Date of Award

Spring 1992

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering - (Ph.D.)

Department

Chemical Engineering, Chemistry and Environmental Science

First Advisor

Ching-Rong Huang

Second Advisor

Deran Hanesian

Third Advisor

Dana E. Knox

Fourth Advisor

Henry Shaw

Fifth Advisor

Su Ling Cheng

Abstract

The photo-initiated oxidation process, using hydrogen peroxide or ozone under ultraviolet radiation, has been proven to be an effective treatment method for toxic organic pollutants in wastewater. Most of the recent kinetic studies of the process were concentrated on the breakdown mechanisms of the pollutant itself. The formation and the destruction of intermediates were seldom investigated. Also the mechanisms and their reaction rate constants of free radical formation and destruction in the O3/UV or H2O2/UV reactor were seldom studied.

The objective of this research is to study the kinetics of photo-initiated oxidation of toxic organic pollutants including the formation and the destruction of the intermediates. The reaction mechanisms and their rate constants of free radical formation and destruction in the ozone (O3), O3/UV, and H2O2/UV reactor were also studied. Three refractory pollutants, nitrotoluene, naphthalene and 2,4,6-trichlorophenol were conducted in a 120 liter stainless reactor and the ultraviolet radiation source was provided by a low pressure mercury lamp located at the center of the reactor. The analysis of the concentration of pollutants and their intermediates were done by high performance liquid chromatograph (HPLC). The intermediates were identified by the GC/MS and HPLC. The kinetic models developed were verified by the experimental data taken from the reactor. The Rosenbrook Hillclimb Optimization Algorithm together with the Fourth-order Runge-Kutta method were used on a digital computer to calculate the reaction rate constants. By comparing the theoretical output concentration of pollutants with the experimental results in the CSTR processes, it is believed that the calculated rate constants and the proposed kinetic models can be practically used in the photolytic oxidation waste water treatment process.

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