Treatment of wastewaters containing organic pollutants by the electro-fenton method

In this thesis, a detailed investigation has been carried out on the use of electro-Fenton technique for the oxidation of the some persistent organic pollutants for the sake of water remediation. This technique produces hydroxyl radicals by electrocatalytically and uses them to oxidize the organic pollutants. The overall study can be divided into three parts. Firstly, the oxidation and mineralization of some selected pesticides and synthetic dyes which are important organic pollutants were performed by the electro-Fenton process using a carbon felt cathode. The rate constants of the reaction between hydroxyl radicals and the organic pollutants were determined by the competition kinetic. The systematic analysis of the oxidation intermediates showed that the initial organic pollutants were converted into three intermediate forms; organic intermediates, short-chain aliphatic carboxylic acids and inorganic ions. Based on these intermediates, a mineralization scheme was proposed for each compound. In the second part of the study, the use of the carbon sponge (CS) cathode in the electro-Fenton process was investigated for the first time in this work. The obtained results showed that the H2O2 formation ability of CS cathode was three times higher than that of carbon felt cathode. In the third part, the effect of boron doped diamond (BDD) electrode used as anode on the efficiency of electro-Fenton method was investigated in the presence of CS cathode. The results showed that the removal of organic pollutant and total organic carbon increased prominently in the presence of BDD anode. Moreover, BDD anode affected the accumulation charecteristics of the intermediates formed during the electro-Fenton method.