Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China.
Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Hazard Mater. 2024 Sep 15;477:135262. doi: 10.1016/j.jhazmat.2024.135262. Epub 2024 Jul 20.
Biodegradable plastics, as an alternative to petroleum plastics, are fiercely increasing, but their incomplete degradation under natural conditions may lead to the breakdown into microplastics (MPs). Here, we explored the impacts of chicken manure-derived (MBC) and wood waste-derived biochar (WBC) on the degradation of polylactic acid microplastics (PLA-MPs) during soil incubation for one year. Both biochars induced more pronounced degradation characteristics in PLA-MPs, including enhanced surface roughness, the proportion of MPs < 100 µm by 12.89 %-25.67 %, oxygen loading and O/C ratio to 71.74 %-75.87 % and 1.70-1.76, as well as accelerated carbon loss and the cleavage of ester group and C-C bond. Also, biochar increased soil pH, depleted inorganic nitrogen and available phosphorus, and changed enzymic activity in PLA-MP-polluted soils. We proposed that both biochars accelerated the PLA-MP degradation by inducing alkaline, aminolysis/ammonolysis, oxidative, and microbial degradation. Among these, MBC induced aminolysis/ammonolysis by NH via Fedriven NO/NO reduction and microbial nitrogen fixation, and oxidative degradation by radicals generated through Fenton/Fenton-like reaction. WBC caused aminolysis/ammonolysis and oxidative degradation mainly through dissimilatory nitrate reduction to ammonium and surface free radicals on biochar. These findings indicate that biochar has the potential to accelerate PLA-MP degradation, and its regulatory mechanism depends on the type of biochar.
可生物降解塑料作为石油塑料的替代品正在迅猛发展，但它们在自然条件下不完全降解可能会导致微塑料（MPs）的形成。在这里，我们研究了鸡粪衍生生物炭（MBC）和木废料衍生生物炭（WBC）对聚乳酸微塑料（PLA-MPs）在土壤中一年孵育过程中降解的影响。两种生物炭都使 PLA-MPs 表现出更明显的降解特征，包括增强表面粗糙度、<100μm 的 MPs 比例增加 12.89%-25.67%、氧负载和 O/C 比增加到 71.74%-75.87%和 1.70-1.76，以及加速碳损失和酯基和 C-C 键的断裂。此外，生物炭增加了土壤 pH 值，消耗了无机氮和有效磷，并改变了 PLA-MP 污染土壤中的酶活性。我们提出，两种生物炭通过诱导碱性、氨解/氨化、氧化和微生物降解来加速 PLA-MP 的降解。其中，MBC 通过 Fedriven NO/NO 还原和微生物固氮产生的 NH 诱导氨解/氨化，并通过 Fenton/Fenton 样反应产生的自由基引起氧化降解。WBC 主要通过异化硝酸盐还原为铵和生物炭表面自由基引起氨解/氨化和氧化降解。这些发现表明，生物炭具有加速 PLA-MP 降解的潜力，其调节机制取决于生物炭的类型。
