School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China.
School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China.
J Hazard Mater. 2021 Feb 5;403:123728. doi: 10.1016/j.jhazmat.2020.123728. Epub 2020 Aug 19.
The release of highly toxic tellurite into the aquatic environment poses significant environmental risks. The acceleration mechanism and tellurium nanorods (TeNPs) characteristics with bioavailable ferric citrate (Fe(III)) were investigated in the tellurite (Te(IV)) bioreduction. Experiments showed that 5 mM Fe(III) increased the Te(IV) bioreduction rate from 0 to 12.40 mg/(L·h). Cyclic voltammetry, electrochemical impedance spectroscopy and Tafel were used to investigate electron transfer during Te(IV) bioreduction. NADH production (electron production) was significantly enhanced to 138% by Fe(III). Meanwhile Fe(III) stimulated the increase of cytochrome c, resulting in increased electron transport system activity. In addition, Fe(III) facilitated the secretion of extracellular polymeric substances (EPS) and reduced cell membrane permeability, thus reducing the toxicity of Te(IV) to cells. The increase of ATP provided energy for the metabolic process of Te(IV) bioreduction, playing an active role in cell activity. Based on the above analysis, the acceleration mechanism of Fe(III) on Te(IV) bioreduction was proposed from the aspects of electron generation, electron transfer and energy level. Zeta potential and FT-IR spectra indicated that the stability of TeNPs contributed to the covered EPS. This study provides further understanding the acceleration mechanism of Te(IV) bioreduction and promising strategy for improving the stability of TeNPs.
将高毒性亚碲酸盐释放到水生环境中会带来重大的环境风险。本研究考察了生物可利用的柠檬酸铁(Fe(III))对亚碲酸盐(Te(IV))生物还原的加速机制和碲纳米棒(TeNPs)特性。实验表明,5 mM 的 Fe(III)将 Te(IV)的生物还原速率从 0 提高到 12.40 mg/(L·h)。循环伏安法、电化学阻抗谱和 Tafel 法用于研究 Te(IV)生物还原过程中的电子转移。Fe(III)使 NADH 的产生(电子产生)显著提高到 138%。同时,Fe(III)刺激细胞色素 c 的增加,从而增加电子传递系统的活性。此外,Fe(III)促进了细胞外聚合物(EPS)的分泌并降低了细胞膜的通透性,从而降低了 Te(IV)对细胞的毒性。增加的 ATP 为 Te(IV)生物还原的代谢过程提供了能量,在细胞活性中发挥了积极作用。基于上述分析,从电子生成、电子传递和能级的角度提出了 Fe(III)对 Te(IV)生物还原的加速机制。Zeta 电位和 FT-IR 图谱表明,TeNPs 的稳定性归因于覆盖的 EPS。该研究为进一步了解 Te(IV)生物还原的加速机制和提高 TeNPs 稳定性提供了有前景的策略。