The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	An investigation of the mechanism of advanced oxidation processes (AOP) involving free radicals and charged species.
Author:	Lin, Yaw-Kuen
View Online:	njit-etd1996-120 (xiv, 88 pages ~ 2.9 MB pdf)
Department:	Department of Chemical Engineering, Chemistry and Environmental Science
Degree:	Doctor of Philosophy
Program:	Chemical Engineering
Document Type:	Dissertation
Advisory Committee:	Huang, Ching-Rong (Committee chair) Lewandowski, Gordon (Committee member) Shaw, Henry (Committee member) Hanesian, Deran (Committee member) Cheng, Su Ling (Committee member)
Date:	1996-01
Keywords:	Hydrogen peroxide Advanced oxidation processes Bicarbonate ions
Availability:	Unrestricted
Abstract:	Hydrogen peroxide is a key component in Advanced Oxidation Processes (AOP). Its decomposition at different pH conditions has been studied and some interesting results were observed. When the pH value of hydrogen peroxide solution is less than 9, its rate of decomposition is independent of pH. On the other hand, in the pH range of 9-12.6, its rate of decomposition increases as pH increases, and goes through a maximum value then suddenly decreases with respect to pH. A reaction kinetic model with three rate constants in the form of beta probability function was used to describe the experimental data of the decomposition of hydrogen peroxide at various pH values. The decomposition of hydrogen peroxide at different pH conditions with UV radiation was also examined. The results showed that the higher the alkalinity, the higher the decomposition rate of hydrogen peroxide. A reaction kinetic model was proposed to describe the experimental data of the decomposition of hydrogen peroxide at various pH values under UV radiation. The decomposition of phenol at different pH conditions in the presence of H2O2/UV was studied not only in order to verify the kinetic model of the decomposition of hydrogen peroxide under UV radiation but also to investigate the mechanism of the decomposition of phenol. The results showed that the higher the alkalinity, the lower the decomposition rate of phenol. These results were in good agreement with those of the decomposition of hydrogen peroxide under UV radiation. A mechanism for the decomposition of phenol at various pH conditions was proposed. The effect of bicarbonate ion, a known scavenger of free radicals, on the decomposition of hydrogen peroxide with and without UV radiation has been investigated. The results showed that bicarbonate ion not only is a free radical scavenger but also causes an incremental increase in hydrogen peroxide decomposition. A reaction kinetic model was proposed to describe the experimental data of the decomposition of hydrogen peroxide at different bicarbonate ion concentrations. The effect of bicarbonate ion on the decomposition of phenol in the presence of H2O2/UV was studied in order to verify all kinetic models proposed in this study.