Abstract
This study examined the effects of ozonation and UV applied in series (O3+UV) or simultaneously (UVO) under four different ozone dosages from 4 to 7 mg/min to understand the surface alterations on polyethylene microplastics in aquatic environments via the photochemical oxidation process. The plastic samples were analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. FTIR spectroscopy showed that the levels of carbonyl (ketone and esters) and vinyl groups increased gradually with increasing ozone dose injected; the highest was observed at 6 mg/min of ozone. On the other hand, the levels at 7 mg/min of ozone were slightly lower than those at 4 to 6 mg/min. This could be related to the deeper penetration into the crystalline bulk polymeric chain. The contact angle changed from 125.90˚ to the lowest value of 120.04˚ and 123.8˚ for O3+UV and UVO, respectively. Furthermore, XPS showed that C-O was only presented in the 7 mg/min sample, whereas C-O, OH, C=O, and C-C=O remained for 4 to 6 mg/min. Overall, O3+UV can oxidize the surface of the polyethylene microplastic particles more effectively than those of UVO, irrespective of the ozone dosages.
Original language | English |
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Article number | 210028 |
Journal | Environmental Engineering Research |
Volume | 27 |
Issue number | 3 |
DOIs | |
State | Published - Jun 2022 |
Bibliographical note
Publisher Copyright:© 2022 Korean Society of Environmental Engineers.
Keywords
- Carbon-oxygen functionalities
- Contact angle
- FTIR
- Microplastics
- X-ray photoelectron spectroscopy (XPS)