DEVELOPMENT OF FENTON-LIKE REAGENTS FOR THE DEGRADATION OF PHTHALATE ESTERS

Abstract

This study involved the development of Fenton- like reagents (Mn2+/H2O2 and Cr2+/H2O2) for the degradation of phthalates esters – dimethyl phthalates (DMP), diethyl phthalates (DEP) and diphenyl phthalate (DPP). The degradation efficiency of phthalate esters (initial concentration of 20 mgL-1) by the newly developed reagents was conducted at different time intervals, the pH was adjusted to 3.0, the reaction mixtures were extracted and analysed by High-Performance Liquid Chromatography (HPLC). The H2O2 concentration was set at 100 mgL-1, and 10 mgL-1 for both Mn2+ and Cr3+. The results showed that the reagent, Mn2+/H2O2 degraded DMP completely within 20 minutes of the experiment, while 3.0 mgL-1 of DEP and 4.88 mgL-1 of DPP remained. At 30 minutes, DEP was found to be completely degraded with 4.84 mgL-1 of DPP remaining. In the same vein, the second reagent (Cr2+/H2O2) recorded 100 % efficiency on DMP within 20 minutes while that of DEP did not reach 100 % efficiency until 60 minutes. In this case, the reaction time of 20 mgL-1 DMP and DEP with this reagent is 20 minutes and 60 minutes respectively. Furthermore, it could be deduced that 30minutes is sufficient for complete degradation of 20 mgL-1 DMP and 20 mgL-1 DEP with Mn2+/H2O2 reagent while the degradation of 20 mgL-1 DPP took 60 minutes. For Cr3+/H2O2 reagent, the reaction time for the complete degradation of DMP and DEP was 30 and 60 minutes respectively. These newly developed reagents Mn2+/H2O2 and Cr2+/H2O2 are very effective and efficient for the degradation of phthalate esters thus, recommended for the degradation of liquid wastes containing these hazardous compounds.