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Contactless mass transfer for intra-droplet extraction.
Shusaku Asano1,2, Yu Takahashi3, Taisuke Maki3
1Institute for Materials Chemistry and Engineering, Kyushu University, 6-1, Kasuga Koen, Kasuga, 816-8580, Japan. shusaku_asano@cm.kyushu-u.ac.jp.
Scientific Reports
|May 8, 2020
Summary
This study shows contactless mass transfer between aqueous droplets in microfluidic channels using Taylor flow. Optimized conditions achieved 93% transfer of bromothymol blue (BTB) within minutes.
Area of Science:
- Microfluidics
- Mass Transfer
- Chemical Engineering
Background:
- Taylor flow in microchannels enables droplet-based operations.
- Contactless mass transfer is crucial for efficient chemical processing.
- Controlling droplet interactions is key for separation and concentration.
Purpose of the Study:
- To demonstrate contactless mass transfer between aqueous slugs in oil-based Taylor flow.
- To investigate factors influencing mass transfer efficiency, such as channel geometry and interfacial tension.
- To achieve high transfer rates and explore potential for solute concentration.
Main Methods:
- Utilized milli-channels with Taylor flow of alternating aqueous and oil slugs.
- Employed solenoid valves and optical sensors for droplet separation.
- Demonstrated mass transfer using bromothymol blue (BTB) as a model solute.
- Investigated the effect of channel meandering on droplet velocity and mass transfer.
Main Results:
- Achieved contactless mass transfer of BTB between aqueous slugs.
- Observed slug merging due to velocity differences influenced by interfacial tension.
- Identified position-specific mass transfer activity at the rear of aqueous slugs.
- Demonstrated that meandering channels enhance mass transfer efficiency.
- Reached nearly complete (93%) BTB transfer in a few minutes under optimized conditions.
Conclusions:
- Contactless mass transfer in Taylor flow is feasible and efficient.
- The system allows for solute concentration by manipulating slug lengths.
- This microfluidic approach minimizes oil phase usage for advanced separation processes.
