Comparative Studies of Chitosan-Silver Nanocomposites from Commercial and Biowaste Sources

In this work, silver nanoparticles/chitosan nanocomposites were prepared for possible industrial and biomedical applications. Chemical reduction of silver nitrate salt produced silver nanoparticles (AgNPs). Low molecular weight chitosan (LMWCS) which connotes artificial chitosan (ArCS) was obtained, and biodegradable chitosan was extracted from snail shells using standard procedures. Sodium tripolyphosphate (TPP) was used to produce chitosan nanoparticles (snail shell nanochitosan (ScCSNPs) and artificial nanochitosan (ArCSNPs)) from extracted chitosan and LMWCS. AgNPs-CSNPs were produced by incorporating AgNPs into CSNPs as antimicrobial agents. Characterization of the chitosan doped silver nanoparticles was conducted using scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The morphological properties of nanochitosan (ScCSNPs and ArCSNPs) and AgNPs-nanochitosan (ScCSNPs-AgNPs and ArCSNPs-AgNPs) indicated porosity and agglomeration, while functional groups -OH, -NH, and C-H were revealed. The presence of AgNPs in the polymeric matrix of nanochitosan was confirmed by a shift in some of the adsorption bands. XRD and DSC results revealed that the nanochitosan is crystalline, and they also confirmed the presence of AgNPs in the chitosan polymeric matrix. The study established that chitosan extracted from snail shells, which contribute to environmental pollution, could be a good source for the preparation of nanocomposite materials, which are useful in a variety of industrial and biomedical applications.