Liquid–liquid phase transfer of magnetite nanoparticles — Evaluation of surfactants

Erler, Jacqueline; Machunsky, Stefanie; Grimm, P.; Schmid, Hans‐Joachim; Peuker, Urs A.

doi:10.1016/j.powtec.2012.09.047

Cited by 25 publications

(12 citation statements)

References 20 publications

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“…With this technique, where inorganic materials react at the water–nonpolar solvent interface, nanoparticles , and nanoparticle dispersions can be prepared through phase transfer . Moreover, through the use of the liquid–liquid biphasic systems, surface modification of TiO 2 ,, and Fe 3 O 4 , nanoparticles could be achieved. In the conventional method for modifying the surface of nanoparticles and nanosheets using organic solvents, modified nanoparticles and nanosheets are obtained as colloidal dispersions of organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent in a Biphasic System

et al. 2019

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Oleyl phosphate-modified HLaNb2O7·xH2O nanosheets (OP_HLaNb nanosheets) were prepared via phase transfer from an aqueous phase, comprising a dispersion of HLaNb2O7·xH2O (HLaNb) nanosheets, formed through the intercalation of tetrabutylammonium ion (TBA+) in the interlayer space of HLaNb and subsequent delamination, to a cyclohexane phase containing oleyl phosphate (OP, a mixture of monoester and diester). The modification of HLaNb nanosheets with OP was essentially completed within 3 days at a pH value of 2 or 4. Both infrared and solid-state 13C cross-polarization and magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of the OP_HLaNb nanosheets showed the presence of OP and/or related species and TBA+ on the HLaNb nanosheet surface. The solid-state 31P MAS NMR spectra of OP_HLaNb nanosheets exhibited new signals at −2 and 0 ppm, the former of which indicates the formation of Nb–O–P bonds. These whole data set obtained by complementary techniques clearly point out the modification of the HLaNb nanosheet surface by OP moieties causing a phase transfer. OP_HLaNb nanosheets showed higher dispersibility in cyclohexane than the OP_HLaNb_interlayer nanosheets, which were prepared via stepwise substitution reactions in the interlayers of HLaNb to achieve surface modification with OP and subsequent exfoliation in cyclohexane. The presence of TBA+ on the HLaNb nanosheets and the use of a liquid–liquid biphasic system were likely to improve the dispersibility. These results show that the preparation of OP-modified HLaNb nanosheets which could be well-dispersed in the cyclohexane phase was successful because of the use of a liquid–liquid biphasic system.

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Section: Introductionmentioning

confidence: 99%

Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent in a Biphasic System

et al. 2019

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“…At first, the nanoparticles agglomerate partly due to the instable conditions in the aqueous phase as already mentioned in [19]. In the drop column, after injecting the organic phase, no sedimentation takes place due to the stirring effect of the rising liquid drops.…”

Section: Introductionmentioning

confidence: 90%

Application of a Particle Extraction Process at the Interface of Two Liquids in a Drop Column—Consideration of the Process Behavior and Kinetic Approach

Erler¹,

Leistner²,

Peuker³

2014

ACES

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The focus of this research is a new type of particle extraction process for the transfer of magnetite nanoparticles from an aqueous to an immiscible organic phase, directly through the liquid-liquid phase boundary in a drop column. The particle extraction process comprises several advantages such as a minimum amount of stabilizing surfactant, no exposure of the particles to a gas atmosphere and with it the avoidance of sintering by capillary forces and a high particle concentration in the receiving phase as well. The study presents experimental results of the characterization of the process environment and the transfer behavior in a drop column. The solution of surfactant in the continuous phase has been investigated during a particle-free phase transfer experiment including the measurements of the total organic carbon (TOC) content and analysis of the size of the stabilized droplets using the laser diffraction spectroscopy. The determination of the transfer fluxes, the mass flows as well as the yield of transferred magnetite by ICP-OES measurements provide information on the impact of interaction of the elementary processes at the phase boundary. Furthermore, the transfer kinetics of the process is described and compared with calculated theoretical values resulting from a kinetic approach.

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“…The microballoon synthesis is based on a concept that simultaneously combines the surface modification of nanoparticles by a coupling agent like MEMO − with phase transfer from an aqueous phase to an organic phase as already known for surfactant-assisted paths. − Typically, 210 mL of the acidic aqueous nanoparticle dispersion was carefully covered with 200 mL of oil such as cyclohexane. Then 1240 μL (5.2 mmol) of MEMO was slowly dropped into the oil phase.…”

Section: Methodsmentioning

confidence: 99%

Hollow Superparamagnetic Microballoons from Lifelike, Self-Directed Pickering Emulsions Based on Patchy Nanoparticles

et al. 2016

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Herein, the formation of hollow microballoons derived from superparamagnetic iron oxide nanoparticles with silica patches is reported. Depending on the experimental conditions, single- or multishelled superparamagnetic microballoons as well as multivesicular structures were obtained. We show how such structural changes follow a lifelike process that is based on self-directing Pickering emulsions. We further demonstrate that the key toward the formation of such complex architectures is the patchy nature of the nanoparticles. Interestingly, no well-defined ordering of patches on the particles surface is required, unlike what theorists formerly predicted. The resultant hollow microballoons may be turned into hollow carbonaceous magnetic microspheres by simple pyrolysis. This opens the way to additional potential applications for such ultralightweight (density: 0.16 g·cm) materials.

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Liquid–liquid phase transfer of magnetite nanoparticles — Evaluation of surfactants

Cited by 25 publications

References 20 publications

Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent in a Biphasic System

Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent in a Biphasic System

Application of a Particle Extraction Process at the Interface of Two Liquids in a Drop Column—Consideration of the Process Behavior and Kinetic Approach

Hollow Superparamagnetic Microballoons from Lifelike, Self-Directed Pickering Emulsions Based on Patchy Nanoparticles

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