Preparation And Application Of Iron-based Multi-level Micromotors

Micromotor is a micro-scale energy conversion device.Because its autonomous movement ability,the components that make up the micromotor could fully contact and collide with trace pollutant molecules in the water body,and increase the probability of mass transfer,so as to enhance the catalytic activity of each unit of the micromotor,and then improve the sensitivity of water pollutant molecule detection and degradation removal efficiency.Aiming at the low detection sensitivity and degradation efficiency of trace organic pollutants in the current water environment,this paper innovatively combines the autonomous movement of the micromotor with recognition sensing and degradation removal,and then designs a three-dimensional multi-hierarchical multi-functional micromotor based on iron compounds.The microstructure,motion behavior,recognition sensing,degradation removal,and recognition sensing and degradation removal mechanisms of the two micromotors were explored in detail.The specific research work is as follows:1.Using hydrothermal synthetic MnO₂ microspheres as the carrier,then Fe₃O₄nanoparticles and HKUST-1 nanowires were cleverly constructed on the surface of Mn O₂microspheres,so a three-dimensional multi-hierarchical Fe₃O₄@Mn O₂@HKUST-1 magnetic micromotor was obtained.XRD,XPS,IR,SEM and so on were used to analyze the microstructure and morphological characteristics of materials.In addition,the movement speed of the micromotor was large,which could reach 99±2μm s^-1 in the presence of 5%H₂O₂,and the excellent magnetic property made the micromotor movement could be easily controlled.The large specific surface area resulted in fully exposed active sites,which exhibit excellent catalytic activity for simultaneous detection and degradation of hydroquinone.Based on the excellent peroxidase-like activity of the micromotor and the strong reduction of hydroquinone,a sensing platform for colorimetric recognition of hydroquinone was constructed with a limit of detection of 0.94μM and a linear range of 1 to 280μM.Moreover,the micromotor still showed strong specific recognition of hydroquinone in the presence of a variety of inorganic interfering ions.The mechanistic study of colorimetric detection of hydroquinone had shown that a large amount of·OH was produced in the chromogenic system.Based on the autonomous movement of the micromotor and robust peroxidase-like activity of each component unit,the efficiency of micromotor degradation removal of hydroquinone was further studied.When the p H was 5 and the H₂O₂ concentration was 3%,the maximum degradation efficiency of hydroquinone in Fe₃O₄@MnO₂@HKUST-1 magnetic micromotor was 96.92%.The above results show that the Fe₃O₄@Mn O₂@HKUST-1 magnetic micromotor has a good application prospect in water treatment applications.2.The MoS₂ microtube was used as the carrier,the CuFe₂O₄@Mo S₂ heterojunction was reasonably designed,and finally the SDS was modified on the surface of Cu Fe₂O₄@Mo S₂ to obtain a three-dimensional multi-level SDS-Cu Fe₂O₄@Mo S₂ tubular micromotor with good dispersibility.The microtubule structure and morphological characteristics of micromotors were analyzed by XRD,IR,SEM,TEM and etc.Due to the large relative molecular weight of the micromotor,its movement speed was small,and when the H₂O₂ concentration was 15%,the movement speed reached 186.7±5.7μm s^-1.The micromotor had a large number of marginal active sites,and a more negative zeta potential after modification,resulting in excellent affinity with the substrate TMB.Combined with the specific binding of micromotors to glyphosate,a colorimetric detection system with high sensitivity was established,detection limit was 0.0398 mg L^-1 and a low concentration linear range was 0.0001 mg m L^-1-0.003 mg m L^-1.In addition,in the presence of various interfering agents,the micromotor also showed good specific recognition of glyphosate.Based on robust peroxidase-like activity and photocatalytic activity of micromotor,the performance of micromotor light-assisted Fenton/Fenton-like process in degrading glyphosate was studied,and the maximum degradation efficiency was 92.6%.In addition,the micromotor after degradation recovery had better reusable performance.The above results show that SDS-Cu Fe₂O₄@Mo S₂ tubular micromotor has good photo-assisted Fenton/Fenton-like catalytic activity,which has a good application prospect in the treatment of organic pollutants in water environment.