Preparation And Application Of Functional Cellulose-supported Metal Nanomaterials

Metal nanoparticles are widely used in environmental remediation,but their easy agglomeration and poor stability lead to problems such as reduction of reactive sites and secondary pollution,which limit their practical applications.In view of these drawbacks,this study proposed a strategy of"functionalized CNC-in situ synthesis of metal nanoparticles"based on the biodegradability and surface modifiability of nanocellulose.Two functionalized CNC-supported silver（CNC-EDTA@Ag NPs）/zero-valentiron（CNC-PDA@nZVI）nanocomposites were constructed.The Ag NPs/nZVI were uniformly dispersed on the surface of the support material,aiming to improve the antibacterial,catalytic and arsenic removal properties.And characterization methods were employed to study the mechanisms of the studied nanocomposite performance.The main research contents are as follows:（1）CNC was used as the base material,and it was functionalized with EDTAD.The introduction of effective functional groups such as amino and carboxyl groups on its surface enhanced the chelation and adsorption of Ag⁺,Ag NPs were in situ supported on the surface of CNC-EDTA,resulting in CNC-EDTA@Ag NPs.The efficient catalytic performance and broad-spectrum antibacterial properties of dendritic CNC-EDTA@Ag NPs were verified by characterizations and performance testing.The catalytic degradation experiments of the organic pollutant4-nitrophenol showed that the reaction rate of CNC-EDTA@Ag NPs was3.6 times higher than that of free Ag NPs.Meanwhile,the minimum inhibitory concentration of CNC-EDTA@Ag NPs against Escherichia coli was 2μg/m L,and the minimum inhibitory concentration against Bacillus subtilis was 4μg/m L,the plate coating experiments on Escherichia coli and Bacillus subtilis also showed that their antibacterial activity was 4times higher than that of free Ag NPs.In addition,it was found that the reason for the improvement of the antibacterial properties of CNC-EDTA@Ag NPs was that CNC-EDTA made Ag NPs well and uniformly dispersed,which has a long-lasting effect on cells,blocking bacterial activity,which can quickly and effectively kill bacteria.（2）CNC was used as substrate materials and functionalized with PDA.The introduction of effective functional groups such as imine/amine on its surface enhanced the chelating adsorption of Fe²⁺.nZVI was in situ loaded on the surface of CNC-PDA,and CNC-PDA@nZVI was prepared.Through the batch experiments,the dendritic CNC-PDA@nZVI with high arsenic removal performance was verified.The effects of p H,temperature,coexisting ions,and cyclic regeneration on the removal of As（III）/As（V）by CNC-PDA@nZVI were investigated.The adsorption capacity of CNC-PDA@nZVI was found to be 300.81 mg/g for As（III）and 297.40 mg/g for As（V）.The removal efficiency of CNC-PDA@nZVI was more than ten times higher than CNC and CNC-PDA.It was found that the enhanced As（III）/As（V）removal performance of CNC-PDA@nZVI was due to the uniform dispersion of nZVI by CNC-PDA and the large specific surface area of CNC-PDA,which provided a large number of adsorption sites.CNC-PDA@nZVIremovedAs（III）/As（V）through adsorption-oxidation-precipitation and coordination complexation.