Research progress on the preparation and application of lignin-based Pickering emulsions: A review

Lignin is a natural amphiphilic polymer material with properties such as being rich in raw materials, renewable, non-toxic, degradable, biocompatible, antioxidant, and UV-absorbing. It has a very broad application prospect. However, the heterogeneity and limited reactivity of lignin are the main obstacles to developing its potential value, which renders lignin an underutilized biomass resource. Pickering emulsions are emulsions stabilized by microparticles or nanoparticles, offering superior stability and reduced irritation. These benefits of Pickering emulsions make them very attractive. Pickering emulsions prepared using lignin particles leverage the advantages of lignin and Pickering emulsions, offering an effective approach to maximize the value of lignin and environmentally friendly preparation of Pickering emulsions. While there are many articles that have successfully prepared various types of lignin-based Pickering emulsions, comprehensive reports on them are scarce. This paper reviews recent research on various types of lignin-based Pickering emulsions. The applications and potential economic benefits of these lignin-based Pickering emulsions are also summarized. Finally, the prospects for future research on lignin-based Pickering emulsions are highlighted. It is hoped that this review could provide insights for the future development of lignin-based Pickering emulsions.