Electrolyte‐Dependent Stability of Sulfonated Lignin Phenolic Resin Nanoplastics in Aquatic Systems: e‐DLVO Theory and Molecular Modeling

Plastic waste is widely recognized as a global environmental threat. Nanoplastics (NPs), derived from the degradation of macroplastics and microplastics, pose potential risks to human health. The aggregation behavior of NPs in aquatic systems is primarily governed by electrolyte concentration and pH. In this study, the aggregation behavior of NPs, represented by sulfonated lignin phenolic resin (SLPFR), was systematically investigated in aqueous solutions containing a series of monovalent and divalent electrolytes. Aggregation kinetics experiments, adsorption studies, material characterization, and extended‐Derjaguin–Landau–Verwey–Overbeek (e‐DLVO) theoretical calculations demonstrated that electrostatic interaction is the dominant force governing the aggregation of SLPFR NPs. Different electrolyte types alter the surface charge of NPs, consequently increasing the electrostatic repulsion and steric hindrance between particles. These findings provide significant insights for better assessing the aggregation of NPs in diverse aquatic environments and their associated environmental impacts and risks.