The effectiveness and mechanism of aluminum/iron co-modified calcite (Al/Fe-CA) for the control of phosphorus (P) liberation from sediments was investigated. The results showed that Al/Fe-CA possessed good sorption performance for phosphate, and the maximum phosphate sorption capacity for Al/Fe-CA could reach 27.0 mg/g. The major mechanisms involved the surface adsorption of phosphate on calcite, the precipitation between phosphate and Ca²⁺ leached from calcite, and the ligand exchange between Al/Fe-bound hydroxyl groups and phosphate to form the Al–O–P and Fe–O–P inner-sphere complexes. The re-releasing risk of Al/Fe-CA-bound P under the circumstances of normal pH (5–9) and reducing environment was very low. Al/Fe-CA addition could significantly reduce the risk of P releasing from sediment to overlying water (OL-water), and the inactivation of mobile P, reactive soluble P (SRP) and diffusive gradient in thin-films (DGT)-labile P in sediment by Al/Fe-CA had a great part in the suppression of sediment-P liberation to OL-water by the Al/Fe-CA amendment. Al/Fe-CA capping and fabric-wrapped Al/Fe-CA capping both could greatly reduce the risk of P releasing from sediment into OL-water, and the formation of a static layer with low concentrations of SRP and DGT-labile P in the upper sediment was the key to sustaining a high P controlling efficiency. When the applied mode of Al/Fe-CA varied from capping to amendment, although the inactivation efficiency of DGT-labile P in the overlying water and upper sediment by Al/Fe-CA would decrease to a certain degree, the inactivation efficiency of DGT-labile P in the lower sediment by Al/Fe-CA would increase. Results of this study suggest that Al/Fe-CA has the high potential to be used as an active capping or amendment material for the management of internal P loading in surface water bodies.

研究了铝/铁共改性方解石 (Al/Fe-CA) 控制沉积物中磷 (P) 释放的有效性和机制。结果表明，Al/Fe-CA对磷酸盐具有良好的吸附性能，对Al/Fe-CA的最大磷酸盐吸附量可达27.0 mg/g。主要机理包括磷酸盐在方解石上的表面吸附、磷酸盐与Ca ²⁺之间的沉淀从方解石中浸出，Al/Fe结合的羟基和磷酸盐之间的配体交换形成Al-O-P和Fe-O-P内球复合物。在正常pH（5-9）和还原环境下，Al/Fe-CA结合的P的再释放风险非常低。添加 Al/Fe-CA 可以显着降低 P 从沉积物释放到上覆水 (OL-water) 的风险，以及流动 P、反应性可溶性 P (SRP) 和薄膜中扩散梯度 (DGT) 不稳定的失活Al/Fe-CA 对沉积物中 P 的抑制作用在 Al/Fe-CA 修正物抑制沉积物 P 释放到 OL-水中方面发挥了重要作用。Al/Fe-CA 封盖和织物包裹的 Al/Fe-CA 封盖都可以大大降低 P 从沉积物释放到 OL 水中的风险，在上层沉积物中形成具有低浓度 SRP 和 DGT 不稳定 P 的静态层是维持高 P 控制效率的关键。当Al/Fe-CA的施用方式从封盖到改良时，虽然Al/Fe-CA对上覆水和上层沉积物中DGT不稳定P的灭活效率会有所下降，但DGT的灭活效率Al/Fe-CA 在下部沉积物中的 - 不稳定 P 会增加。这项研究的结果表明，Al/Fe-CA 具有用作活性封盖或改良材料以管理地表水体中内部 P 负载的巨大潜力。虽然Al/Fe-CA对上覆水体和上层沉积物中DGT不稳定P的灭活效率会有所降低，但Al/Fe-CA对下层沉积物中DGT不稳定P的灭活效率会提高。这项研究的结果表明，Al/Fe-CA 具有用作活性封盖或改良材料以管理地表水体中内部 P 负载的巨大潜力。虽然Al/Fe-CA对上覆水体和上层沉积物中DGT不稳定P的灭活效率会有所降低，但Al/Fe-CA对下层沉积物中DGT不稳定P的灭活效率会提高。这项研究的结果表明，Al/Fe-CA 具有用作活性封盖或改良材料以管理地表水体中内部 P 负载的巨大潜力。