Soil dissolved organic matter affects mercury immobilization by biogenic selenium nanoparticles.
Soil dissolved organic matter affects mercury immobilization by biogenic selenium nanoparticles.
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DOI：
10.1016/j.scitotenv.2018.12.091
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Xiaonan Wang;Xiangliang Pan;G. Gadd
中科院分区：
文献类型：
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作者：
Xiaonan Wang;Xiangliang Pan;G. Gadd
分子量的不均一性是土壤中溶解性有机物的一个基本性质，它影响着有机物与纳米颗粒的结合行为。本研究从黑土中提取DOM，将其透析为大于10，000 Da、3500- 10，000 Da、1000-3500 Da和100-1000 Da四个组分。均聚和荧光猝灭滴定的硒纳米粒子（SeNPs）的存在下，不同的DOM馏分，以及固定的元素汞的后果进行了检查。发现中等MW级分（3500- 10，000 Da）而不是高MW DOM级分可能吸附到SeNP。一般来说，低分子量的DOM预计最初吸附由于更快的扩散，这些化合物将被取代高分子量的DOM在较长的时间内。然而，静电势垒赋予吸附DOM限制这种位移，导致优先吸附的中间MW馏分超过高MW馏分。吸附DOM馏分，特别是中间MW，增强了硒纳米颗粒的稳定性，有利于固定元素汞。这些研究结果表明，MW发挥了重要的影响DOM与SeNPs的结合，因此，管理的命运SeNPs和汞生物修复性能。
Molecular weight (MW) heterogeneity is a fundamental property of dissolved organic matter (DOM) in soil, which has been demonstrated to influence the binding behaviour between DOM and engineered nanoparticles. In the present study, DOM, extracted from black soil, was dialyzed into four fractions: above 10,000 Da, 3500–10,000 Da, 1000–3500 Da and 100–1000 Da. Homoaggregation and fluorescence quenching titration of selenium nanoparticles (SeNPs) was examined in the presence of the different DOM fractions, as well as the consequences for immobilization of elemental mercury. It was found that the intermediate MW fraction (3500–10,000 Da) rather than the high MW DOM fraction was likely to adsorb to SeNPs. Generally, low MW DOM was expected to adsorb initially due to faster diffusion and these compounds would be displaced by high MW DOM over longer time period. However, the electrostatic barrier imparted by adsorbed DOM limited such displacement, leading to preferential adsorption of the intermediate MW fraction over the high MW fraction. Adsorbed DOM fractions, especially that of intermediate MW, enhanced the stability of SeNPs which favoured immobilization of elemental mercury. These findings show that MW exerts an important impact on DOM binding with SeNPs which, in consequence, governs the fate of SeNPs and mercury bioremediation performance.