Green synthesis of AgNPs using lignocellulose nanofibrils as a reducing and supporting agent

Abstract

A novel green approach was developed for producing silver nanoparticles (AgNPs) using lignocellulose nanofibrils (LCNF). This method does not require any additional reducing agent, and the LCNF itself serves both as a reducing agent and a supporting material. A simple autoclave procedure was employed for the synthesis. The synthetic conditions such as concentrations of reactants and reaction time were optimized. Also, the effect of lignin content in LCNF on the formation of AgNPs was evaluated. Three types of cellulose nanofibrils, i.e., HCNF (0% lignin), LCNF-5 (5% lignin), and LCNF-18 (18% lignin), were employed for the preparation of AgNPs. Three types of AgNPs were obtained and thoroughly characterized using UV-vis, Fourier-transform Infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results suggest that LCNF can be employed as a green source for the reduction and effective stabilization of AgNPs, but an increased content of lignin can have an adverse effect on the yield of AgNPs. However, the presence of lignin greatly influenced the particle size. Therefore, LCNF with small amounts of lignin (5%) is best for producing AgNPs.