| 摘要: |
| 增加硅酸盐供给可缓解海域硅酸盐相对缺乏现象，稻壳灰中含有大量无定形态SiO2，是一种理想的海水硅酸盐肥料。为验证稻壳灰的硅酸盐释放性能以及在环境中应用时的安全性，我们在实验室内将稻壳灰添加到海水中测定了Si、P、N营养盐的释放能力及释放周期，并将稻壳灰放于自然海域浸泡一段时间后测定其4种重金属及Mg元素含量的变化。实验结果表明，稻壳灰在海水中可持续缓慢地释放硅酸盐，释放周期可达3个月以上，同时释放少量磷酸盐，不会增加水体中无机氮营养盐含量；稻壳灰向海水中释放极少量的Cd，但不易造成重金属污染，而对海水中的Cu、Pb、Hg有一定地吸附效果，吸附量远小于Mg离子。 |
| 关键词: 稻壳灰 硅限制 硅酸盐肥料 重金属 |
| DOI：10.11759/hykx20190414001 |
| 分类号:P76 |
| 基金项目:中国科学院战略性先导科技专项（XDA23050401）；中国科学院科技服务网络计划（Y82346101L）；国家重点基础研究发展计划（973）项目（2015CB452903） |
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| Effectiveness and safety of rice husk ash as a seawater silicate fertilizer |
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LV Jing-jing1,2,3, ZHANG Guang-tao1,3
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1.Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2.University of Chinese Academy of Sciences, Beijing 100049, China;3.Pilot National Laboratory for Marine Science and Technology, Qingdao 266071, China
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| Abstract: |
| Rice husk ash (RHA) has the potential to be used as a silicate fertilizer to alleviate silicate deficiency in seawater. This study was conducted to evaluate the fertility and environmental safety of RHA by analyzing the macronutrient-releasing capability and the duration of RHA in seawater in the laboratory and by investigating the temporal variation of heavy metals and Mg content in RHA at two coastal sites in the Jiaozhou Bay. In the laboratory, RHA released the dissolved silicate content continuously for more than 3 months, with rates ranging from 0.31 to 4.15 μmol/g/d. Phosphate release was observed only during the initial 2 weeks, whereas changes in dissolved inorganic nitrogen concentration were not detected. Soaking in natural seawater for 3 weeks increased the concentrations of Cu, Pb, and Hg of RHA but slightly decreased the Cd concentration. This suggested that heavy metal absorptivity of RHA was outcompeted by other metal ions present in large amount in seawater such as Mg. Our results confirmed the potential of RHA as a suitable silicate fertilizer for silicate-limited eutrophicated waters; however, the possibility to use it as either an efficient heavy metal absorber or a releaser could not be confirmed. |
| Key words: rice husk ash silicate deficiency silicate fertilizer heavy metal |
