Preparation Of Hollow And Janus Structured Composite Catalysts And Their Environmental Catalytic Application

With the rapid development of urbanization and industrialization,the pollution of air and water environment is becoming more and more serious.Therefore,the traditional environmental treatment materials have been unable to meet the current governance needs and it is necessary to develop new environmental treatment materials.At present,catalytic decomposition technology is the focus of research in the field of environmental pollution control.The catalytic decomposition effect can be significantly improved by designing the carrier with special structure.In this paper,hollow structure and Janus asymmetric structure of the catalyst were studied,and a variety of related structure of the composite catalyst was successfully synthesized,which applied to the catalytic decomposition of atmospheric and water pollutants.On the one hand,we prepared a series of hollow polyacrylic acid(PAA)microspheres with hydrophilic properties by distillation precipitation polymerization and etching.Then,Mn Ox/PAA hollow structure catalyst was prepared by loading manganese oxide(Mn Ox)nanoparticles onto PAA supports by in-situ growth method,and applied to the catalytic decomposition of ozone in air pollutants.The prepared composite catalysts could solve the problem of Mn Ox inactivation under high humidity through the hydrophilic action of the support PAA.At the same time,the hollow structure of the catalytic support PAA could improve the catalytic reaction efficiency by increasing the residence time of ozone in the catalyst and the contact time of ozone and catalyst.The decomposition efficiency of the synthesized PAA-60-Mn Ox-M catalyst to 20 ppm ozone reached 94.5% within 360 min at a relative humidity of 50%.When the relative humidity was 90%,the ozone decomposition efficiency could still keep at 85%.In addition,the morphology,structure and properties of the catalysts were characterized,and the catalytic decomposition mechanism and effect of ozone were discussed.On the other hand,we prepared Pt/COF-LZU1 hollow structure catalyst and Pt/COF-LZU1 bowl-shaped Janus catalyst by Pickering emulsion method,heating reflux method,etching method and impregnation method,respectively.Then,we studied their catalytic decomposition performance of methylene blue in printing and dyeing wastewater.The Pt/COF-LZU1 bowl-shaped Janus particle was successfully constructed into a self-driving motor,and its self-driving mechanism and movement behavior in hydrogen peroxide solution were analyzed.Among them,the excellent performance of covalent organic framework materials(COFs)in organic adsorption could effectively improve the local concentration of organic pollutants in the catalyst and raise the catalytic efficiency.The hollow structure of the catalyst was beneficial to contact the pollutants with the catalyst and play the catalytic decomposition performance of the catalyst.Janus asymmetric structure of the catalyst could also take the advantage of the self-driving characteristics to accelerate the mixing of liquid and the transfer rate of reactants,to improve the decomposition efficiency of pollutants.Among them,the catalytic decomposition efficiency of 150 m L 10 mg/L methylene blue could reach 94.45% by 30 mg Pt/COF-LZU1 bowl-shaped Janus catalyst at room temperature at 120 min.In addition,the morphology and structure of the two catalysts were characterized,and the catalytic decomposition mechanism was preliminarily discussed.