Youssef Samet

Electrochemical degradation of waters containing O-Toluidine on PbO2 and BDD anodes

Electrochemical oxidation of O-toluidine (OT) was studied by galvanostatic electrolysis using lead dioxide (PbO2) and boron-doped diamond (BDD) as anodes. The influence of operating parameters, such as current density, initial concentration of OT and temperature was investigated. Measurements of chemical oxygen demand were used to follow the oxidation. The experimental data indicated that on PbO2 and BDD anodes, OT oxidation takes place by reaction with electrogenerated hydroxyl radicals and is favoured by low current density and high temperature. Furthermore, BDD anodes offer significant advantages over PbO2 in terms of current efficiency and oxidation rate.

Degradation of 4-chloroguaiacol by dark Fenton and solar photo-Fenton advanced oxidation processes.

This paper evaluates the dark Fenton and the solar photo-Fenton advanced oxidation processes for the treatment of solutions containing 4-chloroguaiacol (4-CG). The 4-CG was chosen as a model compound found in pulp and paper wastewater formed in the bleaching process in the pulp industry. The effects of operating parameters, including reaction time, hydrogen peroxide-to-ferrous iron molar ratio (H2O2/Fe2+), initial chemical oxygen demand (COD), pH value, and temperature, on 4-CG degradation efficiency using the solar photo-Fenton process were investigated. It was demonstrated that both processes could effectively degrade 4-CG in water and followed first-order kinetics. The degradation rate in solar photo-Fenton oxidation was much faster than that of the dark reaction. The 4-CG degradation depends on its concentration in the solution. The degradation efficiency decreases when the concentration of the 4-CG increases. Under the conditions of pH 3, H2O2/Fe2+ molar ratio 2, H2O2 16 mmol x L(-1), Fe2+ 8 mmol x L(-1), initial COD 640 mg x L(-1), reaction time approximately 24 minutes, and temperature 25 degrees C, the 4-CG and COD percent removal were greater than 80 and 89%, respectively.

Oxidation of the insecticide dimethoate by Fenton and solar photo-Fenton processes using a lab-scale continuous flow reactor

AbstractIn this study, advanced oxidation processes utilizing Fenton’s and solar photo-Fenton’s reactions were investigated for the degradation of dimethoate, an organophosphorus insecticide extensively applied in agriculture. Effect of Fe2+, H2O2, pH, and temperature on the degradation of this insecticide was studied. The kinetic rate constants (kapp) for COD removal were determined. The test results show that the degradation of dimethoate proceeded rapidly at pH value of 3.0. kapp enhanced with the increase of initial Fe2+ concentration and H2O2 dosing rate. However, higher levels of Fe2+ and H2O2 also inhibited the reaction kinetics. kapp decreased with the increase of initial dimethoate concentration, but increased with the increase of temperature. The activation energy for COD removal by Fenton oxidation, derived from the empirical Arrhenius expression, is 21.38 kJ mol−1. A noticeable kapp increase (∼50%) was obtained when using the solar photo-Fenton process, which means about 50% gain of H2O2.