We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Molecular-level insight into the behavior of metal cations and organic matter during the aggregation of polystyrene nanoplastics
Summary
Researchers used molecular dynamics simulations and experiments to show that organic matter and metal cations play competing roles in polystyrene nanoplastic aggregation — with bisphenol A displacing humic acid, and calcium more effective than magnesium at destabilizing particles despite magnesium's stronger binding to surface functional groups.
In this study, the behavior of metal cations and organic matter during polystyrene nanoplastics (PSNP) aggregation was explored combing experimental measurements and molecular dynamics simulation. The results indicated that coexisting organic matter, including organic pollutants and humic acid (HA), play a complex role in determining PSNP aggregation. The representative organic pollutant, bisphenol A, exhibited competitive behavior with HA during heteroaggregation, and the heteroaggregation between HA and PSNP was impaired by bisphenol A. The bridging effect of metal ions in aggregation is related to their interaction strength with functional groups, binding affinity with water molecules, and concentration. In particular, Mg interacts more strongly with oxygen-containing functional groups on PSNP than Ca. However, Mg is more favorable for binding with water and is therefore not as effective as Ca for destabilizing PSNP. Compared with Ca and Mg, Na showed a weaker association with PSNP; however, it still showed a significant effect in determining the aggregation behavior of PSNP owing to its high concentration in seawater. Overall, we provided a molecular-level understanding of PSNP aggregation and deepened our understanding of the fate of nanoplastics.