Electrocoalescence Behavior of Droplets Dispersed with Na 2 CO 3 in Oil under the Electromagnetic Synergy Field.

Electromagnetic synergy is a more effective physical method than a single AC electric field (ACEF) to enhance oil-water separation. However, the electrocoalescence behavior of droplets dispersed with salt ions in oil under the synergistic electromagnetic field (EMSF) still lacks research. Herein, the evolution coefficient of liquid bridge diameter ( C 1 ) characterizes the growth rate of the liquid bridge diameter, a series of Na 2 CO 3 -dispersed droplets with different ionic strengths were prepared, and C 1 values of droplets under ACEF and EMSF were compared. Micro high-speed experiments revealed that C 1 under ACEF is larger than C 1 under EMSF. In particular, when σ = 100 μS·cm -1 and E = 629.73 kV·m -1 , C 1 under the ACEF is 15% larger than C 1 under EMSF. Additionally, the theory of ion enrichment is put forward, which explains the influence of salt ions on ζ potential and total surface potential in EMSF. This study provides guidance for designing high-performance devices by introducing electromagnetic synergy in water-in-oil emulsion treatment.