Phase separation of parallel laminar flow for aqueous two phase systems in branched microchannel

Abstract

Aqueous two phase systems (ATPSs) have good biocompatibility and special selectivity. Their phase equilibrium and applications in biological analysis have received much attention. Herein, parallel laminar flow (PLF) in the microchannel can provide an effective platform to enhance mass transfer and preserve separate phases simultaneously. As fundamentals in feasible and convenient sampling of PLF for ATPS, the phase separation methods and rules in branched microchannel were studied in this work, selecting PEG 4000 ? Na 2 SO 4 ? H 2 O as a model system. The exploration of flow pattern showed that a stable PFL was easily to form in the shallow microchannel of 200 lm (depth) 9 600 lm (width), as long as the velocity of lower phase was higher than 0.51 mm/s. The phase interface of PLF could be easily controlled by the flow ratio of two phases. Single-phase separation could be reliably achieved in T-junction outlets when the flow rate of outlet ascertains to be smaller or larger than that of inlet on the same side. The trifurcate outlets with an extra middle channel could help realize a simultaneous two-phase separation. The flow rate of the extra channel is the key for the phase separation performance, the range of which available for simultaneous two-phase separation is determined by the resistance balance and the flow rates deviation offsetting as well. It is favor for increasing phase separation efficiency to make the products of flow rate, viscosity, and the length of corresponding outlet channel close with each other for the upper phase and the lower phase. The adjustable lengths of three channels can provide flexible choices to enhance simultaneous two-phase separation of diversified ATPSs at various operating flow ratios. A multiport microchip with T-junction inlets and trifurcate outlets designed for adjusting the lengths of branched channels on-chip is a convenient tool for PLF contact and in situ phase separation of ATPSs in varieties of application.

Modeling of kinetics of a microfluidic reaction–extraction process for the preparation of KH 2 PO 4

“…(2), with forward and backward rate constants, and , respectively, and with an equilibrium constant (13) Assume that the forward and backward reactions are both first-order in each reactant.…”

“…Among them, liquid-liquid extraction is one of the important and significant applications, such as aqueous two-phase (ATP) extraction [12,13], acid extraction [14,15], and hydrometallurgy extraction [16,17]. It is reasonable to anticipate that microfluidics can facilitate the fundamental study on the mass transfer and reaction rules in the preparation of KH 2 PO 4 using the extraction method, with unique features including continuous-flow operation, excellent mass and heat transfer performance, and precise control over process conditions.…”

Interfacial Phenomena and Fluid Control in Micro/Nanofluidics

“…The interface position (3-phase contact line in the microchannel) fluctuates easily. 91 Under a condition with a significant contact angle hysteresis and with high interfacial tension, the interface position is more likely to be pinned at a certain point. For simplicity, the liquid-liquid-solid contact line is assumed to be at the center of the channel.…”

Parallel flow of immiscible liquids in a microreactor: modeling and experimental study

“…Zhao et al (2006) recognized parallel flow for being an effective way to perform solvent extraction or purification, which is a key operation in analytical processing. Lu et al (2011) acknowledged parallel laminar flow for being an effective platform for enhanced mass transfer, for simultaneous preservation of separate phases, for fast phase equilibrium or diffusivity determination with trace chemical consumption, and for continuous, efficient and even multi-stage industrial extraction techniques. Münchow et al (2007) utilized parallel flow for electrophoretic partitioning of proteins and Guillot et al (2008) developed a method to perform automated rheological measurements on a microfluidic chip.…”