Study On The Adsorption Behavior Of Gold Nanoparticles For Ag⁺ And Hg²⁺

With the development of nanomaterials,the research on the application of gold nanoparticles to the detection of environmental pollutants?metal ions,organics?is becoming more and more extensive,but the binding mechanism between gold nanoparticles and pollutants is unclear,such as whether the metal ion is ionic or simple form adsorption on the surface of gold nanoparticles,the amount and time of adsorption of metal ions,the shape of gold nanoparticles after adsorption of metal ions,and so on.In view of the controversy of the binding mechanism between Ag⁺and gold nanoparticles,and Hg²⁺as one of strong toxicity metal,this paper uses X-ray photoelectron spectroscopy?XPS?,UV-Vis spectroscopy,polarization resonance synchronous spectroscopy?PRS2?,and inductively coupled plasma mass spectrometry?ICP-MS?,Zeta potential titration,p H measurement and surface enhanced Raman spectroscopy?SERS?to study the adsorption behavior of metal ions such as Ag⁺and Hg²⁺on gold nanoparticles.The UV-Vis spectrum with the different particle size of the gold nanoparticles?13,30,50 nm?shows that the surface plasmon resonance of the gold nanoparticles after Ag⁺adsorption changed,and the gold nanoparticles at 13 nm changed the most.The depolarization spectrum obtained by PRS2 shows that the gold nanoparticles after Ag⁺adsorption remain spherical.Time-varying UV-Vis spectrum measurement shows that the adsorption of Ag⁺on the surface of gold nanoparticles consists of a fast and a slow parallel process.The adsorption time are 16?±2?s and 1000?±35?s,respectively.The adsorption constant is about 4×10⁶ L/mol,and the saturated bulk density is about4.7 nmol/cm².The results show that the fast process corresponds to the charge neutralization reaction and the slow process corresponds to the proton generation reaction,and silver is spontaneously adsorbed on the surface of the gold nanoparticles in the ionic state?Ag⁺?.The SERS results of Ag⁺adsorbed butylmercaptan?Bu T?functionalized gold nanoparticles shows that the Bu T-Ag complex on the gold nanoparticles is mobile,indicating that Ag⁺adsorption changed the gold nanoparticle surface ligands?Bu T?structure and function.XPS measurement results show that Hg²⁺is spontaneously adsorbed on the surface of gold?high-purity gold foil,sputtered gold-plated film,citrate-reduced gold nanoparticles,and Na BH₄-reduced gold nanoparticles?.Comparing the UV-Vis spectra of different particle sizes of gold nanoparticles?13,30,50 nm?,the surface plasmon resonance of the gold nanoparticles after Hg²⁺adsorption also changed,and the change of gold nanoparticles at 13 nm is also the most heavy.The results show that the mercury is also spontaneously adsorbed on the surface of gold nanoparticles in the ionic state(Hg²⁺),and the gold nanoparticles after Hg²⁺adsorption remains spherical.The adsorption of Hg²⁺on the surface of gold nanoparticles is also composed of a fast and a slow parallel process.The adsorption times are 326?±2?s and 4626?±37?s,respectively.The adsorption constant is 6.7×10⁶ L/mol,and the saturated bulk density is about 46 nmol/cm².The fast process corresponds to the charge neutralization reaction,and the slow process corresponds to the proton generation reaction.The SERS results of gold nanoparticles functionalized with ethanethiol?ET?,propylthiol?Pr T?,and butanethiol?Bu T?adsorbed by Hg²⁺show that ET-Hg,Pr T-Hg,Bu T-Hg is mobile,indicating that Hg²⁺adsorption also changes the structure and function of the ligands on the surface of gold nanoparticles.The same experimental method for detecting Ag⁺and Hg²⁺was used to determine the adsorption of other metal ions and hexane on the surface of gold nanoparticles to test the universality of this method.First,the XPS technology is used to verify whether the adsorption of metal ions on gold spontaneously.Then the depolarized polarization spectrum obtained by PRS2 was used to verify whether the gold nanoparticles adsorbed by Pb²⁺and hexane remained spherical.This work not only has new insights into the combination of metal ions such as Ag⁺,Hg²⁺,and organic matter hexane with gold nanoparticles,but also is important for exploring the combination of other metal ions with gold nanoparticles.And it can be used to explore a wide range of nanometers.The particle interface interaction has laid a theoretical foundation for the development of new methods for detecting and treating metal ion pollutants in water.