Extraction of lignin from corncob residue via a deep eutectic solvent for the preparation of nanoparticles by self-assembly

Reducing the structural heterogeneity of lignin and simultaneously improving the effective utilization of corncob residue is vitally important for biorefinery processing. In this study, lignin was extracted using a choline chloride/lactic acid-based deep eutectic solvent (DES) for the preparation of lignin nanoparticles (LNPs) by self-assembly. Nuclear magnetic resonance (NMR), fourier transform infra-red (FT-IR), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) results showed that the extracted lignin exhibited different structural characteristics. In addition, the efficient pretreatment facilitated the isolation of lignin fractions from corncob residue, with yields and purities of up to 85.6% and 97.8%, respectively. Furthermore, the LNPs were characterized by a hydrodynamic diameter of 48.66 nm, polydispersity index below 0.2 and zeta potential values exceeding −42.2 mV. By investigating the impact of the DES pretreatment conditions on the corresponding LNP properties, the current study lays the groundwork for the further development and optimization of lignin recovery technology.