Fabrication Of Micropore Tube SnO₂ Ceramic Membrane Electrode And The Study On Degrading Pyridine

Electrocatalysis has a lot of advantages on degrading organic contaminant, so it receives extensive concern from domestic and foreign scholars that to produce anode materials with high electrocatalysis activity, excellent performance and long service life. But up to now, there are still some defects on conventional anode materials, which hamper electrocatalysis developing in industrial wastewater treatment.This paper aims to manufacture a kind of anode materials with high electrocatalysis activity, excellent performance and long service life, and design a reasonable reactor with electrochemical diffusion control. There are four aspects of the main research content:first of all, to study the method to modify the SnO2 substrate and to characterize it; secondly, to coat film on the SnO2 substrate to improve electrocatalysis activity and to characterize it; thirdly, to study performance of micropore tube SnO2 ceramic membrane electrode on degrading pyridine in the self-designed electrochemical reactor with the technology of electrochemistry combined with membrane filtration; finally, to study the mechanism of pyridine degradation on micropore tube SnO2 ceramic membrane electrode.The good performance of SnO2 modified electrode has been already successfully prepared by the method of solid particle sintering and doped additvies. It is found that the SnO2 substrate has many channels and the porosity is 37.22%. In these channels, the biggest aperture is 3.35μm, average pore diameter is 1.46μm and most probable pore size is 0.70μm, which has reached the microfiltration level. When trans-membrane pressure is 0.12MPa, the pure water flux of the SnO2 substrate is 4.87 mL/cm2·min-1.Micropore tube SnO2 ceramic membrane electrode has already successfully prepared by sol-gel and thermal decomposition method. Based on characterization, it is obvious that the channels of micropore tube SnO2 ceramic membrane electrode was smaller than the SnO2 substrate, the porosity factor is 4.92% lower, and the pure water flux is 7% lower. What is more, the biggest aperture is 3.05μm, average pore diameter is 1.22μm and most probable pore size is 0.20μm. Thus, micropore tube SnO2 ceramic membrane electrode is more excellent in microfiltration. In view of electrocatalysis, it reaches the highest oxygen evolution potential,2.06V. And industrial service life is 159 days under 50 mA/cm2 current density.Micropore tube SnO2 ceramic membrane electrode is served as the anode to degrade pyridine in self-designed reactor with electrochemical diffusion control. Effects of flow and static pattern, initial pyridine concentration, supporting electrolyte concentration, and current density in degrading pyridine are discussed to find the optimum reaction condition. It is clear that the flow pattern with electrochemical diffusion control is better than the static pattern without electrochemical diffusion control in removal ratio of pyridine and oxidation efficiency of pyridine. In addition, The results indicated that the removal ratio of pyridine reaches maximum under the optimal operation conditions, that are 200 mg L-1 initial pyridine concentration,10 g L-1 supporting electrolyte concentration,25 mA cm-2 current density.Transition state calculation based on the density function theory was combined with the instrumental analysis to describe the pathway of pyridine degradation, in which formic acid, malonic acid,maleic acid,fumaric acid and NO2-/NO3- are detected.