INFLUENCE OF pH VALUE ON PHENOL OZONATION

摘要

Phenolic compounds are one of the main water pollutants. Ozone is often used as an effective oxidant for wastewater purification from phenolic compounds because of its selectivity and absence of toxic by-products. Therefore, ozone reactions with phenol are the subject of many research papers. However literature data about kinetics and mechanism of this process are contradictory. In this respect, it is important to use new approaches to the investigation of kinetics and mechanism of phenol ozonolysis and also intermediates of this process. In our papers a new method for analyzing the kinetics of ozone reactions with solutions of chemical compounds in a bubble reactor was developed. The bubble reactor model involves a number of physical and chemical stages: ozone diffusion in solutions, ozone distribution between gas and liquid phases, chemical interaction of dissolved ozone with substance. The models of both kinetic and diffusion regimes were considered. The proposed method for kinetic curves processing has a number of advantages. It allows to find an analytical expression for experimental data description, which enables to determine rate constants of several stages of the process. So there is no need to solve a system of differential equations numerically. The application of this method also makes possible to reveal the criteria for distinguishing different mechanisms of the process. Kinetic analysis of data obtained and the set of other methods of investigation (UV-, IR-spectroscopy, and chromatography) could contribute to the understanding of reaction mechanisms.