The Design And Application Of Self-driving Micro/nano Motor Based On Compound Polyamino Acid

Synthetic self-propelled micro/nano-motors,with their micro/nano-sized advantages and various forms of external energy converted into mechanical energy,can achieve their autonomous motion in the micro-environment.In recent decades,with the rapid development of micro-nano technology,the various micro/nano-motors have been fabricaded with various strcture,such as rods,tubes,spheres,etc.;with different driving patterns including self-electrophoresis,bubble propulsion,external stimuli like magnetic,electric or light.Micro/nano-motors have been used in many fields such as drug delivery,sensing,environmental motoring and remediation,etc.,and have vast application prospects.In particular,the microtubular motors with easy-fabrication,fast speed have been one of the hot research.However,the outer layer materials for constructing tubular micromotors are still limited and mainly include polyaniline,poly?3,4-ethylenedioxythiophene?,reduced graphene oxide,etc.,Unfortunately,their loading capacity and biodegradability are still unsatisfactory,these shortcomings limited their application in environmental govering.In this thesis,we fabricated two kinds of new microtubular motors based on the electropolymerized amino acid and explored their applications in removal of heavy metal contaminant.1.Study on the removal of mercury ions from waste water by polycysteine-aspartate/platinum microtubular motorsWith the rapid development of industry,the global water environment and air pollution problems are becoming more and more serious,which seriously threaten the health of humans and other living things.Eliminating heavy metal ion pollution in water has become a hot spot in environmental governance research.Among them,Hg²⁺is one of the most toxic metals,which is extremely harmful to the ecological environment.Once it presents in water or soil,it is difficult to be removed and is extremely harmful to the brain,kidneys and lungs.Studies have shown that Hg²⁺is easy to bind to sulfhydryl groups,and cysteine is one of amino acids containing in sulfhydryl groups.Based on this,we builtd polycysteine/platinum microtubular motors with polycysteine as the outer membrane material.The strong force between sulfhydryl and Hg²⁺was combined with the self-propulsion of the microtubular motor,thereby achieving the purpose of high efficient and rapid removal of Hg²⁺in water.Polycysteine microtubulars were prepared by template electrodeposition,and metal platinum was deposited in the tube to prepare a polycysteine/platinum microtube motor.When the concentration of hydrogen peroxide in the water was more than0.3%,the decomposition of H2O2 in the microtube motor catalyzed Pt generated a large amount of oxygen bubbles,and the motors became high-efficiency Hg²⁺adsorption machines driven by oxygen bubbles.The Hg²⁺in the solution was electrochemically concentrated on to rGO-Au modified glassy carbon electrode surface at-0.3 V,and then the concentration of Hg²⁺was quantitatively detected by differential pulse stripping voltammetry.The Hg²⁺concentration was used to calculate the removal rate of the motor.The experimental results showed that due to the self-propulsion of the micro-motor,the removal rate was improved greatly.The polycysteine microtubular motor can realize the high-efficient remoral of Hg²⁺in a short time?4 min?.2.Copolycysteine-aspartate-based/microtubular motor for the simultaneous removed of organic and inorganic heavy metals from waste/waterMethylmercury is a highly toxic and potent carcinogenic organometallic compound that is much more toxic than inorganic mercury.Any form of mercury in the environment can be converted to the highly toxic methylmercury under certain conditions.Heavy metal ions,Cd²⁺,usually cause joint pain in humans,and Pb²⁺interferes with physical activity in the body.In this chapter,a microtubular motor with the conpolymer of cysteine,and aspartic acid as the outer membrane was fabricated.After optimization,the ratio of cysteine to aspartic acid was controlled to 1:2,and the surface of the microtubular motor was compact and intact.The strong interaction between the sulfhydryl of Cys and methylmercury,and the interaction between polycarboxyl structure of aspartic acid and Pb²⁺?Cd²⁺,enabled the high efficiency removal of organic and inorganic heavy metal contaminants in water by microtube motors.In addition,the constant potential method was used to deposit nickel and platinum in the tube respectively,wherein the metal nickel was used for the magnetic control of the motor,which is beneficial to the collection of the motor;the platinum metal is used to catalyze the generation of oxygen bubbles in the H2O2 fuel solution,thereby generating the self-peopulsion of motors.The removal rate of the microtube motor to Hg,Cd,and Pb was calculated by measuring three amounts with ICP in the supernatant after adsorption by PCys-Asp/Ni/Pt microtubular motor.The results showed that the removal rate of the PCys-Asp/Ni/Pt microtubular motors could achieve nearly 100%in a short time??4min?,while that of the microtube motor under static conditions was only about 21%after 4 min.After the job of the microtube motors was finished,two motors can be quickly and completely collected by the magnet.As a kind of environmentally friendly heavy metal adsorption machine PCys-Asp microtubular motors have the advantages of high loading capacity,low cost and biodegradability,and can simultaneously adsorb organic and inorganic heavy metal pollutants in water,These microtubular motors opens up new inexpensive alternative methods to fabricate others rypes of polyamino-acid-based micromotors for different applications in the environmental fields.