College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Hunan University, Changsha, 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Hunan University, Changsha, 410082, PR China.
J Hazard Mater. 2018 Jan 5;341:381-389. doi: 10.1016/j.jhazmat.2017.06.028. Epub 2017 Jun 15.
Nanoremediation strategies applied to contaminated river sediments can induce changes in the mobility and bioavailability of metals with potential consequences on ecosystem health. In this study, the performance of rhamnolipid (RL) coated nanoscale zero-valent iron (NZVI) in immobilizing cadmium (Cd) and lead (Pb) from contaminated river sediments was investigated. We demonstrated that RNZVI was effective in transforming labile Cd and Pb to stable fraction (the maximum residual percentage of Cd and Pb increased by 56.40% and 43.10% after 42days of incubation, respectively), with the decrease of the mobility of metals. The increase of pH in NZVI and RNZVI treated sediment samples indicated the related mechanism for Cd and Pb immobilization. The contents of organic matter (OM) were higher than in control, with the initial addition of RL during 7days incubation, and then the contents gradually decreased and became stable, maybe resulting from the enhancement of the activity of microorganisms and the decomposition of OM. Urease and catalase activities were enhanced with the increase of incubation time, showing certain degrees of recovery in sediment metabolic function. This work provides a new insight into the potential effects of RNZVI applications on the Cd and Pb immobilization in contaminated river sediments.
纳米修复策略应用于受污染的河流沉积物中，可以改变金属的迁移性和生物可利用性，从而对生态系统健康产生潜在影响。本研究考察了鼠李糖脂（RL）包覆的纳米零价铁（NZVI）对受污染河流沉积物中镉（Cd）和铅（Pb）的固定效果。研究结果表明，RNZVI 可有效将可迁移的 Cd 和 Pb 转化为稳定态（孵育 42 天后，Cd 和 Pb 的最大残留比例分别增加了 56.40%和 43.10%），降低了金属的迁移性。NZVI 和 RNZVI 处理的沉积物样品中 pH 值的升高表明了 Cd 和 Pb 固定的相关机制。与对照组相比，在 RL 初始添加的前 7 天，沉积物中的有机质（OM）含量较高，然后逐渐减少并趋于稳定，这可能是由于微生物活性的增强和 OM 的分解。随着孵育时间的延长，脲酶和过氧化氢酶活性增强，表明沉积物代谢功能得到了一定程度的恢复。本研究为 RNZVI 应用对受污染河流沉积物中 Cd 和 Pb 固定的潜在影响提供了新的见解。
