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首页> 外文期刊>Environmental Science & Technology >Dissolved Black Carbon Facilitates Photoreduction of Hg(Ⅱ) to Hg(0) and Reduces Mercury Uptake by Lettuce (Lactuca sativa L)
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Dissolved Black Carbon Facilitates Photoreduction of Hg(Ⅱ) to Hg(0) and Reduces Mercury Uptake by Lettuce (Lactuca sativa L)

机译：溶解的黑色碳有助于Hg（Ⅱ）至Hg（0）的映射，并通过莴苣（Lactuca sativa L）减少汞摄取

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摘要

Here, we investigated the photoreduction of Hg(Ⅱ) (Hg(NO_3)_2) mediated by dissolved black carbon (DBC, <0.45 μm size fraction) collected from water extracts of biochar derived by pyrolyzing crop residues (rice, soybean, and peanut). Under simulated sunlight conditions, the presence of 5 mg C/L DBC significantly facilitated the production of Hg(0) from Hg(Ⅱ) (initially at 10 nmol/L) with a reduction ratio of 73 ± 4% in 5.3 h. Inhibition of photolysis-induced reactive oxygen species by a quencher or removal of dissolved oxygen indicated that Hg(Ⅱ) was mainly reduced by superoxide anion (O_2~(•-)). Reduction by electrons transferred from photoexcited DBC components or by organic free radicals produced from photo-Fenton-like reactions was also proposed to play a role. Contrary to dissolved humic substances, the DBC-mediated photoreduction of Hg(Ⅱ) led to unique positive mass-independent isotopic fractionation (MIF) of Hg(0) (△~(199)Hg = 1.8 ± 0.3‰), which was attributed to the dominance of secondary Hg(Ⅱ) reduction by O_2~(•-). The leachate from soil amended with rice biochar at 1-5% mass ratios exhibited significantly higher photo catalytic efficiency than that from unamended soil (wherein the reduced Hg(0) increased from 27 ± 1 to 63 ± 2% in maximum), and the efficiency positively correlated with the percentage of amended biochar. Under natural illumination conditions, the total mercury and/or methylmercury uptake by roots, shoots, and leaves of lettuce (Lactuca sativa L.) grown in water extracts of rice biochar-amended soil was consistently lower (up to 70 ± 20%) than that without the biochar amendment. The findings highlight that DBC might play an important and previously unrecognized role in the biogeochemical cycle and the environmental impact of mercury.
机译：在这里，我们研究了通过从热解作物残留物（水稻，大豆和花生的生物炭水提取物中，由溶解的黑碳（DBC，<0.45μm尺寸分数）介导的Hg（Ⅱ）（Hg（NO_3）_2）的光诊断）。在模拟的阳光条件下，5mg C / L DBC的存在显着促进了从Hg（Ⅱ）（最初在10nmol / L）的Hg（0）的产生，减少比例为73±4％。通过猝灭剂抑制光解诱导的反应性氧物质或去除溶解氧表明Hg（Ⅱ）主要由超氧化物阴离子（O_2〜（• - ））降低。还提出了由光屏蔽的DBC组分或由光纤样反应产生的有机自由基转移的电子减少，以发挥作用。与溶解的腐殖物质相反，Hg（Ⅱ）的DBC介导的光电导致Hg（0）的独特的阳性质量独立同位素分级（MIF）（△〜（199）Hg = 1.8±0.3‰）归因于通过O_2〜（• - ）减少二级HG（Ⅱ）的优势。从1-5％质量比的水稻Biochar修正的土壤的渗滤液显着较高的照片催化效率明显高于未解脱的土壤（其中，降低的Hg（0）最大值增加到27±1至63±2％），以及效率正相关与修正的生物炭的百分比相关。在自然的照明条件下，莴苣（Lactuca Sativa L.）在水稻生物炭修正的土壤中生长的根，芽和甲基汞（Lactuca Sativa L.）的汞含量始终较低（高达70±20％）没有生物炭修正案。调查结果强调，DBC可能在生物地理循环中发挥重要且以前无法识别的作用和汞的环境影响。

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  • 来源
    《Environmental Science & Technology》 |2020年第18期|11137-11145|共9页
  • 作者

    Langlang Li; Xuejun Wang; Heyun Fu; Xiaolei Qu; Jiubin Chen; Shu Tao; Dongqiang Zhu;

  • 作者单位

    School of Urban and Environmental Sciences Key Laboratory of the Ministry of Education for Earth Surface Processes Peking University Beijing 100871 China;

    School of Urban and Environmental Sciences Key Laboratory of the Ministry of Education for Earth Surface Processes Peking University Beijing 100871 China;

    State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Jiangsu 210046 China;

    State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University jiangsu 210046 China;

    Institute of Surface-Earth System Science Tianjin University Tianjin 300072 China;

    School of Urban and Environmental Sciences Key Laboratory of the Ministry of Education for Earth Surface Processes Peking University Beijing 100871 China;

    School of Urban and Environmental Sciences Key Laboratory of the Ministry of Education for Earth Surface Processes Peking University Beijing 100871 China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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