Kinetic and Mass Transfer of Peroxone Oxidation of Toluene Using Ultra Sonic Spray: Ab Initio Quantum Calculations and Numerical Modeling
Date
2020-01-16
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Abstract
The application of ozone along with hydrogen peroxide, commonly referred to as peroxone oxidation, is a widely investigated advanced oxidation technique to treat waste gas or wastewater. Degradation of ozone in water is a key step in the pollutant degradation mechanism, particularly in peroxone oxidation. However, the degradation of ozone in water is not well understood. In the research documented here, peroxone treatment is studied in detail via reaction and transport phenomena modeling, as well as computational chemistry simulation. Ab initio studies, using the coupled cluster calculations method, were conducted to investigate the kinetics of ozone degradation in gas and aqueous phases considering the ozone-hydroperoxyl radical reaction and the dissociation equilibrium of the hydroperoxyl radical. The predictions of the ozone degradation rate at low pH (<6) is improved by up to two orders of magnitude over existing models. For peroxone oxidation of toluene, the results from the research reveal that dissolution of ozone in water is the rate determining step in the pollutant degradation mechanism. However, the major issue that limits widespread application of peroxone oxidation for waste gas treatment arises from high energy demands, stiff costs, and deteriorating efficiencies over time due to mass transfer limitations. This research also uncovers that creating small droplets and thus, increasing surface area, significantly raises mass transfer rates from gas to aqueous phases, thus making peroxone oxidation of toluene more efficient. Small droplets increase the effectiveness of the peroxone technique when the diffusion rate of ozone is enhanced in ultrasonic-based aerosol mist systems compared to traditional liquid-gas multiphase reactors e.g. bubble column devices.
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Keywords
ozone, hydrogen peroxide, peroxone oxidation, Ab initio, computational chemistry, hydroperoxyl radical
Citation
Parchei Esfahani, M. (2020). Kinetic and Mass Transfer of Peroxone Oxidation of Toluene Using Ultra Sonic Spray: Ab Initio Quantum Calculations and Numerical Modeling (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.