Influence of the Character of the Organic Pollutants on Their Oxidation Efficiency in the Fenton Process

Abstract

Industrial wastewater often contain large amounts of impurities hardly decomposable and toxic, which are difficult to remove in the purification process. Even at low concentrations, they are carcinogenic and mutagenic. Mainly they are: PAHs, PCBs, polychlorinated dibenzodioxins PCDDs and dibenzofurans PCDFs, and phthalates which more and more often are present at wastewater treatment plants. Due to the inefficiency, in most cases, of standard methods of wastewater treatment in biological, physical and chemical processes Advanced Oxidation Processes – AOPs are becoming an alternative. One of the most effective methods of advanced oxidation is Fenton process, in which highly reactive hydroxyl radicals are generated, which oxidize the majority of organic compounds into simpler, biodegradable substances. The paper presents the effectiveness of the oxidation of organic pollutants in the Fenton process. In the experiments following organic were used: an aqueous dispersion of polyvinyl acetate (Winacet) and aqueous emulsion of phthalate bis (2-ethylhexyl) (DEHP). Also description of the mechanism for their removal is given. The study showed high efficiency of the oxidation process and a significant effect of examined parameters on the efficiency of the process. Winacet from aqueous dispersion was removed as a result of the oxidation of polyvinyl alcohol which is stabilizing system: polyvinyl acetate – polyvinyl alcohol, and the destabilization of the particles of polyvinyl acetate was followed by their separation in the process of co-precipitation and sedimentation. Hydrophobic DEHP in an aqueous medium is hydrolyzing with creation of hydrophilic functional groups, which give the particles of the emulsion a negative surface charge and allow them to be effectively removed in the process of FeSO4 coagulation and co-precipitation