Kinetic Modeling of the Aging pf PE Pipes for the Transport of Water Containing Disinfectants [PE]

This article deals with the kinetic modelling of reactions between chlorine dioxide used as disinfectant and components of stabilized polyethylene pipes used for the transport of drinking water. From the study of antioxidant thickness distribution after accelerated aging (20 or 40°C, high concentrations of chlorine dioxide) or natural aging (up to 15 years of use with low concentrations of chlorine dioxide), a kinetic model is proposed. It takes into account two reactions : phenolic antioxidant-chlorine dioxide and polyethylene-chlorine dioxide, and diffusion of both reactants : antioxidant and chlorine dioxide. The model is in good agreement with experimental results of accelerated aging but requires further improvements in the case of natural aging where physical antioxidant loss becomes important. Key words : Polyethylene pipes; Drinking water; Chlorine dioxide, Aging; Kinetic modeling.