| Porous Organic Frameworks(POFs)are porous organic polymers composed of light non-metallic elements such as C,H,O,and N.In recent years,they have been widely studied in the fields of gas adsorption,gas storage and separation,and heterogeneous catalysis.As one of the porous organic framework materials,porous aromatic framework materials(PAFs)based on aromatic monomers have great potential for adsorption and photocatalytic degradation of organic pollutants due to their high specific surface area,strong physical and chemical stability,good photocatalytic property and low cost.However,there is still much room for improvement in the preparation of PAFs,especially in terms of cost reduction and performance improvement.Therefore,it is necessary to further explore the preparation strategies of porous aromatic skeleton materials,such as modification of materials by using mineral template.Clay minerals are a class of hydrous aluminosilicate minerals with layered structure.As an important component of rock and soil,clay minerals are widely present in the earth’s surface system.Because of its abundant reserves,strong ion exchange performance,large specific surface area and chemical stability,it shows excellent adsorption performance for organic pollutants and heavy metal ions.As a common clay mineral,montmorillonite not only has the advantages of the above clay minerals,but also has been reported to significantly enhance the adsorption and catalytic properties of the material after compounding with the material.In this work,we are committed to using layered clay minerals to modify porous aromatic framework materials,exploring the preparation methods of composites with higher adsorption and photocatalytic properties,and then exploring the performance and application of the composites in the treatment of organic pollutants.Firstly,based on the synthesis principle of Scholl Reaction,we modified the porous aromatic framework material PAF-45 with montmorillonite template to obtain a new porous aromatic framework material(PAF-Mt).Compared with PAF-45,PAF-Mt still maintains a stable skeleton structure,π-πelectron conjugated system of multi-benzene ring and inherent microporous structure,especially its specific surface area and photocatalytic activity are significantly improved.As a photocatalyst,PAF-Mt can successfully degrade quinolone antibiotics,tetracycline antibiotics and chloramphenicol antibiotics under visible light irradiation.Compared with PAF-45 without montmorillonite template modification,the catalytic degradation efficiency of PAF-Mt increased by 3.2-7.6 times.In order to further improve the performance of the new porous aromatic framework material for the treatment of organic pollutants,we superimposed the hydrothermal method to further remove the silica component in the unremoved template of PAF-Mt,and obtained a porous aromatic framework material with better adsorption performance(PAF-Mt-Free).The specific surface area of PAF-Mt-Free is as high as 968 m~2/g,which is313 m~2/g higher than that of PAF-Mt.In the experiment of adsorbing volatile organic pollutants,the adsorption efficiency of PAF-Mt-Free for benzene,toluene,chlorobenzene and nitrobenzene increased by 10.9%,18.5%,11%and13.3%respectively compared with PAF-Mt.In addition,under visible light irradiation,PAF-Mt-Free still maintains similar catalytic efficiency to PAF-Mt.In this paper,the photocatalytic and adsorption properties of porous aromatic skeleton materials were improved by using montmorillonite as a template agent to modify porous aromatic skeleton materials,and the modification of porous aromatic skeleton materials at low cost was realized.It shows that the modification of porous aromatic skeleton materials by layered mineral template is a novel,promising,cheap and feasible strategy for obtaining large specific surface area materials. |
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