Photochemical Reduction as a Green Method for the Synthesis and Size Control of Silver Nanoparticles in κ-Carrageenan

Abstract

An eco-friendly photochemical method for preparing silver nanoparticles (Ag-NPs) in a natural polymer (κ-carrageenan) was successfully developed and is reported in this study. The Ag-NPs have been synthesized via a photochemical method by using UV-irradiation, silver nitrate and κ-carrageenan as a reducing agent, a silver precursor and a stabilizer at room temperature, at different irradiation time. The formation of Ag-NPs was improved by UV–vis spectroscopy where surface plasmon absorption maxima was observed at 420–430 nm. Transmission electron microscopy (TEM) data and the size distribution were in an agreement with the finding from the UV–vis spectra. Scanning electron microscope data illuminated the changes in the surface of κ-carrageenan. Fourier transform infrared spectra indicated the interactions between Ag-NPs and κ-carrageenan. In addition, the Ag-NPs were characterized by X-ray diffraction (XRD). The peaks in the XRD pattern showed that the Ag-NPs possessed an FCC structure. The green methods by using an eco-friendly stabilizer and reducing agent provide green and economic attributes to this paper. These results demonstrate the successful synthesis of Ag-NPs in κ-carrageenan by using UV-irradiation as a green and a photochemical reducing method. Ag-NPs were obtained by using UV-irradiation at different times at room temperature, where increasing irradiation time corresponded to the formation of smaller more spherical Ag-NPs. The synthesized Ag-NPs find applications as bacteria inhibitors and can be applied in the medical field.