Aging characteristics of degradable and non-biodegradable microplastics and their adsorption mechanism for sulfonamides

Lezu Shen; Yanhua Wang; Ruihan Liu; Yanni Yang; Yingnan Liu; Baoshan Xing

doi:10.1016/j.scitotenv.2023.166452

Aging characteristics of degradable and non-biodegradable microplastics and their adsorption mechanism for sulfonamides

Sci Total Environ. 2023 Nov 25:901:166452. doi: 10.1016/j.scitotenv.2023.166452. Epub 2023 Aug 20.

Authors

Lezu Shen¹, Yanhua Wang², Ruihan Liu¹, Yanni Yang¹, Yingnan Liu¹, Baoshan Xing³

Affiliations

¹ School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China.
² School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China. Electronic address: yhwang930@foxmail.com.
³ Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, United States. Electronic address: bx@umass.edu.

PMID: 37607636
DOI: 10.1016/j.scitotenv.2023.166452

Abstract

As emerging pollutants, microplastics (MPs) and antibiotics (ATs) became a research hotspot in recent years. To evaluate the carrier effect of degradable and non-biodegradable MPs in the aquatic environment, the adsorption behaviors of polyamide (PA) and polylactic acid (PLA) towards two sulfonamide antibiotics (SAs) were investigated. Both chemical and photo-aging were used to handle the virgin MPs. Compared with PA, PLA was aged more drastically, showing the obvious grooves, notches and folds. However, due to the higher temperature during chemical aging, the tiny KPLA (PLA aged by K₂S₂O₈) particles were agglomerated and the specific surface area was reduced to nearly 95 %. For PA, the oxidation of chemical aging was stronger than photo-aging. After aging, the hydrophilicity and polarity of MPs increased. In the adsorption experiments, the adsorption capacity of PA towards SAs was 1.7 times higher than that of PLA. Aging process enabled the adsorption capacity of PLA increased 1.22-3.18 times. Overall, the adsorption capacity of sulfamethoxazole (SMX) by both MPs was superior to sulfamerazine (SMR). These results would help to understand the carrier effects and potential ecological risks of MPs towards co-existing contaminants.

Keywords: Adsorption mechanism; Aging; Degradable microplastics; Microplastics; Sulfonamide antibiotics.