Electrocatalytic Oxidation Of Pollutants In Wastewater At A Graphite Anode

Anodic oxidation which is regarded as the simplest method of electrochemical advanced oxidation process(EAOPs)is extensively focused on.Electrode plays an important role in determining the efficiency of anodic oxidation.In this thesis,graphite felt was chosen as the anodic electrode material of oxygen-assisted anodic oxidation for the degradation of Methylene blue(MB),Crystal violet(CV)and Rhodamine B(RhB).The degradation efficiencies of dyes at different voltages were investigated in terms of decolorization efficiency and change of UV-vis spectra.The results show that the high voltage benefits dyes degradation.Gas chromatography-mass spectrometer(GC-MS)was applied to identify degradation intermediates of dyes.The N-demethylation,N-deethylation intermediates and several small molecular products were detected,based on which the degradation of dyes was proposed to involve the N-demethylation/N-deethylation from the N-C bond and chromophore cleavage.Key factors(pH value and initial concentration)affecting the degradation of dyes were investigated.The degradation efficiencies of dyes at the pH value of 3,6 and 11 and the initial concentrations of 25 mg/L,50 mg/L and 100 mg/L were compared.The results showed that at pH 6.0 and 1.2 V voltage,dyes were degraded at high efficiency and low energy comsuption when the concentration dyes were below 100 mg/L.The combination of ultrasonic treatment and O2-assisited anodic oxygen obtains more favorable dyes degradation than single O2-assisited anodic oxidation or single ultrasound.Such results illustrated that there was synergy between the O2-assisited anodic oxidation and ultrasonic treatment.