Preparation And Application Of Micro-nano Hierarchically Tubular Motor

Adsorption is a widely used wastewater treatment method,but the traditional adsorbent has not high adsorption efficiency and selectivity.We combined micromotor with molecular imprinting technology in order to prepare both efficient and selective adsorbent materials.Enzymatic oxidation is an effective method for wastewater treatment.However,free enzymes are easy to inactivate and have poor stability,which makes it difficult to recycle.Immobilized enzyme technology can effectively solve this problem.We combined immobilized enzyme technology with micromotor and prepared high activity immobilized enzyme micromotor.Specific research work is carried out from the following two parts:1.Using natural kapok as biological template,molecularly imprinted polymer micromotor?MIPs-MgAl-LDH/Mn₃O₄ micromotor?was successfully prepared.XRD,SEM,EDS-mapping,TEM,FT-IR,N₂ adsorption-desorption and TG-DTA were tested and analyzed.The results showed that the MIPs-MgAl-LDH/Mn₃O₄ micromotor retained the hollow tubular asymmetric structure of kapok.The surface was loaded with MgAl-LDH nanosheets and ultra-thin molecularly imprinted membranes.The MIPs-MgAl-LDH/Mn₃O₄ micromotor had micro-nano multi-layered structure with a specific surface area of 211.9 m² g^-1 and many adsorption active sites.The adsorption properties of doxycycline by MIPs-MgAl-LDH/Mn₃O₄micromotor were studied.The results showed that in the absence of hydrogen peroxide,the adsorption equilibrium of MIPs-MgAl-LDH/Mn₃O₄ micromotor reached after 72 hours,and the maximum adsorption capacity of doxycycline was 209.33 mg g^-1;In 2%H₂O₂ solution,the adsorption equilibrium of MIPs-MgAl-LDH/Mn₃O₄ micromotor reached balance only 7hours after adsorption,and the maximum adsorption capacity was 224.23 mg g^-1.Therefore,the design of the micromotor greatly improves the adsorption efficiency of the adsorbent.In addition,the adsorption of doxycycline by MIPs-MgAl-LDH/Mn₃O₄ micromotor shows good specificity and repeatability.Finally,the motion performance of MIPs-MgAl-LDH/Mn₃O₄micromotor was studied.In a certain range,the speed of the motor increased with the increase of the concentration of hydrogen peroxide.When the concentration of hydrogen peroxide was10%,the speed of the motor reached 197.86?m s^-1.After magnetizing the MIPs-MgAl-LDH/Mn₃O₄ micromotor,the adsorption performance of the magnetic MIPs-MgAl-LDH/Mn₃O₄ micromotor was almost unaffected with good magnetron control characteristics and recycling performance.2.ZIF-67/MoS₂ immobilized laccase magnetic micromotor and ZIF-67/NiAl-LDH immobilized horseradish peroxidase magnetic micromotor were successfully synthesized using kapok as biological template.The morphology and physical properties of the synthesized samples were tested and analyzed.The results showed that immobilized enzyme magnetic micromotors retained the hollow tubular structure of kapok.In addition,the micromotors were loaded with MoS₂ nanosheets/NiAl-LDH nanosheets and rhombic dodecahedron ZIF-67.Transmittance images showed that ZIF-67 was successfully coated with enzymes,and the whole material had a micro-nano multi-level structure.The specific surface area of ZIF-67/MoS₂ immobilized laccase magnetic micromotor and ZIF-67/NiAl-LDH immobilized horseradish peroxidase magnetic micromotor reached 511.6m² g^-1 and 499.4 m² g^-1,respectively.The enzymatic properties of two immobilized enzyme magnetic micromotors were studied.The results showed that the specific activity and recovery of laccase were the highest when the amount of laccase was 5 mg,which were27840 IU/g and 376.2%respectively.The optimum pH value and temperature of immobilized laccase magnetic micromotor were 4 and 40^oC,respectively.It possessed excellent pH stability,temperature stability and reusability.When the amount of horseradish peroxidase was 10 mg,the activity and activity retention value of horseradish peroxidase were the highest,456.82 and 72.21%respectively.The optimum pH value of immobilized horseradish peroxidase magnetic micromotor was 7,which had good reusability.Finally,the kinematic performance of two immobilized enzyme magnetic micromotors was studied.ZIF-67/MoS₂immobilized laccase magnetic micromotors and ZIF-67/NiAl-LDH immobilized horseradish peroxidase magnetic micromotors both have good kinematic performance and magnetic control characteristics,and can achieve high-efficiency degradation of pollutants and magnetic recovery and reuse.