John Roth

My laboratory focuses on the following areas of environmental chemical engineering:

• Research is being carried out on chemical oxidation of pollutants. Activities include oxidation using ozone, hydrogen peroxide oxidation (Fenton's reagent), and hydrogen peroxide using complexed metals as catalysts to extend the operation pH range of the process. Application to waste waters and soil remediation are being investigated. The hydrogen peroxide decomposition kinetics were investigated for both "free" iron catalyst (Fe(II) and Fe(III) and complexed iron catalyst (Fe(II) and Fe(III) complexed with chelating agents such as EDTA as ligands. The kinetic model shown below was used to represent the reactions showing the role of the complexed ligand (L) in the model. The model fit the experimental data. Significant rates occur in the neutral pH range (6-9) as opposed to the classical Fenton's reagent which requires a pH range eliminating the need for pH adjustment.

The following notations were used:

Y1= Fe(III)-L-H	Z1= L-Fe(III)-(H)-(OH 2 )
Y2= Fe(III)-L-H 2 O	Z2= L-Fe(III)-(H 2 O)-(OH 2 )
Y3= Fe(III)-L-OH	Z3= L-Fe(III)-(OH)-(OH 2 )
Y4= Fe(III)-L-(OH) 2	Z4= L-Fe(III)-(OH) 2 -(OH 2 )

 

• Research is being conducted on the emissions of volatile organic carbons (VOCs) from surface impoundments. Investigations include the correlation of experimental Henry's Law. These correlations were made for selected organic compounds using extensive literature of currently used estimation methods was made and compared to the experimentally determined Henry's Law constants. Experimental investigation of the mass transfer coefficients has identified a laminar flow region (at low wind velocities) and a turbulent region (at high wind velocities).

• Research on the efficient production of oxygen by the reduction of ilmenite is being carried out. The kinetics of the reduction of ilmenite with hydrogen is being studied over the range of 750-1050°C. The investigation of this reduction using catalysts shows promise for increasing the rate of oxidation at lower temperatures. Extension of this work will further investigate the complex kinetics occurring at elevated temperatures. This work will be extended to obtain design data for fluidized bed reactors.