Controllablr Preparation Of New MnO₂ Micromotor And Removal Of Phenol Residues In Honey

Phenol as the main component of disinfection and bactericide is used as an insect repellent in flowers to drive bees to quickly concentrate and collect honey.Residual phenol can cause cumulative poisoning,anemia and dizziness in humans.Adsorption is the most effective and widely used method for removing phenol.In recent years,research on low-cost and high-efficiency adsorbents has become a hot spot,and it has become a trend to reduce adsorption costs.Inspired by natural biomotors,scientists have created a variety of artificial micromotors that imitate biological movements and were widely used in environmental governance and testing.Bubble-driven micro-nano motors such as nanotubes,Janus capsule motor required functional modification of materials with Pt precious metals,enzymes,and other catalysts,but these catalysts are either expensive or require high environmental requirements,which made the motor application limited.Therefore,low-cost and high-efficiency micromotors are still to be explored.This article aims to build a small and low-cost bubble-driven micromotor with high removal efficiency of phenol,explore the influence of time and pressure on the preparation of micromotor and the mechanism of micromotor movement,and study the feasibility experiment of micromotor removal of phenol.The removal of small molecules in food provides new methods and ideas.A controllable MnO₂ micromotor is prepared by hydrothermal synthesis method.The effect of heating time and pressure on the morphology and particle size of MnO₂ micromotor was studied.Scanning electron microscope results show that the MnO₂ micromotor has a hollow structure.Heating time and pressure affect the particle size and morphology of the micromotor,respectively.When the heating time increased from 1.5 h to 2.15 h,the average particle size of the micromotor increased from 4 μm to 10 μm.When the pressure in the reactor changes,it will accelerate the collision of ions and affect the formation of particle crystal nucleus,which will change the morphology of the micromotor.When the pressure in the reactor was increased,it was made double spherical,dumbbell-shaped and rod-shaped MnO₂ micromotor,respectively.A combination of experimental and theoretical analysis was used to systematically study the effects of fuel concentration and micromotor morphology on the driving performance of bubble driven MnO₂ micromotor.The experimental results show that the double-spherical,dumbbell-shaped and rod-shaped MnO₂ micromotors have self-driving capabilities,and the movement speeds of the three micromorphic micromotors with increasing fuel concentration are increasing.In a 10% H2O2 solution,the movement speeds of the double-spherical,dumbbell-shaped,and rod-shaped MnO₂ micrometer motors are 21 μm/s,37 μm/s,73 μm/s,respectively.In the same concentration of H2O2 solution,the resistance of the rod-shaped MnO₂ micromotor to the solution is smaller than that of the double spherical and dumbbell-shaped micromotors,which results in the fastest movement of the rod-shaped micromotors.Based on the particle adsorption technology,a new method for removing phenol from honey by bubble driven MnO₂ micromotor is proposed.Through the feasibility experiment analysis,the influence of MnO₂ micromotors concentration,phenol concentration and time on the removal of phenol by the micromotor was investigated.Studies have shown that hemisphere,dumbbell and rod-shaped MnO₂ micromotors can significantly improve the removal rate of phenol.When the micromotors concentration is 5 mg/L,the phenol concentration is 80 mg/L,and the adsorption time is 60 min,the removal rate of phenol by the hemisphere,dumbbell-shaped and rod-shaped MnO₂ micromotors can reach 73%,83% and 92%,respectively.By applying the micromotor to the removal of phenol from honey in the robinia honey,floral honey and linden honey in the market,this article proposes a method for removing small molecules in food by micromotors.The results show that the rod-shaped micromotor has the highest removal rate of phenol from honey up to 99%.In summary,this paper can control the preparation of MnO₂ micromotor based on hydrothermal method,and systematically study the movement behavior,speed and mechanism of bubble driven MnO₂ micromotor,and establish a low-cost and efficient removal method of phenol in honey.The application of motors in food provides new directions.