The Application Of Redox Couple In Organic Compounds Degradation By Photoelectrocatalysis

With the development of industry and society,the living standards of human beings have been continuously improved,which is also improved at the living environment.However,along with rasing living environment,the environmental problems brought about are becoming more and more serious.A large amount of industrial wastewater and domestic sewage are discharged without being treated,which brings about huge environmental problems.Facing the increasingly serious environmental problems,it is necessary to solve the problem of water pollution by developping efficient and safe technology.Among many water treatment technologies,advanced oxidation technology has become a research hotspot.It can deeply oxidize pollutants compared with other conventional technologies,which can product hydroxyl radicals with strong oxidizing ability.Among the advanced oxidation technologies,photocatalytic and electrocatalytic oxidation technology are mostly studied.Photocatalytic oxidation technology has been deeply studied with high efficiency,no secondary pollution and potential utilization of solar energy,but its application and development are restricted due to its low quantum efficiency.Electrocatalytic oxidation also exhibits excellent performance in the treatment of hard-degrade organic contaminants,but it takes a high cost.In order to overcome the above drawbacks,it is usually to combine multi-technology to achieve the optimal results.Especially for organic wastewater,it is difficult to be adsorbed on the surface of inorganic photocatalyst or electrode material due to the hydrophobicity of organic pollutants,which limits the degradation efficiency of organic pollutants.However,a soluble metal ion couples with strong oxidization was introduced into the solution system,which established a redox bridge between the organic pollutant and the catalyst surface and increase the contact probability of the pollutant with the active species,thereby increasing the oxidation reaction and the degradation rate.This paper mainly introduces the application of redox couples in photocatalytic and electrocatalytic oxidation techniques,and explores the synergistic effect of redox couples on photocatalysis.We mainly carry out the following parts.?1?The study on photocatalytic degradation of pollutants in anode reactor by redox couplesThe TiO₂/FTO conductive glass and TiO₂/Nickel foam was synthesized by solvothermal method.The morphology and structure of electrodes was characterized by scanning electron microscopy?SEM?and X-ray diffraction?XRD?.Different redox couples were added to the anode reactor of the system for Rh B degradation.It was found that the addition of Ce3+ was more conducive to the degradation of pollutants,and the reaction conditions were further optimized.?2?The study on photocatalytic degradation of pollutants in the addition of redox couples to anode and cathode reactorsOn the basis of the first part,in order to enhance the transfer of photogenerated electrons and suppress the recombination with holes,the addition of redox couples to anode and cathode reactors was designed in this chapter.The pollutants were degraded in the anode system,which has been discussed in last chapter.Meanwhile,the electrons can be captured by the redox couple in the cathode to degrade the pollutants.The two redox couples were separated by a double-cell photocatalytic reactor.The degradation system with Ce3+/Ce4+ redox-couple was constructed in the anode cell,and the degradation system with Fe2+/Fe3+ redox-couple was constructed in the cathode cell.The addition of two redox couples into anode and cathode have a certain promoting effect compared to the single-cell system.In the exploration of the cathode material,the gas diffusion electrode electrode was chosen as the cathode electrode material and the degradation efficiency acheived the best.The photochemical and electrochemical have a synergy effect between the anode and the cathode.?3?Design and application of continuous equipment by photoelectric catalytic for water treatmentIn the third part,a photoelectric continuous flow device for water treatment was preliminarily designed.TiO₂ supported with copper mesh was used as the anode electrode material.A photocatalytic continuous flow water treatment device was also preliminarily established,and the degradation activity was explored.The quartz fiber was selected as support for catalyst in advantages of outstanding light transmittance,well hydrophilicity in water solution,large surface area,etc.the titanium dioxide supported quartz fiber was synthesized by solvthermal method.Alcohol source and the titanium source are explored and the reaction conditions was optimized to achieve the beat activity.Finally,we carried out the experiment of wastewater degradation in the continuous system,which achieved certain effects and provided some ideas for continuous water treatment technology.