Soda lignin from Citrus sinensis bagasse: extraction, NMR characterization and application in bio-based synthesis of silver nanoparticles

Lignin is one of the most abundant natural materials with many important roles, especially in providing structural resilience of plants. It is formed through the radical polymerization of aromatic monomers and shows structural and compositional differences depending on sources, biosynthesis and processes used for its extraction. Herein, we present extraction of lignin from the Citrus sinensis (sweet orange) bagasse using full sequential extraction in a yield of 0.34% and report on the soda lignin nuclear magnetic resonance (NMR) properties (¹H NMR and 2D NMR). The soda lignin was then applied in the sustainable synthesis of silver nanoparticles (AgNPs). The obtained silver nanoparticles showed unimodal distribution of sizes, spherical morphology, average diameters of 19.1 ± 4.7 nm and negative zeta potentials of − 28.5 ± 3.2 mV. The AgNPs were also found to be stable over several months.