Optimisation of Interfacial Modification by Two-Stage Microwave Irradiation

Microwave-assisted de-emulsification is attractive in the processes of petroleum production and refining. The main advantage of microwaves is their direct influence on the surfactant layer at the oil/water interface. Previously, an effective interfacial modification was demonstrated by pulsed microwave irradiation. However, the effect of the modification diminished during the off interval of the pulse irradiation. In this study, two-stage microwave irradiation with different powers and durations was applied as a method to maintain an interfacial effect. The power of the second stage was changed to optimise the modification. Quick modification was obtained by high-power irradiation followed by low-power irradiation. It was confirmed a sustained modification was maintained by a moderate power of the second irradiation. This observation indicates a re-adsorption or re-structure process after the first irradiation is suppressed by the second irradiation. The results open new opportunities to optimise microwave operation in oil/water systems.