Hydrodynamics and Mass Transfer in a Countercurrent Multistage Microextraction System

Experimental liquid–liquid equilibrium (LLE) data are indispensable for many applications ranging from extraction column design to water partitioning of organics in the environment. However, conventional LLE experiments are time-consuming and need large sample volumes. Therefore, a measurement setup is presented for the time and material efficient determination of LLE data. The measurement setup combines the advantages of microfluidics and Raman microspectroscopy: The small dimensions of the used H-cell microchannel lead to rapid equilibration and small sample consumption; Raman microspectroscopy allows for rapid in situ quantification of all components. The measurement setup has successfully been validated by measuring the LLE of the ternary system cyclohexane–methanol–toluene. Excellent agreement with the literature data has been achieved. Thus, the developed setup allows for the efficient determination of liquid–liquid equilibria in multicomponent mixtures.

Section: Introductionmentioning

confidence: 99%

Efficient Determination of Liquid–Liquid Equilibria Using Microfluidics and Raman Microspectroscopy

Thien

Peters

Brands

et al. 2017

“…Therefore, to date, only a few studies have examined countercurrent microfluidic extraction and extractors. 52,[148][149][150][151][152][153][154][155][156][157]159,160 These studies can be classified as those related to multistage countercurrent MEs, those related to continuous countercurrent MEs, and those related to hybrid countercurrent MEs, on the basis of the mass transfer mode and details of the flow arrangement.…”

Section: Countercurrent Microfluidic Extractormentioning

confidence: 99%

“…This is easy on the macroscale, but difficult on the microscale, as the viscous force and surface tension force are dominant over the inertial force and gravity on the microscale. Therefore, to date, only a few studies have examined countercurrent microfluidic extraction and extractors. ,− ,, These studies can be classified as those related to multistage countercurrent MEs, those related to continuous countercurrent MEs, and those related to hybrid countercurrent MEs, on the basis of the mass transfer mode and details of the flow arrangement.…”

Section: Countercurrent Microfluidic Extractormentioning

confidence: 99%

Review of Microfluidic Liquid–Liquid Extractors

Xie

2017

During the last few decades, microfluidic liquid–liquid extractors have been developed to address the need for separating solutes in analytical chemistry and efficiently recovering products in microfluidic reactors. This review classifies the various microfluidic liquid–liquid extractors into three major groups based on their flow arrangement: stop-flow microfluidic extractors (MEs), cocurrent MEs, and countercurrent MEs. Each group is further classified into several subcategories based on flow pattern and/or working principle. The review focuses on how to establish these three groups of microfluidic liquid–liquid extractors, including the difficulties and corresponding solutions for establishing these MEs, as well as their advantages and disadvantages. The review ends with conclusions and the outlook of the field.

“…Following the contacting flow in each extraction stage is a phase separator. Most current laboratory-scale MCCE exploits the combined effects of surface and gravity forces, , but these designs require precise pumping between stages to maintain proper pressure balance. Our laboratory has developed a separation device that integrates a thin porous fluoropolymer membrane that is selectively wet by nonaqueous liquids. , For successful operation, a pressure drop across the membrane (Δ P mem = P out ret – P out per ) must be maintained between a capillary pressure ( P cap ) and a permeation pressure ( P per ).…”

Section: Introductionmentioning

confidence: 99%

“…26,32 Following the contacting flow in each extraction stage is a phase separator. Most current laboratory-scale MCCE exploits the combined effects of surface and gravity forces, 32,34 but these designs require precise pumping between stages to maintain proper pressure balance. Our laboratory has developed a separation device that integrates a thin porous fluoropolymer membrane that is selectively wet by nonaqueous liquids.…”

Section: Introductionmentioning

confidence: 99%

Design of Multistage Counter-Current Liquid–Liquid Extraction for Small-Scale Applications

Weeranoppanant

Adamo

Saparbaiuly

et al. 2017

Multistage counter-current liquid–liquid extraction (MCCE) is a common unit operation in the chemical industry, but the technique is often difficult to use at laboratory and small production scales, because most MCCE systems are gravity-driven and require a large volume (∼100 mL). We present a new MCCE design that integrates segmented flow mixing and membrane-based phase separators to achieve equilibrium extraction at each stage. Multichannel peristaltic pumps transfer fluids from stage to stage in a counter-current manner, rather than dedicated pumps at each stage. A self-tuning pressure control element incorporated into each separator allows robust operation, even in the presence of variation between stages and imprecise pumping. Experimental data from two classical ternary case studies (toluene–acetone–water and ethyl acetate–acetic acid–water) compare well to ASPEN Plus simulations, showing that the extraction efficiency is ∼100%, regardless of the number of stages. Finally, we demonstrate the efficiency of the small-scale MCCE system (∼2 mL/stage) with an industrial example of recovery of THF and ethyl acetate from methanol, ethanol, iso-butanol, and tert-butanol mixtures.