| Title | Sulfide induces physical damages and chemical transformation of microplastics via radical oxidation and sulfide addition |
| Authors | Zhao, Mengting Zhang, Tong Yang, Xinlin Liu, Xinlei Zhu, Dongqiang Chen, Wei |
| Affiliation | Nankai Univ, Coll Environm Sci & Engn, Key Lab Pollut Proc & Environm Criteria, Minist Educ,Tianjin Key Lab Environm Remediat & P, Tianjin 300350, Peoples R China Nankai Univ, Inst Polymer Chem, Minist Educ, Coll Chem,Key Lab Funct Polymer Mat, Tianjin 300071, Peoples R China Peking Univ, Sch Urban & Environm Sci, Beijing 100871, Peoples R China |
| Keywords | GRAPHENE OXIDE WASTE-WATER AQUEOUS SULFIDE IDENTIFICATION NANOPARTICLES PRODUCTS KINETICS FATE |
| Issue Date | 1-Jun-2021 |
| Publisher | WATER RESEARCH |
| Abstract | Transformation of microplastics in aquatic environments and engineered systems (e.g., wastewater treatment plants) significantly affects their transport, fate and effects. Here, we present the counterintuitive finding that sulfide, a prevalent nucleophile and reductant, can result in oxidation of microplastics, in addition to sulfide addition. Treating four model microplastics (thermoplastic polyurethane, polystyrene, polyethylene terephthalate and polyethylene) with 0.1 mM sulfide in a Tris-buffer solution (pH 7.2, 25 degrees C) resulted in physical damages (embrittlement and cracking) and chemical transformation (increased O/C ratio and formation of C-S bonds) of the materials. Pre-aging of the microplastics with O-3 or UV treatment had varied effects on their reactivities toward sulfide, depending on the specific structural and surface chemistry properties of the polymers. Electron paramagnetic resonance and radical trapping/quenching experiments showed that sulfide underwent spontaneous oxidation to form center dot OH radicals, which acted as the primary oxidant to attack the carbon atoms in the polymer chains, leading to surface oxidation and chain scission. Notably, sulfide addition, verified with X-ray photoelectron spectroscopy and 13C-nuclear magnetic resonance spectroscopy analyses, likely contributed to the physicochemical transformation of microplastics together with radical oxidation in a synergistic manner. The findings unravel an important transformation route (and a potential source) of microplastics in the environment. (C) 2021 Elsevier Ltd. All rights reserved. |
| URI | http://hdl.handle.net/20.500.11897/612603 |
| ISSN | 0043-1354 |
| DOI | 10.1016/j.watres.2021.117100 |
| Indexed | SCI(E) |
| Appears in Collections: | 城市与环境学院 |
