Nanoplastic adsorption characteristics of bisphenol A: The roles of pH, metal ions, and suspended sediments

Nanoplastics (NPs) are widely found in the environment and can act as a vector for various toxic substances and promote their diffusion and bioenrichment, but the underlying mechanisms are largely unknown. Here, the adsorption characteristics of bisphenol A (BPA) onto NPs were explored. The results show that the adsorption of BPA on NPs was dominated by saturated single-layer adsorption and affected by both intra-particle diffusion and liquid film diffusion. Electrostatic interaction, π-π interaction, and hydrophobic effects played key roles in adsorption. In addition, the introduction of electrolytes inhibited the adsorption of BPA onto NPs. Interestingly, the introduction of suspended sediment promoted the formation of heterogeneous aggregates of NPs-SS, thereby reducing the adsorption capacity, indicating that aggregation may play an important role in the adsorption behavior of NPs. Overall, our results provide new insights into the adsorption behavior of BPA on NPs and the underlying mechanisms under different environmental conditions.