Abstract Although the conventional zirconium-based solid-phase phosphorus (P)-inactivating agents (ZrPIAs) have high potential for controlling P release from sediments in aquatic systems, they are difficultly retrieved from sediments after their application. Therefore, it is very necessary to develop new ZrPIAs that can be readily retrieved from sediments after their application. In this study, a novel magnetic ZrPIA, i.e., zirconia/magnetite/zeolite composite (ZMZ) was prepared, characterized and used as a sediment amendment to control the release of P from sediments. The adsorption performance and mechanism of phosphate on ZMZ were studied using batch experiments and XPS analysis. The impact of ZMZ addition on the releasing flux of P from sediments to the overlying water as well as on the fractionation and bioavailability of P in sediments was studied using microcosm incubation experiments. In addition, the stability of P captured by ZMZ was also investigated. Results showed that ZMZ exhibited high adsorption ability towards phosphate, with a maximum phosphate adsorption capacity of at least 4.1 mg P/g, and phosphate adsorption onto ZMZ was mainly controlled by inner-sphere complex formation mechanism. The ZMZ addition greatly decreased the releasing flux of P from sediments into the overlying water in anoxic environment, with a DTP (dissolved total P) reduction efficiency of 61.8–97.8%. Moreover, the added ZMZ could immobilize mobile P in sediments by changing P species from Na2S2O4/NaHCO3-extractable P (BD-P) to NaOH-extractable P (NaOH-rP) and residual P (Res P). Furthermore, the bioavailability of P in sediments could be reduced by the addition of ZMZ. The stability evaluation of P captured by ZMZ after its application showed that a majority of P adsorbed by ZMZ existed in the form of NaOH-rP and Res P, which were difficult to be re-released into the water column under common pH (5–9) and reducing condition. In summary, the above results demonstrate the high potential for the application of ZMZ as an amendment in the control of P release from sediments.

中文翻译：

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用于控制沉积物磷释放的氧化锆/磁铁矿/沸石复合材料的合成与评价：实验室研究

摘要 尽管传统的锆基固相磷（P）灭活剂（ZrPIAs）在控制水生系统沉积物中磷释放方面具有很高的潜力，但它们在应用后很难从沉积物中回收。因此，开发新的 ZrPIAs 是非常必要的，这些 ZrPIAs 在应用后可以很容易地从沉积物中回收。在这项研究中，一种新型磁性 ZrPIA，即氧化锆/磁铁矿/沸石复合材料 (ZMZ) 被制备、表征并用作沉积物改良剂以控制沉积物中 P 的释放。采用批量实验和XPS分析研究了磷酸盐在ZMZ上的吸附性能和机理。使用微观孵化实验研究了ZMZ添加对P从沉积物到上覆水的释放通量以及沉积物中P的分馏和生物有效性的影响。此外，还研究了 ZMZ 捕获的 P 的稳定性。结果表明，ZMZ 对磷酸盐表现出较高的吸附能力，最大磷酸盐吸附容量至少为 4.1 mg P/g，并且 ZMZ 上的磷酸盐吸附主要受内球复合物形成机制的控制。ZMZ的添加大大降低了缺氧环境下沉积物中P释放到上覆水中的通量，DTP（溶解总P）降低效率为61.8-97.8％。而且，添加的 ZMZ 可以通过将 P 种类从 Na2S2O4/NaHCO3 可提取 P (BD-P) 更改为 NaOH 可提取 P (NaOH-rP) 和残留 P (Res P) 来固定沉积物中的移动 P。此外，添加 ZMZ 可以降低沉积物中 P 的生物有效性。ZMZ 应用后对 P 的稳定性评价表明，ZMZ 吸附的大部分 P 以 NaOH-rP 和 Res P 的形式存在，在一般 pH（5- 9）和还原条件。综上所述，上述结果表明，ZMZ 作为控制沉积物中磷释放的改良剂具有很高的潜力。ZMZ 应用后对 P 的稳定性评价表明，ZMZ 吸附的大部分 P 以 NaOH-rP 和 Res P 的形式存在，在一般 pH（5- 9）和还原条件。综上所述，上述结果表明，ZMZ 作为控制沉积物中磷释放的改良剂具有很高的潜力。ZMZ 应用后对 P 的稳定性评价表明，ZMZ 吸附的大部分 P 以 NaOH-rP 和 Res P 的形式存在，在一般 pH（5- 9）和还原条件。综上所述，上述结果表明，ZMZ 作为控制沉积物中磷释放的改良剂具有很高的潜力。