| The antibiotics present in wastewater are difficult to remove through processes such as sewage treatment plants.After accumulation and recycling,it will affect human health and damage the balance of ecological environment.How to quickly and efficiently remove antibiotics from wastewater has become an important concern for human sustainable development.The new porous metal organic framework material has attracted a lot of re search attention because of its many advantages.This paper has done some research on its synthesis method and functional modification and its application,and found that the use of microwave-assisted synthetic materials changes in properties.Moreover,th e properties of materials modified by in-situ introduction of functional groups are also changed,and the adsorption properties are significantly improved.In this paper,firstly,ferric chloride and terephthalic acid are used as reactants,and an appropriate amount of acetic acid is added to accelerate the formation of crystals,and N,N-dimethylformamide is used as a solvent and then all placed in reactor and a microwave special glass container.The MIL-101material was synthesized under different reactio n time;then,the ferric chloride hexahydrate and 2-aminoterephthalic acid are used as reactants,and an appropriate amount of acetic acid was added,and N,N-dimethylformamide is used as a solvent.The NH2-MIL-101 material was successfully synthesized by introducing an amino group in situ in a high pressure reaction vessel and a microwave special glass vessel at different reaction times.The four materials prepared were characterized by XRD,SEM,FT-IR,TGA and BET.The results were consistent with the literature reports.The microwave-assisted synthetic materials have slightly poorer crystallization properties,but always maintain a complete frame structure.Compared with the specific surface area and parti cle size,the specific surface area and pore volume of the microwave-assisted synthetic material are larger,the material is more uniform,the particle size is reduced,and thus the adsorption is different;and the amino-modified material is functionalized by its functional group.The introduction causes a decrease in the specific surface area and pore volume of the material,but the amino group and the tetracycline molecule can act,so that the adsorption performance is remarkably improved.At the same time,we conducted a kinetic study on the adsorption behavior of the materials.It was found that under the same conditions,the adsorption capacity of tetracycline by microwave-assisted synthetic materials was significantly better than that of conventional synthetic materials,and the adsorption amount of tetracycline by amino-modified materials also increased.The adsorption behaviors all satisfy the pseudo-second-order kinetic model.In order to understand the adsorption mechanism of tetracycline and the i sotherm and thermodynamics of the material adsorption tetracycline,it is found that the adsorption isotherm data of the prepared materials can better meet the Freundlich.The adsorption isotherm model belongs to the multi-molecular layer adsorption,and it is known from the thermodynamic data that the tetracycline adsorbed by the prepared material belongs to the spontaneous endothermic reaction.The pH influence adsorption experiment on the material showed that the surface potential of the microwave-assisted composite material decreased with the increase of pH value,and the adsorption amount increased under acidic conditions with the increase of pH value.Under the condition,the pH decreases and the adsorption amount reaches the maximum under the neutral condition.Comprehensive analysis,the main mechanism of the adsorption of tetracycline on the prepared materials is electrostatic interaction and?-?stacking.Finally,we centrifuged the material after adsorption of tetracycline,and regenerated it under ultrasound using water and methanol washing.After three repeated experiments,the adsorption amount was still high. |
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