Abstract
Many industrial processes generate “oily wastewaters”, characterized by low volume fractions of micrometer-scale, oil-in-water droplets that are difficult to separate by mechanical or chemical means. High dc voltages are traditionally applied for the electrical demulsification of water-in-oil emulsions. In this work, we demonstrate that oil-in-NaOH contaminated wastewater emulsions respond to low-voltage, low-frequency oscillatory fields by aggregating near the electrodes. Optical microscopy shows that droplets initially separate upon the application of an ∼10 Hz oscillatory field but slowly form aggregates over longer time scales of several minutes. The rate of aggregation varies nonmonotonically with the applied field strength, exhibiting a peak near 3 Vpp and decreasing at higher strengths. Finally, we demonstrate that a combination of low-frequency fields with a small dc offset induces coalescence to break the emulsion. These results point toward a low-energy, nonchemical method for recovering oils from oily wastewaters.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
