Magnetic actuation of catalytic microparticles for the enhancement of mass transfer rate in a flow reactor

Abstract

Permanent WRAP URL:http://wrap.warwick.ac.uk/81857 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. AbstractThe effect of periodic changes in particle velocity on mass transfer to the reacting surface of a magnetic particle with a diameter 225 m in laminar flow has been investigated in a microfluidic reactor. The periodic particle motion in a fluid was investigated under a sinusoidal magnetic field generated by a quadrupole arrangement of electromagnets around the reactor. The effect of operating frequency of the rotating magnetic field, intensity of the magnetic field, and phase shift between the two sets of magnets on particle dynamics has been studied. Three particle motion modes have been observed depending on the frequency of the applied field. The mass transfer rate was estimated under steady velocity and variable velocity of the particle using a mass transfer correlation by Feng and Michaelides (Int. J. Heat Mass Transfer 44 (2001) 4445). The validity of this correlation for the case of variable particle velocity has been confirmed with a 2D numerical model, describing actual hydrodynamics and mass transfer towards the particle surface. The mass transfer coefficient *Revised Manuscript (clean for typesetting) Click here to view linked References 2 depends both on the mean particle velocity and the deviation of velocity from the mean value.The periodic movement with variable particle velocity reduces the mass transfer coefficient by 7.6% as compared to steady state motion with the same mean velocity.

Continuous Solid Particle Flow in Microreactors for Efficient Chemical Conversion

“…The liquid–solid mass transfer is also affected by periodical changes in the particle velocity induced by the applied magnetic field. According to the simulation in the case of a fast chemical reaction on the surface of catalytic magnetic microparticles placed in laminar flow microreactors, the liquid–solid mass transfer coefficient could be reduced up to 7.6% by the periodic particle movement with different particle velocities, when compared with that under steady state motion with the same mean velocity . Thus, a further optimization of magnetic actuation is necessary to maximize the mass transfer rate.…”

Direct Probing of Fe3O4 Nanoparticle Surface Temperatures during Magnetic Heating: Implications for Induction Catalysis

“…10 These technologies represent remarkable advances in nanotechnology and energy efficiency, which benefit from fast heating and cooling, local heating without increasing the temperature of the surroundings substantially, 11 and process safety. 12 However, to optimize heating processes with magnetic NPs via induction heating, a more detailed understanding of heat propagation at the nanoscale and an accurate determination of the NP surface temperature are still needed. Current studies face experimental limitations regarding spatial and temporal resolution, 13 and theoretical models are still unable to predict temperatures accurately given the complexity of heat dissipation at the nanoscale.…”

“…In situ heating with magnetic nanoparticles (NP) is now ubiquitous in applications such as induction heating catalysis, − thermoactivated drug delivery, , magnetic fluid hyperthermia, , and water treatment . These technologies represent remarkable advances in nanotechnology and energy efficiency, which benefit from fast heating and cooling, local heating without increasing the temperature of the surroundings substantially, and process safety . However, to optimize heating processes with magnetic NPs via induction heating, a more detailed understanding of heat propagation at the nanoscale and an accurate determination of the NP surface temperature are still needed.…”

Synthesis of a highly active amino‐functionalized Fe3O4@SiO2/APTS/Ru magnetic nanocomposite catalyst for hydrogenation reactions

“…More recently, magnetic core–shell nanocomposites have been widely used as supports for metal nanoparticles . Composites with magnetic cores and functional shell structures have received particular attention because the magnetic cores allow the composites to be conveniently collected or separated using an external magnet . Functional shells, such as SiO 2 and C, can be applied to immobilize metal nanoparticles .…”