Facile and Efficient Synthesis of Silver Nanoparticles Based on Biorefinery Wood Lignin and Its Application as the Optical Sensor

Abstract

Fabricating silver nanoparticles (AgNPs) based on renewable energy sources is wildly exploited because of the sustainable synthetic strategy and versatile applications of AgNPs. Alkali lignin (AL), as the byproduct from pulp mills, is a potential natural reducing agent. However, the synthetic methods of AL-based AgNPs (AL@Ag) still have drawbacks, such as unusual conditions and extra and high-cost purification processes. Here, a facile and efficient approach to synthesize and purify good-dispersing AL@Ag (17–27 nm) was presented, using Ag2O as the silver precursor and AL as both reducing agents and stabilizers in dimethyl sulfoxide (DMSO) solvent. The maximum reduction capacity of AL to Ag+ was increased to 8 mM/g at room temperature because of the activation of both Ag2O and DMSO. Most conveniently, the product was effectively purified by easy centrifugation. The reducing mechanism and reaction behavior were also systematically studied. Meanwhile, AL@Ag maintained versatile applications of AgNPs and exhibited great potential as the colorimetric sensor and plasmonic resonance energy acceptor for Hg2+ and rhodamine B, respectively. Our work displayed a general and efficient method to prepare AL@Ag, which might provide a realizable perspective to the high-value utilization of lignin.