Preparation of Lignin-Based Nanoparticles with Excellent Acidic Tolerance as Stabilizer for Pickering Emulsion

In this work, novel lignin-based nanoparticles (LβNPs) with high acidic tolerance were successfully prepared via electrostatic interaction between β-alanine and lignin nanoparticles. The effects of the mass ratio of lignin nanoparticles to β-alanine and pH value on the morphology and particle sizes of LβNPs were investigated with the aim of obtaining the ideal nanoparticles. The optimized LβNPs were spherical in shape with an average particle size of 41.1 ± 14.5 nm and exhibited outstanding structure stability under high acidic conditions (pH < 4). Subsequently, Pickering emulsions stabilized by LβNPs were prepared using olive oil as the oil phase. Additionally, the effects of pH value, droplet size, morphology, and storage stability on Pickering emulsions were also analyzed. The emulsions displayed excellent stability, and were stable against strongly acidic conditions (pH < 4) after 30 days of storage. The study presented a promising approach to preparing lignin-based nanoparticles with high acidic tolerance (an ideal type of stabilizer to prepare emulsions), and exhibited extremely high potential application values in the fields of drug delivery, food additives, and oily wastewater treatment.