钝化剂添加对湖泊底泥有机磷组分变化及转化规律的影响

In situ passivation technique has characteristics of easy operation and excellent effect. Therefore, it was used widely in the controlling pollutants of sediments.Many studies have found that the phosphorus passivation agent could significantly reduce the contents of mobile phosphorus in the sediment (the sum of labile phosphorus, iron-bound phosphorus and organic phosphorus), especially for the content of organic phosphorus. however, the mechanisms and causes of organic phosphorus component change are still unclear, so it is difficult to grasp the using dose and application method of passivation agent, hindered the applationof in situ passivation technique for lake restoration. Contents of activity phosphorus in the sediment can be reduced by addition of passivation agent. Components of Organic phosphorus are also affected by addition of passivation agent as an important part of active phosphorus. In this study, we used the Self-developed calcium-rich clay minerals to carry out the research of laboratory and in situ sediment capping. Sequential extraction procedure, 31 P-nuclear magnetic resonance (31 P -NMR) technology and 32 P isotopic tracer technique were used to analyze the changes of composition of organophosphorus and transformation rules and fate behavior, Sediment organic phosphorus transformation characteristics were dissected by analyzing the Composition changes of inorganic and organic phosphorus, organic phosphorus transformation rules in the sediment affected by passivation agent were revealed through summary indoor and field analysis results. This could provide a scientific support to the government of lake pollution control.

底泥磷原位钝化技术作为一种操作简单、效果明显的湖泊内源磷控制手段已经越来越被应用富营养化湖泊治理之中。大量的研究发现，磷钝化剂的添加会显著降低底泥可移动磷（弱吸附态磷、铁结合态磷和有机磷之和）的含量，尤其是有机磷的含量。然而，钝化剂添加对底泥有机磷组分变化的原因和机制仍不清楚，难以掌握钝化剂在湖泊中的施用剂量和方法，阻碍了底泥磷原位钝化技术在湖泊治理中的应用。本课题基于自主研发的富钙粘土为材料，开展室内培养和现场钝化实验，基于磷化学形态提取和31P-核磁共振及32P同位素示踪等技术，研究钝化剂添加对底泥有机磷组分变化的影响；通过分析无机与有机磷构成变化以及有机磷在多介质（沉积物、钝化剂和间隙水）中的分布，剖析底泥有机磷转化特征，总结分析室内与现场分析结果，揭示钝化剂添加对底泥有机磷组分变化的影响与作用机制，为我国富营养化湖泊治理提供科学依据。

有机磷是湖泊内源磷的主要组成部分，而目前对钝化剂与底泥有机磷的作用机制仍不明晰，严重影响了钝化剂在浅水湖泊中的应用。本项目采用热改性富钙凹凸棒为研究对象，基于磷形态化学提取和31P-核磁共振技术，研究钝化剂添加对底泥有机磷组分变化特征的影响；通过无机与有机磷构成变化分析，剖析底泥有机磷转化特征，研究结果发现，添加锁磷剂覆盖后上覆水及沉积物中有效磷通量有显著地降低，沉积物-水界面处“过渡层”逐渐下移且宽度逐渐增加。控制上覆水为酸性和碱性的实验组上覆水及沉积物中有效磷通量均有显著地降低，且控制上覆水为酸性的实验组有效磷通量一直较碱性实验组低；材料覆盖后活性有机磷NaHCO3-Po含量减少，转化为性质较稳定的中等活性有机磷HCl-Po，31P-NMR分析结果表示添加钝化剂覆盖前后,沉积物中正磷酸盐、焦磷酸盐、磷酸单酯、DNA-P含量均有明显降低。添加钝化剂覆盖对表层沉积物中的有解磷功能的假单胞菌属和无色杆菌属有一定的抑制作用，但影响不显著，说明钝化作用是以化学作用为主，生物作用为辅。