Synthesis Of Porous Organic Framework And Their Applications In Ammonia Sorption

Porous organic frameworks?POFs?as a new kind of porous materials,are directly obtained by polymerization of organic monomers.They have attracted a lot of attentions because of their light frameworks,diverse structures,strong design abilities,high stabilities,and high surface areas.Therefore,POFs play an important role in gas adsorption storage,photoelectricity,catalysis,bio-medicine and other fields.Ammonia is an important chemical raw material and one of the main sources of air pollutions.The nitrates produced by chemical reactions between ammonia and other substances in the air are the main components of smog.Therefore,how to effectively deal with the ammonia gas in the air is one of the main tasks of the current environmental problems.Since ammonia is both a Bronstein and a Lewis base,we designed a series of POFs with Br?nsted and Lewis acid functional groups,and tested the ammonia adsorption performance of the materials.Post-modification is a method of introducing the functional groups to the framework of raw materials without changing the skeleton of the raw material.First,we chose the porous aromatic material PAF-32,and modified it to obtain PAF-32-SO₃H with the functional group of Br?nsted acid.Then,we used the same polymerization method with PAF-32,to synthesize PAF-B-NH₂ with amino group,and then modified it to obtain PAF-B-NH₃⁺Cl^-with the Br?nsted acid functional group.According to the results of saturated ammonia vapor test,it is shown that the materials with Br?nsted acid functional groups can improve the adsorption abilities of ammonia.In situ synthesis method refers to the interpolation of the functional groups or sites directly through the polymerization step,without further processing of the material.Quaternization reaction is a kind of polymerization of quaternary ammonium salt and the operation process is simple.Therefore,we synthesized of a series of pyridine salt polymers with Lewis acid sites by Quateinization reaction,the experimental results show that this kind of materials for ammonia have good adsorption ammonia abilities.In addition,the expanded production and synthesis of PAF-C3 at room temperature and with ball milling were successfully investigated,and a series of PAFs-C3 maintained with good ammonia adsorption property were successfully synthesized.The research paved the way to low-cost synthesis of ammonia gas with excellent ammonia adsorption material,which provided the possibility for industrial mass production.