title: Synthesis of silver/montmorillonite nanocomposites using γ-irradiation.
abstract: Silver nanoparticles (Ag-NPs) were synthesized into the interlamellar space of montmorillonite (MMT) by using the γ-irradiation technique in the absence of any reducing agent or heat treatment. Silver nitrate and γ-irradiation were used as the silver precursor and physical reducing agent in MMT as a solid support. The MMT was suspended in the aqueous AgNO(3) solution, and after the absorption of silver ions, Ag(+) was reduced using the γ-irradiation technique. The properties of Ag/MMT nanocomposites and the diameters of Ag-NPs were studied as a function of γ-irradiation doses. The interlamellar space limited particle growth (d-spacing [d(s)] = 1.24-1.42 nm); powder X-ray diffraction and transmission electron microscopy (TEM) measurements showed the production of face-centered cubic Ag-NPs with a mean diameter of about 21.57-30.63 nm. Scanning electron microscopy images indicated that there were structure changes between the initial MMT and Ag/MMT nanocomposites under the increased doses of γ-irradiation. Furthermore, energy dispersive X-ray fluorescence spectra for the MMT and Ag/ MMT nanocomposites confirmed the presence of elemental compounds in MMT and Ag-NPs. The results from ultraviolet-visible spectroscopy and TEM demonstrated that increasing the γ-irradiation dose enhanced the concentration of Ag-NPs. In addition, the particle size of the Ag-NPs gradually increased from 1 to 20 kGy. When the γ-irradiation dose increased from 20 to 40 kGy, the particle diameters decreased suddenly as a result of the induced fragmentation of Ag-NPs. Thus, Fourier transform infrared spectroscopy suggested that the interactions between Ag-NPs with the surface of MMT were weak due to the presence of van der Waals interactions. The synthesized Ag/MMT suspension was found to be stable over a long period of time (ie, more than 3 months) without any sign of precipitation.
authors.affiliation: Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia. kamyarshameli@gmail.com
authors.forename: Kamyar
authors.initials: K
authors.lastname: Shameli
authors.forename: Mansor Bin
authors.initials: MB
authors.lastname: Ahmad
authors.forename: Wan Md Zin Wan
authors.initials: WM
authors.lastname: Yunus
authors.forename: Nor Azowa
authors.initials: NA
authors.lastname: Ibrahim
authors.forename: Yadollah
authors.initials: Y
authors.lastname: Gharayebi
authors.forename: Sajjad
authors.initials: S
authors.lastname: Sedaghat
mesh_terms: D001546:Bentonite / Q000737:chemistry* / Q000528:radiation effects; D004355:Drug Stability; D005720:Gamma Rays; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001546:Bentonite; D012834:Silver