Kinetics And Mass Transfer Studies Of Oxidation Of Organic Compounds In Solutions Containing Ozone With Or Without Hydrogen Peroxide

This research investigated the reaction kinetics of m-cresol, p-nitrophenol and p-nitroaniline by ozone in aqueous solution, and the kinetics of ozonation and peroxone oxidation of 2-propanol in aqueous solution. On the basis of the kinetic information, mass transport of gaseous ozone accompanied by decomposition and ozonation reactions in bubble column were investigated. The expression of the enhancement factor in ozone absorption with a first order ozone self-decomposition and a parallel second order ozonation reaction was derived. Simulations were performed of the ozone concentration and the compound concentrations during an absorption experiment, and the results compared with the measured data. In order to improve the ozone's utilization ratio, the effect of additives on the absorption rate of ozone in water and the ozonation rate of p-nitrophenol solution was also investigated. The nonyl acid and heptanoic acid were found more effective in enhancing mass transfer of ozone and degradation of p- nitrophenol. The mechanism of the mass transfer enhancement by these additives was discussed briefly.A stopped-flow spectrophotometer systems was used to study the reaction rates and orders of the ozonations between dissolved ozone and m-cresol, p-nitrophenol and p-nitroaniline in aqueous solutions of pH values varying from 2.1 to 7 at 298K. The overall ozonation reactions of m-cresol, p-nitrophenol and p-nitroaniline were second order with first order in each reactant. The stoichiometric determination indicated that three, three and four moles of ozone were required for conversion of each mole of m-cresol, p-nitrophenol and p-nitroaniline respectively. Under the same experimental condition, the ozonation rate of p-nitroaniline was the fastest and that of m-cresol was the slowest. At a given temperature of 298K, the overall ozonation rate of m-cresol, p-nitrophenol and p-nitroaniline increased rapidly with the solution pH in the range of 2.1 to 7 investigated. The destruction mechanism of aromatic compound was discussed briefly.Oxidation kinetics and degradation of 2-propanol by oxidants such as H₂O₂, O₃,...