Preparation Of Ag Nanoparticles Modified Nanosheets SERS Substrates And Their Application In Detection Of Printing And Dyeing Wastewater

Printing and dye wastewater contains a variety of organic pollutants,such as highly toxic heavy metal ions,refractory additives and dye molecules,which have certain carcinogenic and teratogenic risks,and it will cause serious threats to human health and safety.Therefore,the realization of rapid detection of these pollutants is important for the protection of the ecological environment and human health.In recent years,the rapid development of non-destructive testing technology based on surface-enhanced Raman scattering（SERS）effect has provided an important way for the rapid and highly sensitive detection of printing and dyeing wastewater.The key to obtaining high-quality SERS signals is to prepare SERS substrates with good uniformity and high sensitivity.In this thesis,three substrates with high sensitivity and uniformity were prepared by a template-assisted method in combination with other nanomaterial fabrication techniques,and trace detection of pollutants such as dye molecules rhodamine 6G（R6G）and4-aminothiophenol（4-ATP）was realized.The main research contents and conclusions of this thesis are as follows:（1）Preparation of three-dimensional（3D）Ag@Au@Co（OH）₂ nanoflower array SERS substrates by self-reduction method and study of its detection performance for printing and dye wastewater.Firstly,large-scale nanoflower array films assembled by Co（OH）₂nanosheets were obtained by template-assisted-electrochemical deposition.Then a small amount of Au nanoparticles were sputtered on the surface of Co（OH）₂ nanoflower flims,and the Ag nanoparticles were modified by the redox reaction of Ag⁺and Co（OH）₂.Finally,Ag@Au@Co（OH）₂ nanoflower array substrates were obtained.The substrate has a uniform morphology and large specific surface area,which not only contributed to the adsorption of probe molecules,but also supported high density Ag nanoparticles on the surface of the nanoflower,thus forming high density SERS hot spots.Therefore,the substrate showed good SERS sensitivity and uniformity,and achieved low concentration detection of 10^-10 mol/L 4-ATP molecules with a relative standard deviation（RSD）of9.43%.（2）Preparation of 3D Ag@Co（OH）₂ nanoflower array SERS substrates by direct sputtering and study of its detection performance for printing and dye wastewater.The nanoflower array substrate assembled by Co（OH）₂ nanosheets was obtained in the same way as in the previous chapter,and then the Ag@Co（OH）₂ nanoflower array SERS substrate was directly obtained by combining ion sputtering method.The substrate exhibited good SERS sensitivity and uniformity,which realized the detection of low concentrations of 10^-11mol/L R6G and 10^-9 mol/L 4-ATP molecules with an RSD value of17.5%.In addition,the SERS substrate also achieved the detection of 10^-9 mol/L thiram,indicating that the substrate has a potential application prospect in the detection of agricultural residues in water.（3）Preparation of Ag@Zn-ZIF-L nanosheet array SERS substrate by chemical deposition and study of its detection performance for printing and dye wastewater.The ordered Zn-ZIF nanosheet arrays were obtained on the lager area micro-pit arrays films by chemical deposition method,and then the Ag@Zn-ZIF-L nanosheet array SERS substrate was further successfully synthesized by ion sputtering.The substrate has a high specific surface area,which can not only load high density Ag nanoparticles,but also has adsorption effect on probe molecules,showing good SERS activity and uniformity.Based on the SERS substrate,the detection of 10^-10 mol/L R6G was realized,and the RSD was12.21%,which is expected to be applied to the rapid detection of dyeing wastewater.