Electroanalytical Study On Oxidation Treatment Of Pharmaceuticals And Personal Care Products

Pharmaceuticals and Personal Care Products (PPCPs) constitute a group of emerging contaminants which have received considerable attention in recent years.This thesis studied the degradation of 4-aminoantipyrine (4-AAP) by UV/H₂O₂ process and monitored the degradation process by an electroanalytical approach. Instead of traditional costly instrumental analysis, a sensitive method is developed for the determination of 4-AAP by utilizing a CNT film-modified glassy carbon electrode (CNTs/GCE) which showed dramatic promotion towards the electrochemical response of 4-AAP. On such a modified electrode, the peak current increased linearly with the concentration of 4-AP in the range of 5.0×10^-5-2.0×10^-3 mol/L with a detection limit of 2.6×10^-5 mol/L. Based on this electroanalytical method, the photodegradation of 4-AAP was successfully monitored. The operation parameters of UV/H₂O₂ process such as the dosage of H₂O₂ and pH value were investigated systematically, which demonstrated that the electroanalytical approach is effective to study the photodegradation of electroactive organic compounds.The electrochemical behavior of antipyrine (AP) on CNTs/GCE was studied. The peak current of AP on CNTs/GCE is increased as compared with that on GCE.The irreversible oxidation process of AP is adsorption-controlled. The current is linearly proportional to the concerntration in the range of 1.0×10^-4-2.0×10^-3 mol/L cyclic voltammetry. While the peak current increased linearly with the concentration of AP in the range of 8.0×10^-6-2.0×10^-4 mol/L when differential pulse voltammetry was applied. Then we studied the degradation of AP by UV/Fenton process was conducted and the degradation process was monitored by the proposed CNT-based voltammetry. The operation parameters of UV/Fenton process such as the dosage of H₂O₂, Fe²⁺ and pH value were investigated.A novel magnetic nanomaterials-loaded electrode has been developed for the photoelectrocatalytic (PEC) treatment of pollutants was described. Prior to electrode fabrication, magnetic TiO₂/SiO₂/Fe₃O₄ (TSF) nanoparticles were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR measurements. The nanoparticles were dispersed in ethanol and then immobilized on a graphite electrode surface with the aid of magnet to obtain a TSF-loaded electrode with high photoelectrochemical activity. The performance of the TSF-loaded electrode was tested by comparing the PEC degradation of methylene blue (MB) in the presence and absence of a magnet. The magnetically attached TSF electrode showed high degradation efficiency with desirable stability. Such a TSF-loaded electrode was applied to PEC degradation of diclofenac. Before the PEC degradation experiment conducted, the voltammetric behavior of diclofenac on CNTs/GCE was studied to make a calibration curve for diclofenac monitoring. The voltammetric response is linearly proportional to the diclofenac concentration in the range of 1.0×10^-6 to 1.0×10^-4 mol/L. The PEC degradation efficiency of diclofenac was successfully evaluated with the proposed CNTs-based voltammetry, which indicated that 95.3% of pollutant was effectively degraded after 45min PEC treatment on the magnetically attached TSF electrode.