Study On The Preparation Of Conjugated Microporous Polymer Membrane Material And Its Application In Air Purification

The problem of air pollution is becoming more and more serious,seriously endangering human health,especially the particulate matter（PM）in the atmosphere,which has small particle size,large area,strong activity,is easy to attach toxic and harmful substances（such as organic volatile gases,heavy metals,microorganisms,etc.）,and has a long residence time in the atmosphere and a wide radiation range,which has a huge impact on human health and the quality of the atmospheric environment.Developing multifunctional filter materials is the main means of air purification.Conjugated microporous polymers（CMPs）are unique porous organic polymers withπconjugated framework,their large specific surface area,controllable micro/nano pore structure,excellent thermal stability,and good chemical stability make them potentially useful in the field of air purification,especially in high temperature and humidity environments.However,most of the CMPs materials synthesized by conventional methods are amorphous and powdery due to the influence of dynamic processes,resulting in poor processing performance,limiting their practical application in air filter materials.Based on this,this paper has prepared CMPs membrane materials with a macroscopic two-dimensional structure through a one-step synthesis method,and systematically explored their applications in PM,volatile organic compounds（VOCs）,and automotive exhaust purification.The main research contents include:（1）Using 1,3,5-triaethynylbenzene as the alkynyl monomer,3,3′,5,5′-tetrabromo-2,2′-dithiophene as the brominated monomer,and KBr compression plate as the template.Through Sonogashira-Hagihara cross coupling reaction,we synthesized a thiophene-based CMPs membrane material（SS-CMPs-M）.SS-CMPs-M has good hydrophobicity and lipophilicity,and the measured water contact angle（WCA）of SS-CMPs-M is 113°.The rigid aromatic structural groups in the SS-CMPs-M structure give it excellent physical and chemical stability,its thermal decomposition temperature exceeds 300°C,and it is insoluble in most organic solvents.The concentration of polymer monomer has a significant impact on the mechanical strength and filtration performance of SS-CMPs-M.Among them,SS-CMPs-M-1（solvent amount:2 m L）exhibits the best capture performance for PM,with the removal rates of PM_2.5 and PM₁₀ reaching 99.7%and 99.9%,respectively.In addition,SS-CMPs-M-1 also exhibits excellent purification effects for VOCs in air,with the removal efficiency of formaldehyde in simulated air exceeding 97%,and the AQI value of filtered gas（>500）dropping to 50.（2）Inspired by the capillary phenomenon,using 1,3,5-triaethynylbenzene and2,4,6-tribromoaniline as monomers,a"Hamburger"structured CMPs membrane（C-CMPs-M）was prepared by face-to-face constrained growth method.Its microstructure consists of smooth upper and lower surfaces and nanotubular interlayer.Due to its special structure and morphology,the interception efficiency of C-CMPs-M-1（with a membrane thickness of 0.299 mm）for PM_2.5 and PM₁₀ can reach over 99%,especially for PM_0.3,which exceeds 90%.Compared to hydrophilic filter materials,the inherent superhydrophobic properties of C-CMPs-M-1 make it still have excellent filtration efficiency and long-term stability for PM in high humidity environments,and its filtration efficiency remains basically unchanged within 10hours.In addition,due to its intrinsic lipophilic properti es,C-CMPs-M-1 exhibits an adsorption rate of 432.88%to 907.61%for different oils and unburned oil mist in vehicle exhaust,demonstrating potential application value as a vehicle exhaust purification material.