Phenol removal from high salinity effluents using Fenton's reagent and photo-Fenton reactions

The removal of pollutants in saline medium by the Fenton's reagent needs a more detailed investigation, since the presence of chloride may inhibit or retard degradation. Phenol was used as a model pollutant and the influence of some important process variables for the removal of total organic carbon and phenol were investigated, such as FeSO4 and H2O2 concentrations, pH and salinity. The reactivity of iron cations and alternative procedures of applying UV radiation (photo-Fenton) were evaluated. Phenol was fast and completely removed by the Fenton's process even in a high saline medium (50 000 mg NaCl l(-1)). However, TOC was only moderately or poorly removed in saline media, depending on the salt concentration. When the photo-Fenton process was used, mineralization was improved and high TOC removals were observed in moderately saline media (NaCl concentration less than or equal to 10 000 mg l(-1)). For the highest NaCl concentration tested (50 000 mg l(-1)) only a moderate TOC removal was observed (50%). (C) 2004 Elsevier Ltd. All rights reserved.