Study On Degradation Of Organic Pollutants In Water By Cobalt-based Complex Oxide/Perxymonosulfate System

The sustainability of water resources has become increasingly prominent,and advanced oxidation technologies(APOs)can effectively solve this problem.Among various advanced oxidation technologies,the peroxymonosulfate(PMS)system stands out due to its ability to generate a variety of active free radicals and exhibits excellent degradation performance.Common transition metal oxides such as Co3O4 and Fe2O3 have been proved to have the effect of efficiently activating PMS.The problems of this type of catalyst are:the catalyst needs to further improve the efficiency;the catalyst structure is unstable and cannot be recycled,causing secondary environmental pollution;The degraded pollutants are single and not universal;the system cannot adapt to the real water environment.Therefore,it is necessary to construct a new system to achieve the goals of high-efficiency degradation,wide degradation range,stable structure,and practical value.To this end,this work involves two high-efficiency new cobalt-based complex oxide/peroxymonosulfate system for the degradation of various pollutants in water.1.Preparation of high-performance new cobalt vanadate/PMS system and research on degradation of dye pollutantsIn order to further increase the degradation rate of the catalyst,amorphous cobalt vanadate(CoVO)was prepared in one step by solvothermal method,and Co VO was used as the catalyst for activating PMS for the first time,and a new CoVO/PMS system was constructed to degrade various dye pollutants.Amorphous Co VO has more active sites,which can greatly increase the probability of contact with PMS molecules during the catalysis process,so as to achieve high-efficiency activation,thereby achieving high-efficiency degradation rate and removal rate of pollutants.In particular,the low-concentration CoVO/PMS system can achieve a removal rate of more than 95%for high-concentration dye pollutants(methylene blue,methylene orange,orange Ⅱ,malachite green,and rhodamine B)within 3 minutes.Compared with other cobalt-based catalyst systems,the new CoVO/PMS system designed in this part of the work has excellent degradation performance,and has universal applicability to various dye pollutants,which is conducive to wider promotion to practical applications.2.Study on the preparation and degradation of pollutants of highefficiency circulating cobalt phosphate/PMSOn the basis of ensuring high-efficiency degradation performance,in order to improve the stability of the catalyst,phosphate with high stability was selected as the research object,and the flake-shaped cobalt phosphate(CoPO)nanomaterial was prepared by hydrothermal method,and it was used as the activation PMS for the first time.As the catalyst,a CoPO/PMS system that can realize high-efficiency circulation is designed.The CoPO/PMS system can achieve the removal rate of more than 99%for all kinds of dyes under the conditions of PMS concentration and cobalt phosphate concentration of 0.2 g L-1,and the removal rate of ibuprofen,ofloxacin and norfloxacin can be achieved 99%within 6 minutes.On the basis of high-efficiency removal of pollutants,the system can achieve high-efficiency cycle performance.Even in the fifth cycle,the catalyst can still achieve the removal of more than 80%of the pollutant norfloxacin(20 ppm)in 3 minutes,and the complete degradation and removal of pollutants can be achieved within 6 minutes.The CoPO/PMS system not only has a wide range of pH applicability,but also benefits from the system’s ability to generate a large amount of high-efficiency singlet oxygen as an active species,thus common anions in water such as Cl-,SO42-,and NO3-have little effect on the degradation.The CoPO/PMS system constructed in this part of the work not only achieves high-efficiency degradation,but also has a wide degradation range and stable structure,which can achieve highefficiency recycling and has practical value.