Engineering Commons^™

Kinetic Study Of Decomposition Of Azo Dyes And Phenol In Advanced Oxidation Processes Reaction Mechanisms, Pathways And Intermediates, Hung-Yee Shu

Dissertations

Advanced Oxidation Processes (AOP) are an emerging technology for treatment of various hazardous organics in wastewater and groundwater. However, the kinetics and mechanisms for AOP have not been well understood. A mechanism including light intensity was studied for the decomposition of azo dyes and phenol in an AOP reactor with a 5,000 watt low pressure mercury lamp. UV light absorption is an important parameter. The effect of pH, hydrogen peroxide dosage, and dye concentration on the decomposition of azo dyes in an H₂O₂/UV reactor were also studied. Reaction pathways and intermediates of phenol oxidation by different …

Kinetic Studies Of Photo-Initiated Oxidation Of Toxic Organic Pollutants Including The Formation And The Destruction Of Intermediates, Yuan-Shen Li

Dissertations

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 …

Gas-Phase Reactions Of Methylene Chloride And Methylene Chloride-Trichloroethylene Mixture With Methane In Tubular Flow Reactor And Atmospheric Pressure, Javad Tavakoli-Attar

Dissertations

Reactions of methylene chloride diluted in methane and Argon and a mixture of methylene chloride + trichloroethylene diluted in methane and argon are studied in three flow reactors of different surface to volume ratios 4, 10.5, and 16 mm ID , atmospheric pressure and over a temperature range of 750-1000 °C. Experiments were conducted isothermally, ±5 °C over central 80% of oven length using a three zone oven. Argon was added as a diluent in order to limit carbon (s) formation. The concentration ratios of methylene chloride/methane/argon and methylene chloride/trichloroethylene/methane/argon was held constant at 1:4:10 and 1:1:40:40 respectively, throughout the …

Kinetic Modeling Of A Laminar-Flow Reactor, Shih-Hsin Chang

Dissertations

The laminar-flow reactor considering radial dispersion for a species incurring first-order homogeneous (bulk) and heterogeneous (wall) chemical reactions was mathematically modeled. The equation was solved both analytically, and by the Crank-Nicolson finite-difference technique.

The response surface method was used to obtain the optimum values of the two rate constants. The optimum values interact because the wall and bulk reactions proceed in parallel. Varied reactor diameters serve to decouple the bulk and wall reactions to locate the true values of the rate constants.

Four dimensionless variables were defined and used to characterize the reacting system. In addition, their values were shown …

Mixing Effect On Chemical Reaction In Liquid Phase, Ming-Teh Hsu

Dissertations

Mathematical models for the mixing phenomenon are proposed in this study. First model deals Newtonian and non-Newtonian fluid without chemical reaction. The new terminology " degree of mixing " is define in this model for the time-dependency of mixing toward its completeness. The velocity profile and boundary conditions are given, then the degree of mixing can be calculated by the mathematical model. The degree of mixing is influenced by fluid motion and it is function of time.

Second model deals with first-order reaction effected by mixing. A mean fractional conversion is defined to investigate the rate of bhemical reaction. Results …