| At present,the rapid development of social industrialization and modernization promotes the development of society,while continuously improving people's lifestyles and living standards,the accompanying environmental problems have become increasingly serious,such as excessive energy consumption causing CO2 concentrations in the atmosphere which has led to global warming and seawater acidification;the wantonly use and disposal of toxic and harmful chemicals has seriously polluted the soil,the atmosphere and the water environment.These environmental problems have seriously affected people's quality of life and physical health.In the face of the urgent changes in environmental pollution,traditional pollution prevention and control strategies have become inadequate,for example,industrial CO2 emissions are absorbed using liquid amine.The method not only consumes a large amount of energy during desorption,but causes equipment corrosion damage.Therefore,it is of great social and economic significance to develop novel pollution-control methods and environmental materials that are energy-saving,low-cost and environmental friendly.Microporous organic polymers are a class of lightweight materials with high specific surface area,modifiable functions,and controllable pores.In recent years,they have been continuously exerting their excellent material properties in the environmental field and exhibit huge potential application prospects for the development of green materials with environmental protection,energy saving and low cost.In this paper,from the perspective of molecular structure design,a rigid heterocyclic structure is taken as the core building unit,and a series of multi-functional conjugated microporous organic polymers are prepared by oxidative coupling method,which is mild,efficient and controllable.P-BCPBTZ and P-TCPBTZ materials were prepared by taking the rigid heterocyclic benzothiadiazole with two-armed structure as the core unit,and adding carbazole functionalgroups to construct the "D-A" structural molecular unit by low-cost oxidative coupling reaction.The two materials have excellent heat resistance,and the 5%.thermal weight loss temperature can reach over 470?,which is conducive to industries applications in high-temperature operations.The specific surface areas of P-BCPBTZ and P-TCPBTZ are 642 m2g-1 and 1067m2g-1,respectively;the micropore content are 0.021 and 0.21,respectively.In terms of gas adsorption,the adsorption capacity of P-TCPBTZ to CO2 is up to 7.74wt%.The "D-A"molecular structure endows the material excellent fluorescence properties,through the study of the fluorescence detection of pollutants nitroaromatics,both materials can show good recognition ability and can effectively perceive the existence of nitroaromatics at low concentration(0.1M).By comparing with other aromatics,it is found that materials have a certain fluorescence selection mechanism for nitroaromatics.After the summary of the above work,the pore structure and properties of the material are further explored and optimized through the optimized design of the molecular structure.The rigid heterocyclic triazine ring of the three-arm structure is taken as the core unit to expand the spatial distortion of the structure and further enrich the functional groups.P-TCBPT and P-TBCBPT materials were both successfully prepared by oxidative coupling reaction.Through the thermogravimetric test,the 5%thermal weight loss temperature of the two materials exceeded 300?,showing excellent heat resistance.The specific surface areas of P-TCBPT and P-TBCBPT are 543 m2g-1 and 1720 m2g-1,respectively;and the corresponding micropore content are 0.142 and 0.274,respectively.Through the gas adsorption and desorption test,the adsorption capacities of CO2(lbar/273K)by P-TCBPT and P-TBCBPT can reach 8.63wt%and 10.8wt%.At the same time,the heat of adsorption of P-TBCBPT is 28.5 kJ mol-1,which shows a great interaction with CO2 molecules.Based on previous work,the two materials both showed a visually distinguishable effect on the fluorescence detection of nitroaromatics at low concentrations(0.1M),with the fluorescence quenching rate of above 90%.Further the detection of nitroaromatics at ultra-low concentration(0.01M),the both of materials can still maintain a high recognition sensitivity,the fluorescence quenching rate is more than 50%,and compared with other aromatics,the materials have excellent fluorescence selection mechanism for nitroaromatics.In summary,comparing with the previous work,through further optimization of the design for molecular structure,the pore structure(specific surface area,micropore content,etc.)and functional performance(gas adsorption capacity,fluorescence detection sensitivity,etc.)of the materials have been enormously optimized and improved. |
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