Mass transfer intensification for carbon quantum dot nanofluid drops under pulsed electric fields

Area of Science:

• Chemical Engineering
• Materials Science

Background:

• Liquid-liquid extraction is crucial in chemical processes.
• Mass transfer limitations can reduce extraction efficiency.
• Carbon quantum dots (CQDs) show potential for enhancing transport phenomena.

Purpose of the Study:

• To investigate the synergistic effect of CQD nanofluids and pulsed electric fields on mass transfer intensification.
• To optimize parameters like CQD concentration and electric field conditions.
• To model the enhanced mass transfer process.

Main Methods:

• Synthesis and characterization of CQD and CQD-Fe nanofluids.
• Experimental liquid-liquid extraction using kerosene-acetic acid-water system.
• Application of pulsed electric fields with varying frequencies and strengths.
• Hydrodynamic analysis and mass transfer coefficient measurement.
• Modeling using adapted Kumar and Hartland equation.

Main Results:

• CQD and CQD-Fe nanofluids were synthesized with sizes of 7.2 and 13.4 nm.
• Mass transfer enhancement reached up to 263.5% with CQDs and 291.6% with CQD-Fe.
• Optimal conditions were identified for CQD concentration and electric field parameters.
• Drop hydrodynamics followed the Grace model.
• An adapted model successfully reproduced the mass transfer coefficient data.

Conclusions:

• The combination of CQD nanofluids and pulsed electric fields offers significant mass transfer intensification in liquid-liquid extraction.
• Electro-induced motion of CQDs is the primary mechanism for enhancement.
• The developed model provides a satisfactory prediction of the mass transfer coefficient.