Microplastics (MPs) have been recognized as a global concern due to their potential health effect, as MPs could adsorb and carry various pollutants in aquatic environment. In the present study, a new environmental behavior related to polyvinyl chloride microplastics (PVC-MPs) and the underlying mechanism were described. Our results showed that the photo-aged PVC-MPs could affect the transformation of cephalosporin antibiotics. For instance, the presence of altered PVC-MPs significantly accelerated the hydrolysis of cefazolin (CFZ), but exhibited negligible effect on the degradation of cephalexin (CFX). As indicated by in situ Fourier transform infrared spectra and theoretical calculations, hydrogen bonds could be formed between β-lactam carbonyl of CFZ and the oxygen-containing moieties on the aged PVC-MP surfaces. The hydrogen-bonding was able to significantly increase the positive atomic Mulliken charge on the β-lactam carbonyl carbon, thus narrowing the energy gap of CFZ hydrolysis and subsequently enhancing the disruption of β-lactam ring. While for CFX, instead of the β-lactam carbonyl, the amide amino group was involved in the hydrogen-bonding due to the structural difference. Therefore, in addition to increasing the adsorption capacity, the aged PVC-MPs could act as the catalyst to mediate the transformation of antibiotics. Our study would help improve the understanding for interactions between contaminants and MPs in natural environments.
Bibliographical noteFunding Information:
This work was financially supported by National Natural Science Foundation of China ( 21906079 and 22176092 ), Fundamental Research Funds for the Central Universities ( 0211/14380174 ), Excellent Research Program of Nanjing University (ZYJH005) and International Institute for Environmental Studies. We thank the Analytical Center and High Performance Computing Center of Nanjing University for the characterization of samples and computational study.
© 2021 Elsevier Ltd
- Cephalosporin antibiotics
- Hydrogen-bonding interaction
- Polyvinyl chloride microplastics
ASJC Scopus subject areas
- Environmental Engineering
- Civil and Structural Engineering
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal