Segmented microfluidics for synthesis of BaSO4 nanoparticles

Sen, Nirvik; Koli, V.; Singh, K.K.; Panicker, Lata; Sirsam, R.; Mukhopadhyay, S.; Shenoy, K.T.

doi:10.1016/j.cep.2018.01.012

Cited by 19 publications

(7 citation statements)

References 33 publications

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“…To address this issue, the liquid–liquid segmented flow has been widely employed. For instance, Sen et al introduced dodecane to form liquid–liquid segmented flow to synthesize BaSO 4 and the microfluidic-based system was robust enough to operate continuously for a long time without any chocking . In the liquid–liquid segmented flow, a thin film of continuous phase exists between the channel wall and dispersed plugs that can effectively prevent the nanoparticles from depositing on the channel wall and in turn lower the risk of channel clogging.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, Sen et al introduced dodecane to form liquid−liquid segmented flow to synthesize BaSO 4 and the microfluidic-based system was robust enough to operate continuously for a long time without any chocking. 35 In the liquid−liquid segmented flow, a thin film of continuous phase exists between the channel wall and dispersed plugs that can effectively prevent the nanoparticles from depositing on the channel wall and in turn lower the risk of channel clogging. More importantly, the internal circulation inside the aqueous plugs can enhance the micromixing efficiency of the reactants and narrow down the residence time distribution (RTD) compared to the single-phase continuous flow.…”

Section: Resultsmentioning

confidence: 99%

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Continuous Synthesis of Reduced Graphene Oxide-Supported Bimetallic NPs in Liquid–Liquid Segmented Flow

Luo

Yang

Chen

2020

Ind. Eng. Chem. Res.

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A segmented flow-based approach was proposed for the deposition of AgPd bimetallic nanoparticles (NPs) on reduced graphene oxide (AgPd/rGO) in continuous mode. AgPd/rGO was synthesized by reducing AgNO 3 and Pd(NO 3 ) 2 simultaneously with NaBH 4 in the presence of graphene oxide (GO) and poly(vinylpyrrolidone) (PVP). The synthesis included two steps, i.e., the formation of AgPd/GO and subsequent reduction of AgPd/GO to AgPd/rGO, which were both confined in dispersed aqueous plugs generated via introducing n-octane. Benefiting from the efficient micromixing in aqueous plugs, the as-prepared AgPd/ rGO exhibited a narrower particle size distribution of AgPd NPs than that synthesized by the batch method. The segmented flowbased method was successfully extended to the preparation of PtPd/rGO and PtCu/rGO composites, demonstrating the versatility of this method. Moreover, the catalytic performance of the resultant AgPd/rGO was better than those of Ag/rGO and Pd/rGO in the catalytic reduction of p-nitrophenol to p-aminophenol because of the synergistic effect between the constituent metals.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Continuous Synthesis of Reduced Graphene Oxide-Supported Bimetallic NPs in Liquid–Liquid Segmented Flow

Luo

Yang

Chen

2020

Ind. Eng. Chem. Res.

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“…Here, we are not studying the effect of reactant molar ratio, BaCl 2 /Na 2 SO 4 , which has been found to affect the particle size in previous studies carried out by different groups. Excess of one ion (barium or sulfate) in the solution further helps in reducing the particle size of the precipitate. , The authors in these studies have hypothesized that excess of the ions leads to charge build-up on the surface of the particle which prevents aggregation of particles due to electrostatic stabilization. Table contains the different initial reactant concentrations used in a different set of experiments.…”

Section: Methodsmentioning

confidence: 99%

“…Excess of one ion (barium or sulfate) in the solution further helps in reducing the particle size of the precipitate. 22,24 The authors in these studies have hypothesized that excess of the ions leads to charge build-up on the surface of the particle which prevents aggregation of particles due to electrostatic stabilization. For a constant length reactor, a change in the flow rate also leads to a change in the residence time.…”

Section: ■ Backgroundmentioning

confidence: 99%

“…The particle size was observed to decrease when the flow rate of the reactants or the inert gas was increased. Sen et al 22 investigated the effect of flow rate in a slug flow on the size of particles and observed that mean particle size initially increases up to a critical velocity and starts decreasing beyond the critical value. The polydispersity index (PDI) also follows the same trend.…”

Section: ■ Introductionmentioning

confidence: 99%

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Tuning of Particle Size in a Helical Coil Reactor

Pal

Dhasmana

Nigam

et al. 2019

Ind. Eng. Chem. Res.

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This study investigates the effect of initial reactant concentration, residence time, and flow on the particle size and particle size distribution produced by single-phase reactive precipitation between BaCl2 and Na2SO4 in a helical coil reactor. Helical coils offer enhanced mixing due to the secondary flow generated by the imbalance of centrifugal forces. The particles produced in a helical coil reactor are found to have smaller sizes and narrower size distribution compared to a straight tube reactor under similar process conditions. It is shown that the average particle size in a helical coil reactor decreases with increasing Dean number, and particle size distribution becomes narrower at higher Dean number. For a reactant concentration of 0.5 M with the reactant concentration ratio of one, the average size changed from 580 to 263 nm when Dean number changed from 64 to 370. The initial reactant concentration is defined in terms of supersaturation ratio, and a decreasing trend in size is also observed with increasing supersaturation ratio. The particle size distribution curve also became narrower at higher supersaturation ratio. The residence time is observed to have no visible effects on the particle mean size and particle size distribution for the range of residence time, from 6 to 34 s, studied for the helical coil in this work.

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A high‐throughput chaotic advection microreactor for preparation of uniform and aggregated barium sulfate nanoparticles

et al. 2022

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A high-throughput (105.5 g/h) passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare aggregated Barium sulfate (BaSO 4 ) particles of high primary nanoparticle size uniformity. Threedimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux-Dushman experiments indicate that almost complete mixing down to molecular level can be achieved and the prepared BaSO 4 nanoparticles were with narrow primary particle size distribution (PSD) having geometric standard deviation, σ g , less than 1.43 when the total volumetric flow rate Q total was larger than 10 ml/min. By selecting Q total and reactant concentrations, average primary particle size can be controlled from 23 to 109 nm as determined by microscopy. An average size of 26 nm with narrow primary PSD (σ g = 1.22) could be achieved at Q total of 160 ml/min.

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Segmented microfluidics for synthesis of BaSO4 nanoparticles

Cited by 19 publications

References 33 publications

Continuous Synthesis of Reduced Graphene Oxide-Supported Bimetallic NPs in Liquid–Liquid Segmented Flow

Continuous Synthesis of Reduced Graphene Oxide-Supported Bimetallic NPs in Liquid–Liquid Segmented Flow

Tuning of Particle Size in a Helical Coil Reactor

A high‐throughput chaotic advection microreactor for preparation of uniform and aggregated barium sulfate nanoparticles

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