Biosynthesis of silver nanoparticles using chitosan immobilized Bacillus cereus: nanocatalytic studies

Abstract

In this paper, the biosynthesis study of silver nanoparticles (AgNPs) using chitosan immobilized on the Bacillus cereus (Bc-C) was performed via bioreduction without any reducing agent. Transmission electron microscopy (TEM) showed that the AgNPs were formed as uniformly sized and shaped in the range of 10–30nm. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction patterns (XRD) confirmed the formation of the Bc-C-Ag. XRD diffraction patterns revealed that the Ag+ on the Bc-C was reduced to Ag (0). This situation shows successful AgNPs synthesis using Bc-C. In the bioreduction studies, the effects of operating variables such as initial metal concentration, pH and contact time were also investigated. The AgNPs formed on Bc-C (Bc-C-Ag) were used as a bionanocatalyst for the reduction of 4-nitrophenol (4-NP). The kinetic models and the thermodynamic parameters were investigated to reveal the reduction mechanism.