Work

Chemical process-induced microplastic aging and its impact on coagulation-flocculation efficiency

Year: 2026

Type: article

Abstract: Coagulation is widely used to remove microplastics (MPs) from aquatic systems, yet its effectiveness for aged particles remains poorly understood. This study investigates how chemical, thermal, and physical aging alter polyethylene (PE) MPs and affect their removal during coagulation. The PE particles were subjected to chemical aging (HCl, NaOH, CH 3 OH, H 2 O 2 , KMnO 4 , Na 2 S 2 O 8 ), thermal aging (5, 25, 60 °C), and physical treatments (UV irradiation, ozonation, Fenton process, ultrasound) under varying pH conditions (3–11). Aging strongly influenced coagulation performance: efficiencies increased markedly for MPs aged in HCl, NaOH, KMnO 4 , and Na 2 S 2 O 8 , with KMnO 4 -treated particles achieving the highest removal (79%), while methanol and H 2 O 2 had neutral or inhibitory effects. SEM and LDIR imaging revealed morphological changes, including increased surface roughness, cracks, and reduced particle size. FTIR spectroscopy showed chemical modifications such as formation of carbonyl, hydroxyl, and C–O group formation, particularly after oxidative treatments such as ozonation. These structural and chemical changes enhanced particle reactivity, aggregation, and flocculation during coagulation. Multivariate analyses (PCA and Pearson correlation) demonstrated strong interdependencies between aging conditions, particle properties, and removal efficiency. In general, the results highlight that aging significantly modifies the physicochemical characteristics of MPs, increasing their reactivity and altering their behavior during water treatment. These findings emphasize the importance of evaluating coagulation and other removal technologies using aged microplastics to accurately assess treatment efficiency. and environmental risks. • Microplastic aging strongly influences removal efficiency during coagulation. • Oxidative aging (KMnO 4 , Na 2 S 2 O 8 ) increased PE removal up to 79%. • Surface oxidation and fragmentation enhanced microplastic flocculation. • Ozonation and UV improved removal, while ultrasound reduced efficiency. • Pristine microplastics underestimate real coagulation performance.

Source: Water Resources and Industry

DOI: 10.1016/j.wri.2026.100354

Authors: Sabina Ziembowicz, Małgorzata Kida, Mateusz Baluk, Piotr Koszelnik

Institutions: Rzeszów University of Technology, University of Gdańsk

Language: English

Topic: Microplastics and Plastic Pollution

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDGs: Responsible consumption and production, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $3,613