Influence of Natural Organic Matter on Oxidation of Volatile Organic Compounds by the H2O2/VisUV Process
AbstractThis paper presents experimental research to determine the affect of background natural organic material (NOM) on the conversion of five (5) VOC's: 1,1,1-trichloroethane (TCA), benzene (BNZ), trichloroethylene (TCE), 1,4-dichlorobenzene (DCB), and tetrachloroethylene (PCE). Experiments were conducted using DI water and Houston tap water ([TOC] = 3.6 mg/L) as solvents. In addition, the affects of buffer form and excess hydrogen peroxide were determined. Experimental runs were conducted in a photochemical-flow-stirred-tank reactor (pcfSTR), using a 450 W visible/ultraviolet radiation source. The data were analyzed using the Prengle- Shimoda reaction rate model, yielding the reaction rate constant ka (μmols A conv/min, Lr, photon flux) for comparison purposes. Analysis of the experimental data indicated the following conclusions: 1) At the concentrations used for bicarbonate or phosphate buffer, little or no affect was observed; 2) The presence of NOM surpressed the reaction rate for three of the compounds, TCA, BNZ, and PCE at the 95 % confidence level; and 3) Excess hydrogen peroxide, beyond the stoichiometric value, increased the reaction rate constant for all five compounds. The greatest increase was seen for DCB.