Preparation And Electro-catalytic Performance Of Bi₂O₃/Quartz Column Particle Electrode For The Degradation Of Phenol And Methyl Orange

Phenolic wastewater was classified as hazardous substances to focus ontreatment because of its characteristics of great harm, wide source and difficult todegrade. Dye wastewater became a hard degradable organic wastewater owing to itscharacteristics of complex components, hard degradation and big changes of pH. Anovel Bi2O3/quartz column particle electrode was prepared by thedipping-calcinations method in this paper. The graphite plate and the stainless steelplate were used as anode and cathode, respectively. Homemade particle electrodeswere used as the particle electrodes. The influence factor of the system of electricalcatalytic degradation of phenol and methyl orange were studied.Surface topography of particle electrode and structure crystal of Bi2O3wereanalyzed through the Scanning electron microscope (SEM), energy dispersive X-ray(EDS), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS)characterization methods. The results showed that the etched quartz columneffectively increased the specific surface area increasing the point contacted withBi2O3, which was good for Bi2O3loaded on quartz column. After Bi2O3was loaded,the conductive ability of particle electrode was enhanced. At the amplified to10000times, rod structures of Bi2O3can be clearly observed which significantly increasedthe area contact with pollutant. The optimum prepared condition was calcined at550oC for4h through optimizing the calcinations temperature and calcinations time.Combined with the results of degradation of phenol under different preparationconditions, the triclinic phase of Bi2O3was advantageous to the electro-catalyticproperties of the material.When the dosage of the particle electrodes was125.0g·L-1, pH was6.4and thevoltage was12.0V, the optimum degradation efficiency of phenol (initialconcentration was200.0mg·L-1) exceeded94.0%and the removal rate of the CODexceeded75.5%. When the dosage of the particle electrodes was15.0g and thevoltage was12.0V, the optimum degradation efficiency of methyl orange (initialconcentration was200.0mg·L-1) exceeded95.0%. At the same time, in order tofurther prove good electro-catalytic properties of particle electrode, the degradation of phenol in different system was studied under the optimal conditions. The resultsindicated that the degradation of phenol in three-dimensional (3D) system was25.5%higher than that in two-dimensional (2D) system. Instantaneous current efficiency(ICE) was improved obviously and the average energy consumptions were10.4kWhkg COD-1in3D system, which was about1/2times lower than that in2D system. Thereusability and regeneration of particle electrode were investigated and the resultswere good. The particle still showed electrode good electro-catalytic properties afterrunning three times and regeneration of particle electrode showed electrode goodelectro-catalytic properties calcined at550oC for1h.Finally, mechanism of enhanced electrochemical oxidation by particle electrodehas been evaluated through the capture of hydroxyl radicals in this paper. The resultsindicated that there was hydroxyl radical in oxidation degradation system. It wasproved that this is one of the main reasons. The direct oxidative degradation was alsoa major reason. Meanwhile, it was found that the electro-catalytic degradation ofphenol obeyed pseudo-first-order kinetics respecting to the phenol concentration.