MODELING OF OXIDATION PROCESS FOR THE REMOVAL OF ORGANICS FROM WASTE WATER

Abstract

A kinetic model for the oxidation of organics in wastewater by the combination of hydrogen • peroxide and UV radiation in a completely mixed batch reactor is developed. The model is based on literature values for a series of reactions initiated by the photolysis of hydrogen peroxide by UV radiation into hydroxyl radicals, to which is added a term for the direct photolysis of the organic. The model includes the known elementary chemical and photochemical reactions, and literature reported photochemical parameters and chemical reaction rate constants are used in this model to predict organic contaminant destruction. The model is tested with data on the oxidation of a nonylphenol. The kinetics of nonylphenol destruction by hydrogen peroxide photolysis is investigated under a variety of operating conditions in homogeneous, laboratory-scale batch reactor experiments. Models with no adjustable parameters successfully accounted for radical initiation by photolysis of H202, reaction of organic targets with hydroxyl radical, and radical scavenging and recombination mechanisms. Simulations of the UV/H202 based models can be used to anticipate the kinetics of advanced oxidation involving any target compound for which there is a known apparent second-order rate constant for reaction, with hydroxyl radical. The presence of radical scavengers was successfully treated by the model, suggesting that the model can be generalized to the treatment of complex matrixes.