High Pressure for Dispersing and Deagglomerating Nanoparticles in Aqueous Solutions

Sauter, Christian; Schuchmann, Heike P.

doi:10.1002/ceat.200700115

Cited by 38 publications

(13 citation statements)

References 12 publications

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“…intensity and, thus, to the dispersion efficiency. This is according to Sauter and Schuchmann [12] who stated that small areas of high energy dissipation are required to achieve an efficient dispersion. As shown in Eq.…”

Section: Influence Of the Channel Heightmentioning

confidence: 92%

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Effect of Microchannel Geometry on High‐Pressure Dispersion and Emulsification

et al. 2011

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Experimental investigations of the effect of microchannel geometry on high-pressure dispersion and emulsification were carried out. Customized microchannels of varying geometric principles were fabricated in silicon and steel. In order to characterize the process efficiency of microchannel geometries, the effects of the process parameters (mean velocity, Reynolds number, and local pressure drop) were examined and correlated to the dispersion and emulsification results. It is demonstrated that high pressure losses focused at a small channel length and high velocity gradients lead to high stress intensities and, in consequence, to low particle or droplet sizes. Thus, 2D orifices were successfully further improved regarding their process efficiency by adding a third-dimension constriction.

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Section: Influence Of the Channel Heightmentioning

confidence: 92%

“…This leads to the assumption that different mechanisms are responsible for the dispersion at the different geometry types. Additionally, cavitation stresses have not been taken into account in the analyses but are suspected to contribute to dispersion in microchannels [12,15,16].…”

Section: Influence Of the Channel Heightmentioning

confidence: 99%

Effect of Microchannel Geometry on High‐Pressure Dispersion and Emulsification

et al. 2011

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“…Other process devices used by previous researchers include the sawtooth impeller (Xie et al, 2007), batch rotor-stator (Xie et al, 2007;Pacek et al, 2007), high pressure devices Sauter and Schuchmann, 2012), stirred bead mills (Kowalski et al, 2008, Schilde et al, 2011 and ultrasonicators (Sauter et al, 2006(Sauter et al, , 2008. Some of the studies included numerical modelling to develop both an understanding of the flows within process devices which are not accessible for measurements and also models describing the deagglomeration process (Baldyga et al, 2006(Baldyga et al, , 2007(Baldyga et al, , 2008(Baldyga et al, , 2009.…”

Section: Introductionmentioning

confidence: 99%

Comparative performance of in-line rotor-stators for deagglomeration processes

Özcan-Taşkın

Padron

Kubicki

2016

Chemical Engineering Science

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In-line rotor-stators are used for a wide range of power intensive dispersion applications, including the breakup of immiscible liquid droplets or agglomerates. This study, performed within the DOMINO project at BHR Group, aimed at studying the performance of three different rotor-stator head designs for deagglomeration processes. A given test system, nanoscale silica particles-in-water, was used to identify the mechanism and kinetics of break-up and determine the smallest attainable size. Three rotorstator head designs used were the GPDH-SQHS and EMSC screens from Silverson and Ytron Z-Lab from Ytron. These in-line rotor-stators were used in the recirculation loop of a stirred tank with a total dispersion volume of 100 litres. Power input and residence time were varied by changing the rotor speed and dispersion flow rate. Breakup was found to occur through erosion regardless of the operating conditions or rotor-stator design. The smallest fragments obtained were aggregates, rather than primary particles, and these were of a mean diameter of 150-200 nm; also independent of the operating conditions or rotor-stator head design. With a given rotor-stator operated at a given flow rate, increasing the rotor speed and hence the power input increased the break up kinetics. For a given design at a given specific power input, whilst the break up rate per tank turnover decreased when the flow rate was increased, the total processing time could be reduced. There were differences in the volume of the mixer head and chamber volumes; in addition, a smaller flow rate range could be covered with the Ytron design. Comparison of the different designs was therefore not straightforward. It could however be shown that the rotor-stator designs with a high number and small size of holes and/or gaps have a faster break up rate.

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“…Different process devices used for the purpose include the stirred bead mill (Stenger et al, 2005;Kowalski et al, 2008;Schilde et al, 2010), ultrasonic dispersers (Baldyga et al, 2008b(Baldyga et al, , 2009Quarch et al, 2010) in-line rotor-stators (Baldyga et al, 2008a;Padron et al, 2008;Özcan-Taşkın et al, 2016), a batch rotor-stator or high pressure devices (Sauter and Schuchmann, 2007;Seekkuarachchi et al, 2008 andXie et al, 2008). Local energy dissipation rate in these devices, responsible for the breakup of agglomerates, can be orders of magnitude higher than the average energy dissipation rate.…”

Section: Introductionmentioning

confidence: 99%

Dispersion of clusters of nanoscale silica particles using batch rotor-stators

Kamaly

Tarleton

Özcan-Taşkın

2017

Advanced Powder Technology

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Nanoparticle powders added into a liquid medium form structures which are much larger than the primary particle size (aggregates and agglomerates)-typically of the order of 10's of microns. An important process step is therefore the deagglomeration of these clusters to achieve as fine a dispersion as possible. This paper reports the findings of a study on the dispersion of hydrophilic fumed silica nanoparticle clusters, Aerosil 200V, in water using two batch rotor-stators: MICCRA D-9 and VMI. The MICCRA D-9 head consists of a set of teeth for the stator and another for the rotor, whereas the VMI has a stator with slots and a rotor which consists of a 4-bladed impeller attached to an outer set of teeth. The dispersion process, studied at different power input values and over a range of concentrations (1, 5, 10 wt.%), was monitored through the evolution of PSD. Erosion was found to be the dominant breakage mechanism irrespective of operating conditions or rotor-stator type. The smallest attainable size was also found to be independent of the power input or the design of the rotor-stator. Break up kinetics increased upon the increase of power input, and this also depended on the rotor-stator design. With MICCRA D-9 which has smaller openings on both the stator and rotor, the break up rate was faster. Increasing the particle concentration decreased break up kinetics. It could also be shown that operating at high concentrations can still be beneficial as the break up rate is higher when assessed on the basis of specific power input per mass of solids.

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High Pressure for Dispersing and Deagglomerating Nanoparticles in Aqueous Solutions

Cited by 38 publications

References 12 publications

Effect of Microchannel Geometry on High‐Pressure Dispersion and Emulsification

Effect of Microchannel Geometry on High‐Pressure Dispersion and Emulsification

Comparative performance of in-line rotor-stators for deagglomeration processes

Dispersion of clusters of nanoscale silica particles using batch rotor-stators

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