Abstract
In this study, a model of CCl4 sono-pyrolysis inside an acoustic bubble is used to provide a novel mechanistic and kinetics study of CCl4 conversion. The impact of fluid temperature (10–50 °C) on CCl4 conversion and the resulted products is illustrated for various aqueous CCl4 concentrations and acoustic intensities (0.7–1.5 W/cm2). With a concentration less than 3 × 10−3 M, 1 W/cm2 is sufficient for the complete degradation of CCl4 at 20 °C. However, at 10 °C, 1.5 W/cm2 is much than enough to degrade CCl4 completely, regardless of its concentration in solution. The generation of reactive chlorine species (RCS) increased proportionately with the temperature rise when the intensity was 0.7 W/cm2. In contrast, between 1 and 1.5 W/cm2, increasing the liquid temperature from 10° to 40 °C has a beneficial effect on the sonolytic activity of the cavity. However, this positive impact continues to be observed only for·OH radicals when the bulk liquid temperature is greater than 40 °C (the yield of RCS, H·, HCl, and HOCl is amortized). According to the simulation results, it was concluded that the rapid sono-degradation of nonvolatile pollutants in the presence of CCl4 was mainly due to the RCS and·OH radicals generated at the efficient bubble collapse.
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•The chemical bubble yield increases with the increase of [CCl4] and liquid temperature.•CCl4 pyrolysis enhanced the formation reactive chlorine species (RCS) and·OH radicals.•For 1 W/cm2, a liquid temperature of 20 °C is sufficient for a complete degradation of CCl4.•For 1.5 W/cm2, a liquid temperature of 10 °C is sufficient for a total degradation of CCl4.•The yield of reactive chlorine species and·OH depends on acoustic intensity and temperature.