Nonylphenols degradation in the UV, UV/H2O2, O-3 and UV/O-3 processes - comparison of the methods and kinetic study

摘要

This paper describes the results of experiments on the decomposition of selected nonylphenols (NPs) in aqueous solutions using the UV, UV/H2O2, O-3 and UV/O-3 processes. The goal of the research was to determine the kinetic parameters of the above-mentioned processes, and to estimate their effectiveness. These substances were selected because of their ubiquitous occurrence in the aquatic environment, resistance to biodegradation and environmental significance. As a result of the experiments, the quantum yields of the 4-n-nonylphenol (4NP) and NP (technical mixture) photodegradation in aqueous solution were calculated to be 0.15 and 0.17, respectively. The values of the second-order rate constants of the investigated compounds with hydroxyl radical and NP with ozone were also determined. The estimated second-order rate constants of 4NP and NP with hydroxyl radicals were equal to 7.6 x 10(8)-1.3 x 10(9) mol(-1) L s(-1) . For NP, the determined rate constant with ozone was equal to 2.01 x 10(6) mol(-1) L s(-1) . The performed experiments showed that NP was slightly more susceptible to degradation by the UV radiation and hydroxyl radicals than 4NP. The study demonstrated also that the polychromatic UV-light alone and also in combination with selected oxidizers (i.e. hydrogen peroxide, ozone) may be successfully used for the removal of selected NPs from the aqueous medium.