Aggregation Behavior of Nanoplastics with Minerals: Distinctive Impacts of the Exposure Order to Natural Organic Matter

Presenter: Ben K. Feldman

Group Members: Emily K. Miller

Faculty Sponsor: Baoshan Xing

School: UMass Amherst

Research Area: Chemistry and Materials Science

Session: Poster Session 5, 3:15 PM - 4:00 PM, Auditorium, A52

ABSTRACT

Heteroaggregation with naturally occurring substances plays a critical role in determining the transport, fate, and ecotoxicity of nanoplastics. In this study, we investigated how different exposure sequences of nanoplastics and minerals to natural organic matter (NOM) affect their subsequent heteroaggregation. Our results indicate that when minerals are pre-exposed to NOM, the extent of heteroaggregation is significantly enhanced compared to scenarios where nanoplastics are pre-exposed to NOM. At low NOM concentrations, the modulation of heteroaggregation is primarily driven by electrostatic interactions, hydrogen bonding, and charge-assisted hydrogen bonding. In contrast, at high NOM levels, steric hindrance becomes the dominant mechanism controlling heteroaggregation. Moreover, the presence of Ca²⁺ was found to play a pivotal role, particularly under NOM-rich conditions, by facilitating aggregation through Ca-bridging effects.

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