Differential Photoaging Effects on Colored Nanoplastics in Aquatic Environments: Physicochemical Properties and Aggregation Kinetics.
Environ Sci Technol
; 57(41): 15656-15666, 2023 Oct 17.
Article
en En
| MEDLINE
| ID: mdl-37747788
ABSTRACT
Nanoplastics (NPs) have different colors, which could affect their photoaging processes in aquatic environments. This study investigated the effects of irradiation on physicochemical properties and aggregation kinetics of five colored NPs. Photodegradation rates and photooxidation degrees ranked white ≈ yellow > red > blue ≈ black NPs, indicating that NPs with longer color wavelengths photoaged faster. The discoloration process followed color fading (2-14 days, except for white NPs), yellowing (10-16 days), yellow fading (18 days), and turning transparent (20-22 days). White NPs exhibited a different photoaging sequence (C-H â C-OH â CâO â O-CâO) from others. Photodegradation was mainly controlled by singlet oxygen, producing 13 chemicals that were mostly organic acids. The overall colloidal stability of pristine NPs ranked blue > yellow > red > black > white. Irradiation for 16 days retarded aggregation of white and other NPs in NaCl solution, raising the critical coagulation concentration (CCC) by 82.14 and 0.85-7.90%, respectively. Contrarily, irradiation promoted aggregation in CaCl2 solution by reducing the CCC of white (67.37%) and other (33.33-37.58%) NPs. The findings demonstrate that colored NPs underwent photoaging processes different from white/transparent NPs, which were focused by previous work, highlighting the important role of color in their environmental fate and transport.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Environ Sci Technol
Año:
2023
Tipo del documento:
Article
País de afiliación:
China