| Removal of the organic pollutants during wastewater advanced treatment process has become a research hotspot in the field of water treatment. Three dimensional(3D) electrocatalysis, which could solve the problem of low current efficiency and high energy consumption, has drawn more and more attention. Development of novel, high-efficiency, cost-effective particle electrodes would be significant in pracical utilization of 3D electrocatalysis technologies. In views of “using waste to treat waste”, this thesis has explore to prepare particle electrodes using steel slag as a raw material. Modify the particles in order to improve the catalytic performance. This research detect the physicochemical property of these novel particles, and using these particle as particle electrodes in novel 3D electrocatalysis reactors that self-designed. The performance and mechnism of the particles in removing organic pollutants and treating practical wastewater has been studied in this thesis. The possibility of practical utilization in advanced wastewater treatment of these particles has been discussed. Based on the contents mentioned above, some mainly works are carried out.At first, a orthogonal experiment were designed to explore preparing method of steel slag particle electodes(SSPEs). Critical fabrication parameters were anyluzed. The resulting particle electrodes were then characterized by some equipments. Subsequently, performance and cyclic performance of the particle electrodes was investigated. It was found that the best preparation conditions of steel slag particle electrodes are raw materials ratio 5:4:1(steel slag: clay:pore-forming agent), calcination temperature 1000 and calcination time 30 min. Furthermore, the particles has complicated chemical constituents and structures. It mainly contains O、Ca、Fe、Si、Mg、Al、Mn in the forms of oxides. The particles are magnetic, and the saturation magnetic induction of the particles are 1.6389 emu/g. In addition, 3D electrocatalysis system with steel slag particles has a better performance than 2D-system and 3D system with ceramic particles. When the particles were cyclic used, the Rh B removal rate decreased for about 20% after the first cycle, and then remained stable at about 39% in latter six cycles.Some experiments were conducted in a static 3D electrocatalysis reactor in order to investigate the influence factors and kinetics of SSPEs degrading Rh B. Other experiments were conducted in order to investigate the mechanism of SSPEs remove organic pollutants in water. It was found that the best conditions for degrade Rh B in this system are applied voltage 5 V, amount of SSPEs 15 g, electrode spacing 4 cm, electrolyte concentration 0.15 mol/L, initial Rh B concentration 5mg/L and initial p H value 4. The Rh B degradation process fitted well with the pseudo-first-order kinetics formula according to the Langmuir-Hinshelwood model. Furthermore, Fe reduced in the particles after degrading Rh B according to the XPS spectra. It can be speculated that Fe reacted with OH-, and then Fe(OH)3 was generated. It was also found that 3D electrocatalysis system with SSPEs has a better ability in generating hydroxyl radicals than 2D electrocatalysis system.It is because 3D electrocatalysis system with SSPEs could generate hydroxyl radicals by electrochemical oxidation as well as by electro-Fenton oxidation. Furthermore, aeration could improve catalytic performance of the 3D system according to the aeration experiment.The static reactor was ameliorated and the SSPEs were surface-modified through a ultrasound impregnation-calcination method in order to further improve the catalytic performance of the SSPEs. The surface-modified SSPEs were all utilized in the ameliorated static 3D electrocatalysis reactor for degrading Rh B. Orthogonal experiment and single-factor experiment were designed. The best loading metal, best loading conditions were selected by investigate the degradation rate of Rh B. Result showed that the most suitable metal loading on the SSPEs was Mn, and the best condition of Mn loading were concentration of impregnation solution 20%, ultrasound impregnation time 1.5 h, calcination temperature 400 and calcination time 1h. The surface-modified SSPEs have great improvements on catalytic performance, ability of generating hydroxyl radicals and cyclic performance. The best conditions for the system to degrade Rh B are applied voltage 5 V, amount of SSPEs 15 g, electrolyte concentration 0.15 mol/L, initial Rh B concentration 5mg/L and initial p H value 4. The degradation process also fitted well with the pseudo-first-order kinetics formula according to the Langmuir-Hinshelwood model. Furthermore, aeration still could improve catalytic performance of the 3D system with surface-modified SSPEs.Finally, a dynamic 3D electrocatalysis reactor was fabricated for investigating the performance of surface-modified SSPEs in advanced treating practical oil wastewater from Daqing oilfield. It was found that the best condition for the dynamic reactor to advanced treating oil wastewater are applied voltage 5 V, amount of particle electrodes 75 g and hydraulic retention time 2 h. Furthermore, the dynamic reactor could remove over 85% TOC in oil wastewater in 2 h, and the treating process fitted well with the pseudo-first-order kinetics formula according to the Langmuir-Hinshelwood model. Electric energy efficiency of the reactor was 282 mg TOC/k Wh. |
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