Preparation Of Porous Ceramic Particle Electrodes And Investegation On Degradation Of Nitrogen-heterocyclic Compounds

Nitrogen-heterocyclic compounds obtained great progress in scope of application and yield, due to the potential biological activity and excellent chemical modification. However, because of its carcinogenic, teratogenic and mutagenic, the nitrogen-heterocyclic compounds wastewater has high toxicity and poor biodegradability, become a difficulty in the field of wastewater treatment. Electrocatalytic oxidation has wide adaptability, can efficiently degrade the pollutants in wastewater, and is a kind of green wastewater treatment technology, attracted wide attention. The development of three-dimensional particle electrodes, not only enhanced the catalytic activity, and can effectively reduce the energy consumption, greatly promote the industrialization application prospect.This paper was based on the three-dimensional electrocatalytic oxidation technology. A novel system was founded by the preparation of porous ceramic particle electrodes and design of new packed bed reactor. The degradation process of typical nitrogen-heterocyclic compounds under three-dimensional electrocatalytic oxidation was studied, and the application in the treatment of industrial wastewater which contains nitrogen-heterocyclic compounds was also conducted. The main results are as follows:Based on the high thermal and chemical stability of ceramic materials, the CuO-Zn O/porous ceramic particle electrodes with simple preparation method, cheap and suitable for industrial application were prepared by solid phase calcination method, from using the extensive source pottery clay as substrate, cheap transition metal oxides as active component. The crystal phase, surface morphology of the particle electrodes were characterized by scanning electron microscopy, X-ray diffraction, and the stability, catalytic activity and catalytic mechanism were studied by electrocatalytic experiments.The typical nitrogen-heterocyclic compounds 2-diethylamino-6-methyl-4-hydroxypyrimidine and 2-aminopyridine were treated by three-dimensional electrocatalytic oxidation in which CuO-ZnO/porous ceramic was used as particle electrodes. The Effects of operating parameters on degradation efficiency were investigated; the degradation mechanism and dynamics were also studied. The results showed that the nitrogen-heterocyclic structure could be efficiently destroied by electrocatalytic oxidation and the two kinds of pollutants were both followed a pseudo-first-order reaction kinetic model.In view of the complexity of industrial wastewater, the degradation of ammonia, the competitive between ammonia and nitrogenheterocyclic compounds were investigated. Indirect oxidation not only could improve the degradation efficiency of ammonia, and also reduce the accumulation of(nitrous) nitrate; ammonia and the intermediates of nitrogen-heterocyclic compounds showed a strong competitive, the addition of chloride ions could significantly improve the degradation efficiency of ammonia in organic/ammonia wastewater.A novel packed bed three-dimensional electrocatalytic oxidation reactor was designed, and the flow characteristics of the reactor were studied by the residence time distribution method. The results showed that the fluid flow patterns of the reactor were between plug-flow and completely mixed flow, the fluid flow pattern tended to completey mixed flow at aeration condition, and could further research on the amplification of the reactor according to actual condition.The three-dimensional electrocatalytic oxidation technology was applied to the pretreatment of pirimiphos-methyl production wastewater and landfill leachate. A high and stable COD removal efficiency can obtain in the treatment of pirimiphos-methyl production wastewater, without any other reagents and under low energy consumption. A coagulation and three-dimensional electroatalytic oxidation combined technology was used to pretreat the landfill leachate, suspended solids and macromolecular organic compound of landfill leachate were effectively removed by coagulation, and ammonia was preferably removed in three-dimensional electroatalytic oxidation process. Application research confirmed that the three-dimensional electrocatalytic oxidation is a feasibility technology in the treatment of practical wastewater, and showed a broad application prospect.