Mechanism of silicate elution by hydrogen sulfide from bottom sediment in a brackish lake
Mechanism of silicate elution by hydrogen sulfide from bottom sediment in a brackish lake
复制标题
咸水湖底泥硫化氢洗脱硅酸盐的机理
DOI：
10.1007/s10201-019-00601-2
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发表时间：
2020
期刊：
影响因子：
1.6
通讯作者：
Michiko Egawa and Yasushi Seike
中科院分区：
文献类型：
--
作者：
Ja Yeong Park;Shogo Sugahara;Michiko Egawa and Yasushi Seike
在微咸水湖Nakaumi湖缺氧还原沉积物的孔隙水中检测到高浓度的溶解硅酸盐。夏季硅酸盐浓度也与总硫化氢浓度同步增加。通常情况下，溶解的硅酸盐很容易被氢氧化铁吸附并在氧化环境中沉淀。在这项研究中，我们重点研究了氢氧化铁吸附沉积物中硅酸盐的行为，并确定了硫化氢是吸附硅酸盐的氢氧化铁洗脱溶解硅酸盐的主要原因，因为在缺氧还原环境中通过微生物过程产生的硫化氢对其他金属氧化物是可还原的。根据实验室实验，氢氧化铁与硫化钠反应生成硅酸盐，随着溶液中硫化钠浓度的增加，溶解硅酸盐从缺氧还原沉积物中的淋洗量增加。这一结果表明，在还原环境下，硫化氢对硅酸盐的释放是非常关键的。因此，在Nakaumi湖，吸附硅酸盐的氢氧化铁在夏季还原环境中与硫化氢反应后，将从底部释放硅酸盐。
Highly concentrated dissolved silicate was detected in pore water from anoxic-reducing sediment in Lake Nakaumi, a brackish lake. Silicate concentration also simultaneously increased with total hydrogen sulfide concentration during the summer. Generally, dissolved silicate is readily adsorbed onto ferric hydroxide and precipitates in an oxidative environment. In this study, we focused on the behavior of ferric hydroxide adsorbing silicate in sediment and determined that hydrogen sulfide was the main cause of dissolved silicate elution from ferric hydroxide adsorbing silicate because the hydrogen sulfide produced via microbiological processes in the anoxic-reducing environment was reducible for other metal oxides. According to laboratory experiments, silicate was released from ferric hydroxide by reacting with sodium sulfide, causing increasing elution of dissolved silicate from anoxic-reducing sediments with increasing concentration of sodium sulfide in the solutions. This result shows that hydrogen sulfide is very crucial for silicate release under a reducing environment. Therefore, in Lake Nakaumi, silicate would be released from the bottom after ferric hydroxide adsorbing silicate reacted with hydrogen sulfide in a summer reductive environment.