激进的
化学
环境化学
缺氧水域
污水污泥
微塑料
氧化还原
非生物成分
活性污泥
环境工程
污水处理
有机化学
环境科学
生物
古生物学
作者
Ruizhi Xing,Zewei Chen,Hanyue Sun,Hanpeng Liao,Shuping Qin,Weizhen Liu,Yan Zhang,Raymond J. Zeng
标识
DOI:10.1016/j.jhazmat.2022.128405
摘要
Composting is the last "barrier" for microplastics (MPs) in the entry of organic solid wastes into the environment. The transformation of MPs is thought to be mainly driven by microorganisms during composting, whereas the contribution of abiotic processes that involve free radicals is often overlooked. Herein, we provide initial evidence for the generation of free radicals during sludge composting, including environmental persistent free radicals and reactive oxygen species, which accelerate the oxidative degradation of MPs. The ·OH yield of composting fluctuated greatly from 23.03 to 277.18 μmol/kg during composting, which was closely related to the dynamic changes in Fe(II) (R2 = 0.926). Analyses of the composted MPs physicochemical properties indicated that MPs were aged gradually with molecular weights decrease from 18% to 27% and carbonyl index value increase from 0.23 to 0.52. Further investigation suggested that the microbially-mediated redox transformation of iron oxides could occur on the MPs surface accompanied by the production of abundant free radicals, thereby leading to the damage of MPs during composting. These results reveal the critical role of free radicals in MPs ageing under oxic/anoxic alternation conditions of composting and provide new insights into the bio-chemical mechanism of contaminant removal or transformation during sludge composting.
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