Degradation of phenolic pollutants using KrCl and XeBr excilamps in the presence of dye: A comparative study Original Research Article

Phenolic compounds removal in colourless and non turbid water systems has been widely studied. In this work, the oxidation of phenol and 4-chlorophenol in the presence of the dye methyl green has been studied using a combined advanced treatment based on photodegradation with UV radiation generated by KrCl and XeBr excimer lamps in the presence of H2O2. Experiments suggest that pollutants removal is practically independent of the presence of the dye in the reaction matrix. The KrCl excilamp was found to require a shorter treatment period than the XeBr to totally degrade the phenolics. Increasing phenol or 4-chlorophenol concentrations has a negative influence on methyl green degradation, whereby maximum dye degradation rate is achieved when there are no phenolic compounds in the aqueous matrix. It was also evident in the experimental range tested, that the H2O2:phenolic compound molar ratio does not significantly influence the removal of phenol and 4-chlorophenol using both excimer lamps. Nevertheless, the removal of methyl green is improved with high molar ratios. Based on the experimental data, a pseudo-first order kinetic model for the KrCl excilamp and a pseudo-second order for the XeBr were proposed. A good correlation between experimental and calculated data was obtained.