One-Pot Synthesis and Characterization of Gold Nanoparticle-Embedded Natural Magnetic Particles/Chitosan Composite

This research synthesized natural magnetic particles/chitosan/gold nanoparticles composites (NMP/Chi/AuNPs) using a green method. AuNPs were synthesized using chitosan as a reducing agent and stabilizer in one step. The obtained AuNPs were characterized using UV-Vis spectrophotometer and TEM. Results showed that AuNPs were spherical with an average of 14.9 nm and absorbed at visible light (~530 nm). Then, AuNPs were impregnated on NMP/Chi at room temperature. The impregnation results were characterized using FTIR, XRD, and TEM. In the IR spectra of NMP/Chi and NMP/Chi/AuNPs, the NH bending vibrations of NH2 are shown at 1604 and 1631 cm-1. The NMP/Chi/AuNP showed a decrease in intensity and the peak shift to 1395 cm-1, stretching vibration of C-O from primary alcohol group. Fe-O vibrations of Fe3O4 in NMP/Chi and NMP/Chi/AuNPs are shown at 566 and 583 cm-1. The intensity peak shift and decrease indicate an interaction between AuNPs and NMP/Chi. The results of the XRD NMP/Chi/AuNPs characterization showed that the diffraction peak at 2Ө 35.44° decreased in intensity, resulting in a decrease in crystallinity caused by impregnated AuNPs and the destruction of hydrogen bonds. The new diffraction peak at 2Ө 38.24° indicates the presence of AuNPs. TEM analysis showed an amorphous layer around the NMP, and the average size of AuNP in the NMP/Chi/AuNP composite was 23.01 nm.