Multistage extraction platform for highly efficient and fully continuous purification of nanoparticles

Abstract

This paper presents a fully-continuous novel liquid-liquid-extraction (LLE) platform for the purification of nanoparticles. The use of multistage operation enhances the purity of the final stream without the expense of high solvent consumption. Two case studies, purification of CdSe quantum dots in organic solvent and that of gold nanoparticles in water, demonstrate that the LLE platform is versatile, non-destructive, and highly efficient.

Manipulation and Control of Structure and Size of Inorganic Nanomaterials in Microchemical Systems

“…(D) Photograph and scheme of a microfluidic platform with five‐stage countercurrent extraction. Reprinted with permission from . Copyright 2017, Royal Society of Chemistry.…”

“…For example, Shen et al developed a continuous liquid‐liquid extraction (LLE) microchemical system to simultaneously purify nanoparticles during preparation, as illustrated in Fig. D . The purification efficiency of the LLE strategy was much higher than that of the strategies with external fields or semi‐continuous operation.…”

In‐Situ Microfluidic Study of Biphasic Nanocrystal Ligand‐Exchange Reactions Using an Oscillatory Flow Reactor

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Oscillatory flowr eactors provide as urface energydriven approach for automatically screening reaction conditions and studying reaction mechanisms of biphasic nanocrystal ligand-exchange reactions.Sulfide and cysteine ligandexchange reactions with as-synthesized CdSe quantum dots (QDs) are chosen as two model reactions.D ifferent reaction variables including the new-ligand-to-QD ratio,the size of the particles,and the original ligand type are examined systematically.Based on the in situ-obtained UV/Vis absorption spectra during the reaction, we propose two different exchange pathways for the sulfide exchange reaction.

Quantum dots (QDs) have attracted significant attention as emerging materials for applications spanning from sensing and imaging to solar energy production. [6,7] Recently,i na ddition to nanomanufacturing,m icroscale flow chemistry has been used as am aterial and labor-efficient screening approach to study the growth mechanism of colloidal nanocrystals. [6,7] Recently,i na ddition to nanomanufacturing,m icroscale flow chemistry has been used as am aterial and labor-efficient screening approach to study the growth mechanism of colloidal nanocrystals.

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“…[8][9][10][11][12] Synthesis of QDs,both in batch and flow,frequently requires surface-passivating long-chain hydrocarbon ligands to maintain the colloidal stabilities of the particles at high temperatures.H owever,f or most QD applications,p ost-synthetic surface modification is essential to either provide QD water solubility or improve the QD charge-transfer efficiency. [6,7] Recently,e xtensive research has been carried out focusing on understanding the mechanism and kinetics of homoge-neous QD ligand-binding/-exchange reactions through avariety of spectroscopy techniques. [6,7] Recently,e xtensive research has been carried out focusing on understanding the mechanism and kinetics of homoge-neous QD ligand-binding/-exchange reactions through avariety of spectroscopy techniques.…”

“…Thei nitial long chain hydrocarbon surfactants on the QD surface act as an insulating medium around the QDs. [6,8] Thes ynthesized CdSe QDs are then purified by gel permeation chromatography (GPC). [21,22] However,t he mechanism and kinetics of this reaction are yet to be explored.…”