Application d’un Procédé Adsorption- Electrochimique d’oxydation avancée au Traitement des Polluants Complexes

Abstract

The objective of this study is to develop a combined method of adsorption and Electro-Fenton oxidation for the removal of Amoxicillin (AMX) and Paracetamol (PCM) from synthetically prepared solutions. The biosorbent, derived from Brahea Edulis palm leaf fibers (FBE), was employed as an adsorbent agent in the first stage of treatment for each pollutant individually. The FBE biosorbent was characterized using FTIR, SEM, BET, and XRD, revealing an irregular, rough surface morphology with a well-formed porous structure and a specific surface area of 124 m²/g. The optimal conditions for the adsorption of AMX were found to be at pH 6, with an FBE concentration of 6 g/L, an initial adsorbate concentration of 50 mg/L, and a contact time of 90 minutes, achieving a removal efficiency of approximately 58%. In contrast, the removal rate for PCM by adsorption reached over 89%. Thermodynamic analysis indicated that the adsorption of AMX is spontaneous and endothermic, with a reaction enthalpy of 37.155 kJ/mol, while the adsorption of PCM is spontaneous and exothermic, with an enthalpy of 17.085 kJ/mol. The kinetic study showed that the adsorption process of both pharmaceutical pollutants follows a second-order model. Additionally, the adsorption isotherm modeling demonstrated that the Langmuir model best describes the adsorption process for both AMX and PCM, compared to the Freundlich and Temkin models. In the second part of this study, the feasibility of applying the Electro-Fenton process for treating AMX and PCM in an aqueous solution was assessed. The optimal conditions for the Electro-Fenton reaction, using a platinum anode and a carbon felt cathode, were determined as follows: a ferrous iron concentration of 0.1 mM, a current intensity of 300 mA, and a pH of 3, with an initial concentration of 0.13 mM for AMX and 0.33 mM for PCM. Under these optimal conditions, the degradation rates reached 96% for AMX and 94% for PCM, with energy consumptions of 8.25 kWh/kg for AMX and 8.42 kWh/kg for PCM. In the final part of the study, the treatment of these pollutants using the ElectroFenton process followed by FBE filtration was evaluated. The degradation efficiencies achieved by the Electro-Fenton process were 96% for AMX and 94% for PCM. SEM analysis of the FBE after filtering the oxidized solutions revealed that iron had been adsorbed into the pores of the FBE. The presence of iron in the adsorbent pores indicates that FBE can be effectively used as an adsorbent to remove the residual iron generated by the Electro-Fenton process.