Bai Yaohui, Jefferson William A, Liang Jinsong, Yang Tingting, Qu Jiuhui
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2017 Apr;54:126-134. doi: 10.1016/j.jes.2016.05.026. Epub 2016 Jul 4.
Antimony (Sb), which can be toxic at relatively low concentrations, may co-exist with Mn(II) and/or Fe(II) in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb (III and V) species in the presence of Mn(II) and Mn-oxidizing bacteria, with or without Fe(II). Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides (BMOs), which were formed in-situ via the oxidation of Mn(II) by a Mn-oxidizing bacterium (Pseudomonas sp. QJX-1). Results indicated that Sb(III) ions could be oxidized to Sb(V) ions by BMO, but only Sb(V) originating from Sb(III) oxidation was adsorbed effectively by BMO. Introduced Fe(II) was chemically oxidized to FeOOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe-Mn oxides (BFMO). The BMO part of the BFMO mainly oxidized and the FeOOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As(III) and Sb(III), the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe(II), As(III) and Sb(III) accelerated the oxidation of Mn(II) but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn(II) in aquatic ecosystems, with or without Fe(II).
锑（Sb）在相对较低浓度下就可能具有毒性，在一些地下水和地表水体中可能与二价锰（Mn(II)）和/或二价铁（Fe(II)）共存。在此，我们研究了在有或没有Fe(II)存在的情况下，Sb（III和V）物种在Mn(II)和锰氧化细菌存在时的潜在氧化和吸附途径。进行了批量实验，以确定在生物源锰氧化物（BMOs）存在下Sb物种的氧化和吸附特性，这些生物源锰氧化物是通过锰氧化细菌（假单胞菌属QJX-1）对Mn(II)的原位氧化形成的。结果表明，Sb(III)离子可被BMO氧化为Sb(V)离子，但只有源自Sb(III)氧化的Sb(V)能被BMO有效吸附。引入的Fe(II)被化学氧化为FeOOH，其沉淀物与BMO混合形成一种新化合物，生物源铁锰氧化物（BFMO）。BFMO中的BMO部分主要起氧化作用，BFMO中的FeOOH主要吸附Sb物种。在同时含有As(III)和Sb(III)的水溶液中，原位形成 的BFMO优先氧化Sb而非As，但对As的吸附效率更高。化学分析和逆转录实时聚合酶链反应表明，Fe(II)、As(III)和Sb(III)的存在加速了Mn(II)的氧化，但抑制了锰氧化细菌的活性。这些结果为水生生态系统中有无Fe(II)时Sb、Mn(II)的生物地球化学途径提供了重要见解。
