Acoustic Cavitation and Ionic Liquid Combined: A Modeling Investigation of the Possible Promises in Terms of Physico-Chemical Effects

Abstract

The present work is based on a mathematical model describing a single acoustic cavitation bubble oscillating under an ultrasonic field of 200 and 300 kHz and an acoustic amplitude of 1.8 atm within 1-butyl-3-methylimidazolium acetate. The model integrates the dynamics of bubble oscillation, the thermodynamics applied to the interior of the bubble and at its interface, and the sonophysical and sonochemical events occurring in the presence of dissolved cellulose in the ionic liquid. The performed simulations shed light on the major physical effects of acoustic cavitation, namely the shockwave and microjet, as well as the sonochemical effects in terms of the degradation rate of the dissolved cellulose in the secondary reactional site, i.e., the interface. The predominance of the effects and its dependency of the acoustic frequency is tackled from an energetic point of view. It is demonstrated that 300 kHz offers the lowest heat flow across the bubble interface, lowering the chances for the sonochemical degradation of cellulose, while 200 kHz offers a significant degradation rate, attaining 71.4 mol·dm−3·s−1, as well as harsher microjets and shockwaves with powers of 3300 and 900 mW at collapse, respectively.

Keywords

• ultrasounds
• acoustic cavitation
• [C4mim][CH3COO]
• cellulose
• temperature
• pressure