Please Plan to Attend:

Date: Monday, March 18, 2024
Time: 9:30am
Location: Donovan Hall 1193

Title: Title:  Investigation and Mechanistic Understanding of Interactions between Micro/nano Plastics and Environmental Pollutants

Abstract:  Micro/nano plastics (MNPs) with a diameter of less than 5 millimeters have emerged as ubiquitous pollutants drawing widespread attention due to their harmful effects caused by not only their toxicity but also their interactions with a wide variety of environmental pollutants. However, a systematic, mechanistic, and profound understanding of the interaction of MNPs and environmental pollutants is yet to be attained. In this presentation, three research studies on the interaction of MNPs and environmental pollutants will be elaborated from the aspects of surface adsorption, mineral nucleation, and modeling predictions. Firstly, laboratory investigation of mercury on anaerobically aged MNPs were carried out to investigate the kinetics and thermodynamics of mercury adsorption onto MNPs. Instrumental characterizations reveal that the adsorption mechanisms include increment of surface area, electrostatic interaction, and surface functional groups. Secondly, nucleation of barium sulfate (barite) on the surface of MNPs was investigated in a systematic manner. The heterogenous nucleation process of barite on metal surfaces coated with real environmental MNPs and sample MNPs with different sizes and functional groups were in-situ and real-time monitored. The results showed that with larger size and surface charge of the MNPs, metal surface displayed a reduced potential to form scale and that surface with a more hydrophobic and negatively charged surface inhibited the process of heterogeneous nucleation. Thirdly, to better elucidate the sorption process of mechanisms and to predict the sorption capacity of MNPs on pollutants, a poly-parameter linear free-energy relationship based machine learning model was developed and tested with the experimental data. The results from feature analysis showed principal sorption mechanisms being hydrophobic partitioning, hydrogen bond formation, and π-π interaction. These studies reveal the mechanisms of the interaction between MNPs and environmental pollutants, provides state of art models for the predication of sorption behavior of MNPs on organic pollutants, and sheds light on heterogeneous nucleation of mineral crystals in the presence of MNPs.