Radiation Induced Silver Nanoparticles in Ionically Crosslinked Alginate Beads for Efficient Catalytic Degradation of Basic Dye

Abstract

Silver nanoparticles (Ag NPs) are widely used as engineered nanomaterials in many advanced nanotechnologies, due to their versatile, easy and cheap preparations combined with peculiar chemical-physical properties. Their increased production and integration in environmental applications including water treatment raise concerns for their impact on humans and the environment. In this study, gamma radiation dose of 20 kGy was utilized to induce the synthesis silver nanoparticles (Ag NPs) in the alginate micro beads to prepare calcium Alginate/Ag (Ca-ALG/Ag) nanocomposite beads. These beads were then used to degrade toxic basic dyes in waste water. Initially, Ca-ALG /Ag nanocomposite beads were synthesized and characterized using Ultra Violet-visible spectrum (UV-Vis), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) for confirming the formation of Ag NPs and morphological study. The catalytic efficiency of the resulting Ca-ALG/Ag nanocomposite beads is evaluated for the degradation of dyes such sandocryl blue dye in the presence of NaBH4. The catalytic degradation of sandocryl blue dye was very fast in the present conditions: 0.1 g of catalyst 5 ml NaBH4 and the optimum time for complete reduction was 30 min. The pseudo-first order, pseudo second order and intra particle diffusion model used to evaluate the kinetic models and the mechanism of the degradation. Results showed that the degradation kinetics best fit the pseudo-second-order model and Langmuir isotherm model. The Biopolymer-based nanocomposite beads of calcium alginate, and Ag NPs can be applied to reduce dyestuff, where it is economically viable and environmentally friendly.