Synthesis Of Copper Oxide Nanoparticles And Its Application In Catalytic Degradation Of Rhodamine B

With the rapid development of industrial society,environmental issues have gradually attracted the attention of the public.Among them,how to achieve efficient and deep degradation of industrial wastewater has been a hot research topic in the field of wastewater treatment.The advanced oxidation technology degrades organic pollutant molecules by generating strong oxidizing radicals and converts them into water and carbon dioxide,thus achieving a harmless treatment of wastewater.Among them,the heterogeneous catalytic technology using transition metal oxides as catalysts is widely used due to its mild reaction conditions,high degradation efficiency rate and fast reaction speed.It is important to develop heterogeneous catalysts with regulated structure,surface properties and compositions,thus their catalytic performance can be enhanced.The present work is composed of two parts.In the first part,nanosized copper oxide with high oxygen vacancy content was prepared by the co-precipitation method and its light-assisted catalytic degradation of rhodamine B(Rh B)was systematically investigated.In the second part,copper oxide doped with other metal ions were synthesized and studied for their light-assisted catalytic degradation of Rh B by PMS.In the first part of the study,the copper oxide prepared without the addition of structure-directing agent was in the form of long,uneven flakes.While the copper oxide prepared by co-precipitation using sodium citrate as the structure-directing agent was in the form of needles and pikes of uniform size and had a higher specific surface area,which was conducive to improving the adsorption of the oxidant PMS and organic pollutants and hence the degradation efficiency of the reaction.Under neutral conditions,the efficiency of photo-assisted activation of PMS to reduce rhodamine B could reach 96% within 20 min.Structural characterization and semiconductor performance tests showed that the copper oxide had high charge transfer efficiency,reduced diffusion impedance,abundant oxygen vacancies and abundant active sites,as well as a wide workable p H range and high cycling stability,maintaining a degradation rate of over 90% after four cycles.The results of the trap experiments showed that there were three main reactive species in the Cu O/PMS reaction system,namely superoxide radicals,vacancies and sulphate radicals,and the reaction mechanism was tentatively deduced.In the second part of the study,copper oxide composite catalysts doped with different transition metal elements were synthesized using the same material preparation method and their microstructure and performance in the light-assisted activation of PMS for rhodamine B degradation was investigated.The microstructure of copper oxide was significantly changed after doping with other metal elements,especially the cobalt doping greatly increased the oxygen vacancy content and enhanced the ability of the catalyst to generate photo-generated electrons and decreased the photo-generated electron-hole complexation rate,enhancing the photocatalytic performance of the material.rate.The prepared cobalt-doped copper oxide catalysts were also able to maintain high catalytic activity over a wide p H range.The results of the trap experiments showed that singlet oxygen,superoxide radicals,cavities,sulphate radicals and hydroxyl radicals were all involved in the degradation reaction in this system.The introduction of cobalt ions accelerated the charge transfer rate between different valence states of copper ions in the catalyst and thus accelerated the formation of radicals.The prepared cobalt-doped copper oxide catalyst also exhibited strong cycling stability,which indicated that it has a great potential for further application in the field of photo-assisted activated degradation of organic pollutants.