Preparation Of Functionalized Conjugated Microporous Polymers And Their Adsorption Performance On Hazardous Particulate Matter And CO₂

Increasing concentrations of harmful airborne particles and excessive levels of carbon dioxide caused by human production and life have become a serious threat to the ecological environment,human health and the sustainable development of society,especially respirable particles at certain temperatures or humidity,which,once inside the human body,are likely to cause a variety of diseases.It is therefore essential to develop various functional materials to deal with harmful airborne particles and carbon dioxide.However,the trade-off between purification efficiency and air permeability pressure drop has always been a problem for a large number of porous or fibrous materials used for air purification.Furthermore,given the complexity of the actual application environment,greater demands are placed on the resistance and stability of porous functional materials.Conjugated microporous polymers（CMPs）,as a newcomer among functional organic porous materials,show great potential for both particle filtration and CO₂ adsorption due to their extended conjugated network,permanent micro/nano pore size,flexible and diverse backbone structure and a wide selection of reactive sites.Furthermore,numerous studies have shown that the introduction of heteroatoms into filter materials can increase the dipole-dipole intermolecular forces with particulate matter,resulting in a significant increase in air purification efficiency.Based on this,a series of hollow nanotube-like conjugated microporous polymer aerogel bulk materials with excellent physical and chemical stability and mechanical properties were synthesised by introducing nitrogen or oxygen into the conjugated microporous polymer backbone.The resulting materials were then subjected to a series of characterisation analyses and investigated for their purification of hazardous particulate matter and carbon dioxide adsorption properties,offering new options for air purification.The specific studies and conclusions are as follows:（1）Preparation of acid-and alkali-resistant nitrogen-containing CMPs and study of their PM capture properties.Two structurally similar nitrogen-containing bulk aerogel materials（N-CMP-1 and N-CMP-2）were obtained using 4,4’-dibromotriphenylamine,tris（4-bromophenyl）amine and 1,3,5-triethynylbenzene as reaction precursors.The N-CMPs can be used as new functional purification materials with high flux and low resistance.With a minimum pressure drop of 4 Pa at a flue gas flow rate of 0.1 L/min,they have a long-term filtration efficiency of more than 99.99%for PM_2.5.N-CMPs not only have a high PM removal efficiency in high temperature or high humidity environments,but can also filter flue gases containing acid/alkaline gases.N-CMPs have a long service life,with a simple cleaning that restores the structure to its original state,and have a high and stable recyclability for PM,especially PM_2.5 and PM₁₀.（2）Preparation of oxygen-containing CMPs and study of their PM and CO₂ capture properties.Two oxygen-containing aerogels（O-CMP-1 and O-CMP-2）with good mechanical strength and rigidity were designed and synthesised using 2,8-dibromodibenzofuran,4,4’-dibromobenzophenone and 1,3,5-triethynylbenzene as building blocks.They can be used as advanced multifunctional air purification materials.It not only captures harmful airborne particles but also possesses some CO₂ capture capability.The O-CMPs have a long-term filtration efficiency of 99.99%for PM_2.5 and PM₁₀ under high pollution conditions,and their filtration efficiency for PM_0.3 is higher than 99.10%under high humidity conditions for 4hours of continuous operation.Compared with commonly used commercial masks,its overall filtration performance has significant advantages.The filtration efficiency for PM_2.5 and PM₁₀was also above 99.98%.At 273 K and 298 K,1 bar,O-CMP-1 and O-CMP-2 showed better adsorption performance and higher heat of adsorption for CO₂.Analysis of their adsorption behaviors revealed that O-CMP-1 and O-CMP-2 at 273 K were more consistent with physical adsorption,while O-CMP-2 at 298 K showed more consistent with chemisorption of CO₂.