Li Kun, Qian Jin, Wang Peifang, Wang Chao, Lu Bianhe, Jin Wen, He Xixian, Tang Sijing, Zhang Chao, Gao Pan
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
J Hazard Mater. 2020 Nov 5;398:123030. doi: 10.1016/j.jhazmat.2020.123030. Epub 2020 May 27.
The effect of nanomaterials aging, namely the transformation of comprehensive characteristics after experiencing real or complex environmental behaviors, on their ecotoxicology is still lacking. Moreover, the mechanisms by which NPs influence biological phosphorus (P) removal during sewage treatment require further elucidation. Therefore, we used both pristine and aged anatase (TiO-A) and rutile (TiO-R) NPs to investigate the mechanisms by which NPs affect P removal in a SBR. At 0.1 mg/L, the four types of NPs (pristine and aged) had no significant effect on sludge purification after acute (72-h) exposure under simulated sunlight. However, at 50 mg/L-regardless of the crystalline phase of the NPs-SOP and COD removal efficiency dropped steeply to approximately 42.2-82.4 % (p < 0.05) and 69.8-83.3 % (p < 0.05), respectively, especially in the pristine TiO-NPs groups because of decrease of richness and diversity of genus level of PAOs and enzyme activity of both PPK and PPX, and the sluggish transformation of PHA and glycogen. Aging reduced the ability of NPs toxicity. The toxicity mechanisms of TiO-NPs included lipid peroxidation and contact damage, or leakage from bacterial cytoplasmic membrane, which are closely related to photooxidation capacity and aqueous solution stability-i.e., nanoscale effects-and the impacts of aging or inclusion.
纳米材料老化，即经历真实或复杂环境行为后综合特性的转变，对其生态毒理学的影响仍不明确。此外，纳米颗粒在污水处理过程中影响生物除磷的机制尚需进一步阐明。因此，我们使用原始和老化的锐钛矿型（TiO-A）和金红石型（TiO-R）纳米颗粒，研究纳米颗粒影响序批式反应器（SBR）中磷去除的机制。在0.1 mg/L时，四种类型的纳米颗粒（原始和老化的）在模拟阳光下急性暴露（72小时）后对污泥净化没有显著影响。然而，在50 mg/L时，无论纳米颗粒的晶相如何，溶解性总磷（SOP）和化学需氧量（COD）的去除效率分别急剧下降至约42.2 - 82.4%（p < 0.05）和69.8 - 83.3%（p < 0.05），特别是在原始TiO纳米颗粒组中，这是由于聚磷菌属水平的丰富度和多样性降低以及磷酸烯醇式丙酮酸激酶（PPK）和磷酸葡萄糖变位酶（PPX）的酶活性降低，以及聚羟基脂肪酸酯（PHA）和糖原的转化缓慢。老化降低了纳米颗粒的毒性。TiO纳米颗粒的毒性机制包括脂质过氧化和接触损伤，或细菌细胞质膜泄漏，这与光氧化能力和水溶液稳定性密切相关，即纳米尺度效应，以及老化或包裹的影响。
