Study On Detection Of Mercury Ion In Water And Adsorption Of Sulfadiazine By Functional Modified Cellulose

In this paper,using cellulose as a carrier,nitrogen-doped carbon quantum dots were loaded onto oxidized cellulose via?-glycidyloxypropyltrimethoxysilane?silane coupling agent KH-560?to prepare cellulose/nitrogen-doped carbon quantum dot composites,and used to detect mercury ions?II?.Cellulose was modified with metal-organic framework?Ui O-66?to prepare cellulose/Ui O-66 composite material for adsorption of sulfonamide antibiotics.In this reseach,sulfapyrazine,an organic pollutant in water,is used as an adsorption object,and functionalized cellulose is used for the adsorption research of sulfapyrazine,and it is expected to solve the problem of increasingly serious organic pollution in water.Using cotton?the main component is cellulose?as a carrier,first oxidize the C6hydroxyl group in cellulose by TEMPO?2,2,6,6-tetramethylpyridine-1-oxyl radical?/Na Br/Na Cl O oxidation system to increase the reactivity of hydroxyl groups.Then,the synthesized nitrogen-doped carbon quantum dots are supported on cellulose by the silane coupling agent KH-560.According to the different amount of loaded carbon quantum dots,three kinds of cellulose/nitrogen-doped carbon quantum dot composite materials?CKHC-5,CKHC-10 and CKHC-20?with different carbon quantum dot loadings were prepared.The cellulose/nitrogen-doped carbon quantum dot composite material?CKHC?is yellow under natural light,and emits strong blue fluorescence under the irradiation of 360 nm ultraviolet light.The fluorescence intensity is affected by the excitation light wavelength and p H,while the ionic strength has little effect on its fluorescence intensity.The composite material is used the detection limit of Hg²⁺can reach 3n M.When detecting low concentration?0-50n M?of Hg²⁺,the fluorescence intensity of the composite material shows a good linear relationship between the fluorescence intensity and Hg²⁺concentration,the unknown concentration of Hg²⁺can be detected.In the repeatability test,the repeatability of the composite material performed well.In addition,the principle of fluorescence quenching of composite materials by Hg²⁺was also explored.The composite material enables carbon quantum dots to be recycled and reused.Dissolved zirconium tetrachloride and terephthalic acid in N,N-dimethylformamide,add an appropriate amount of glacial acetic acid and cotton,and finally put them in a kettle to react at 90?for 24 hours.According to the different amount of Ui O-66 loaded,three kinds of cellulose/Ui O-66 composite materials,CU-1,CU-2 and CU-3,were prepared.The composite material can adsorb sulfapyrazine,and the maximum adsorption capacity of CU-1,CU-2 and CU-3 is86.44 mg/g,93.41 mg/g and 118.29 mg/g,respectively.After studying the adsorption process,it was found that the adsorption process conforms to the second-order kinetic adsorption model,and the isotherm adsorption line shows that it conforms to the Langmuir model.Soaking the used composite material with 0.01M sodium hydroxide solution can realize the regeneration and reuse of the material.After three consecutive regenerations,the adsorption of the composite material can be maintained at 65%.The composite material enables Ui O-66 to be reused and simplifies the recycling process of Ui O-66.