Preparation Of Conjugated Microporous Polymer Nanotube Aerogels And Membranes And Study On The Antibacterial And PM_2.5 Filtration Performance

The harmful particulate matter(PM)pollutions produced by the development of modern industry and human activities have become a globally recognized environmental problem to be solved urgently.In particular,a variety of pathogenic bacterium often coexists with PM in complex natural environments,inhalation of PM accompanied by pathogenic bacteria will bring unpredictable health hazards.The development of highly efficient porous filtration materials has always been considered an easy strategy for environmental pollution control.The limitations of traditional porous materials such as activated carbon and fiber based on the mechanism of adsorption and physical interception in the removal of harmful particulate pollutants are limited purification capacity or difficult regeneration,and they do not have the sterilization function easy to cause secondary pollution to the surrounding environment.Besides,considering the complexity of the actual environment,there should be higher requirements for the tolerance and stability of porous materials under harsh conditions(high concentration,high humidity,high temperature,etc.).Conjugated microporous polymers(CMPs)are porous organic polymers with?-conjugated molecular networks.Based on their permanent porosity,excellent stability,flexibility of structure and diversity of building blocks,the directional design and preparation of various functionalized CMPs provide a new way to solve the problem of removing harmful particulates.However,CMPs are usually synthesized as insoluble powders under irreversible kinetic control,which greatly restricts their practical applications.To address the problem of poor processability of CMPs,this topic takes the design of structural units of reaction monomers and the comprehensive regulation of physical and chemical properties as the starting point,a series of functionalized CMPs nanotube aerogels and flexible self-supporting membranes with good mechanical strength and stability were prepared by introducing different antibacterial groups or specific binding functional groups into the polymer network of CMPs.In addition,it was used as a porous filtration material for the purification of common harmful particulate pollutants in the air,and its intrinsic antimicrobial activity and the regulation of selective separation performance were studied to expand the application potential of CMPs in the rapid purification of harmful pollutants.The main contents and conclusions of this paper are as follows:(1)The preparation of conjugated microporous polymers bearing isocyanurate moiety(I-CMPs),which were synthesized using trichloroisocyanuric acid and ethynylbenzene as building blocks.I-CMPs exhibit satisfactory antimicrobial activity for Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus),and the antibacterial mechanism of I-CMPs was analyzed.The antibacterial surfaces constructed by I-CMPs show great merits of combining inhibition bacterial adhesion and sterilization,which rends the I-CMPs as antimicrobial materials with multifunctional properties,including self-cleaning,anti-adhesion,antifouling and antibacterial.(2)The aminopyridine-based CMPs nanotube aerogels(A-CMPAs)were synthesized by using 1,3,5-Triethynylbenzene and 2-Amino-3,5-dibromo pyridine as reaction precursors.A-CMPAs is an advanced multi-functional filter material,which can not only be used to purify harmful pollutants in the air,but also has intrinsic antibacterial activity,and the rapid purification rate for E.coli can reach 100%.The long-term removal efficiency of A-CMPAs for PM_2.5 was 99.57±0.19%under high concentration conditions,the removal efficiency of the A-CMPAs was up to 99.997%for PM_2.5 under high-humidity conditions.A-CMPAs can be easily regenerated,and the morphology,structure and PM removal efficiency of the regenerated A-CMPAs can basically remain unchanged.(3)The thiophene-based CMPs(T-CMPs)were synthesized using 3,6-dibromothieno[3,2-b]thiophene and 2,8-dibromodibenzothiophene as building blocks,which can be processed into aerogels and free-standing films of different shapes and sizes.T-CMPs aerogels can be used as a higher flux and low resistance multi-functional advanced nanotube filter that can be used not only to capture harmful PM in the air,but also to selectively separate oil or organic pollutants from water.The removal efficiencies of the T-CMPs nanotube aerogels for PM_2.5were up to 99.996±0.002.When T-CMPs aerogel was used for oil-water separation,the flow flux of the trichloromethane/water system can up to 1398 Lm^-2h^-1KPa^-1,and the separation efficiency of water-in-trichloromethane emulsion exceeded 96.5%.(4)The spirobifluorene-based CMPs nanofoam(TS-CMPs)was designed and prepared using 1,3,5-Triethynylbenzene and 2,2',7,7'-Tetrabromo-9,9'-spirobifluorene as building blocks.The porous frameworks of TS-CMPs are composed of?-conjugated segments bonded by covalent bonds,the rigid aromatic porous skeleton would naturally enhance their stability.After high-temperature treatment,TS-CMPS still had excellent PM capture ability.As the heat treatment temperature reaches 500?,the removal efficiency of TS-CMPs for PM_2.5 was 99.83±0.01%.TS-CMPs are a kind of high-temperature-resistant nanotube air filtration materials with high efficiency.