN and AuCl 3 ·3H 2 O. No trials for characterization of the gold-cyanide complexes that could be formed in the system were done. The goal of their work was to investigate the disposal of free CN -by oxidation with peroxides prior to irradiation of the solutions in the presence of TiO 2 . The fast oxidation of free cyanides avoided the formation of gold-cyanide complexes thus allowing Au(III) reduction on irradiated TiO 2 .On the other hand, the photocatalytic processes have shown a high efficiency for the oxidation of free cyanides (9,10), iron cyanocomplexes (11,12) and copper cyanocomplexes (13).In this work, a new procedure for gold recovery from solutions containing gold-cyanide complexes by using TiO 2 -based semiconductor materials is reported. The photocatalytic treatment performed in the absence of oxygen leads to the reduction of gold to the metallic state and increases the availability of cyanide for subsequent oxidation treatment (14).

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“…These support materials include glass fibres [13,14] , porous silica [15] , silica gel [16] , amorphous silica nanoparticles [17] , carbon particles [18,19] , and zeolites [20] .…”

Section: Introductionmentioning

confidence: 99%

Sand Supported Mixed‐Phase TiO₂ Photocatalysts for Water Decontamination Applications

Hanaor

Sorrell

2013

Adv Eng Mater

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Abstract:Using an organometallic precursor, TiO 2 coatings were fabricated on surfaces of quartz, zircon and rutile sands. X-ray Diffraction, X-ray Fluorescence, UV-Vis spectroscopy and surface area measurement were used to characterise support materials. The phase composition and morphology of the coatings were characterised by laser Raman spectroscopy and SEM respectively. A packed bed reactor was used to study the inactivation of Escherichia coli in recirculating water by the supported photocatalysts. It was found that the sand grains were well coated with a homogenous layer of TiO 2 and coatings were well adhered, exhibiting a mixed anatase-rutile composition after firing at 850°C.Photocatalytic activity was highest in coatings applied to quartz sand, although sterilisation of the recirculating water was not achieved with any of the materials investigated. The advantages of quartz as a TiO 2 photocatalyst support material are likely a result of this material's higher purity and optical transmittance. Potential enhancement through Si doping cannot be ruled out.

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Synthesis of size-controlled silica-supported TiO2 photocatalysts

Cited by 193 publications

References 18 publications

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Photocatalytic gold recovery from spent cyanide plating bath solutions

Sand Supported Mixed‐Phase TiO₂ Photocatalysts for Water Decontamination Applications

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Synthesis of size-controlled silica-supported TiO2 photocatalysts

Cited by 193 publications

References 18 publications

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Computational Fluid Dynamics (CFD) Modeling of Photochemical Reactors

Photocatalytic gold recovery from spent cyanide plating bath solutions

Sand Supported Mixed‐Phase TiO2 Photocatalysts for Water Decontamination Applications

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Product

Resources

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Sand Supported Mixed‐Phase TiO₂ Photocatalysts for Water Decontamination Applications