Breakage of TiO2 agglomerates in electrostatically stabilized aqueous dispersions

Mandzy, Natalia; Grulke, Eric A.; Druffel, Thad

doi:10.1016/j.powtec.2005.08.020

Cited by 378 publications

(225 citation statements)

References 15 publications

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“…As it can be seen, the primary particles present sizes in nanometer range. These particles agglomerate forming aggregates with different shapes and morphologies, which influence the surface roughness, haze and transparency of the bulk material [26]. The approximate size of the P25 nanoparticles is between 15 and 30 nm, which is in accordance with values presented in literature [27].…”

Section: Photocatalysts Characterizationsupporting

confidence: 87%

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Synthesis and assessment of a graphene-based composite photocatalyst

Magalhães

Ângelo

Sousa

et al. 2015

Biochemical Engineering Journal

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A novel composite photocatalyst prepared from graphene and commercial TiO2 (P25 from Evonik) was synthesized, exhibiting enhanced photocatalytic activity for methylene blue degradation, when com-pared with pristine P25. Additionally, the new catalyst showed 20% more NO conversion under UV light than P25. The band gap of the catalyst, obtained from diffuse reflectance, was 2.95 eV indicating an extended light absorption up to 420 nm. The novel photocatalyst was further tested for inactivating microorganisms showing better results than the reference photocatalyst. Under visible light, the viability loss of the reference bacterial strain Escherichia coli DSM 1103 was two times higher than with the bare P25; it was observed 29% of inactivation with the P25/graphene composite and 14% with the P25 sample, following standard ISO 27447:2009.

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Section: Photocatalysts Characterizationsupporting

confidence: 87%

“…3 shows the morphology of P25 sample. The high agglomeration observed is caused by the high surface energy of the nanoparticles [26]. As it can be seen, the primary particles present sizes in nanometer range.…”

Section: Photocatalysts Characterizationmentioning

confidence: 92%

Synthesis and assessment of a graphene-based composite photocatalyst

Magalhães

Ângelo

Sousa

et al. 2015

Biochemical Engineering Journal

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“…At 1400 bar (diamonds) the small and large particle modes have shifted to about 50 and 200 nm, respectively. Mandzy et al [30] measured initial agglomerate sizes of 1 μm for Degussa P25 in aqueous (pH = 8) solutions, this was reduced to about 200 nm after ultrasonication (24 kHz) for 2 h, in agreement with the large particle mode obtained here after dispersion at 1400 bar (Fig. 7).…”

Section: Agglomerate Fragmentationsupporting

confidence: 87%

“…The zeta potential (ζ) of a suspension is a function of particle surface charge [30]. In dispersions where ζ is close to zero (isoelectric point), particles tend to agglomerate.…”

Section: Particle Dispersionmentioning

confidence: 99%

“…Similarly by ultrasonication, after a rapid initial size reduction, continued ultrasonication does not further alter the size significantly [13,32] and nanopowders cannot be broken completely down to their primary particle size [30]. This is attributed to erosion mechanism where primary particles and small aggregates consisting of a few primary particles break away from the larger agglomerates [30] as with ultrasonication of sol-gel made silica agglomerates also [9]. Also during impaction of aerosol agglomerates only bonds between clusters are broken while the subunits themselves do not fragment [7].…”

Section: Agglomerate Fragmentationmentioning

confidence: 99%

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Distinguishing between aggregates and agglomerates of flame-made TiO2 by high-pressure dispersion

et al. 2008

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The potential of high-pressure dispersion (HPD) and dynamic light scattering (DLS) is explored for rapid and quantitative estimation of the extent of particle aggregation and agglomeration by analyzing the entire particle size distribution. Commercially available and tailor-made TiO 2 particles by flame spray pyrolysis (FSP) were characterized by X-ray diffraction, nitrogen adsorption and transmission electron microscopy (TEM). Volume distributions of these titania particles were obtained by DLS of their electrostatically stabilized (with Na 4 P 2 O 7 ) aqueous suspensions. Dispersing these suspensions through a nozzle at 200 to 1400 bar reduced the size of agglomerates (particles bonded by weak physical forces) resulting in bimodal size distributions composed of their constituent primary particles and aggregates (particles bonded by strong chemical or sinter forces). Sintering FSP-made particles from 200 to 800°C for 4 h progressively increased the minimum primary particle size (by grain growth) and aggregate size (by neck growth and phase transformation).

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Chameleon Nonwovens by Green Electrospinning

Giebel¹,

Mattheis²,

Agarwal³

et al. 2013

Adv Funct Materials

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Electrospun ionic nonwovens are obtained by green electrospinning of aqueous dispersions. The resulting nonwovens are termed as chameleon nonwovens since their surface properties can be tailored in a large variety by coating of different functionalities following the protocol of the layer-bylayer process (LBL). The dimensional stability of the electrospun fi bers in the chameleon nonwovens is achieved by photo-cross-linking after electrospinning and thereby overcoming the repulsive forces of the ionic moieties in the fi bers. Depending on the nature of the ionic moieties different materials are coated by LBL including dyes, antibacterial materials, silver, and gold nanoparticles. Enhanced coating effi ciency for coating of metal nanoparticles is observed when the chameleon nonwovens were precoated by a polyelectrolyte.

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Breakage of TiO2 agglomerates in electrostatically stabilized aqueous dispersions

Cited by 378 publications

References 15 publications

Synthesis and assessment of a graphene-based composite photocatalyst

Synthesis and assessment of a graphene-based composite photocatalyst

Distinguishing between aggregates and agglomerates of flame-made TiO2 by high-pressure dispersion

Chameleon Nonwovens by Green Electrospinning

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