The different chemical behavior of anionic As and cationic Cd and Pb makes the simultaneous stabilization of soils contaminated with arsenic (As), cadmium (Cd), and lead (Pb) challenging. The use of soluble, insoluble phosphate materials and iron compounds cannot simultaneously stabilize As, Cd, and Pb in soil effectively due to the easy re-activation of heavy metals and poor migration. Herein, we propose a new strategy of “cooperatively stabilizing Cd, Pb, and As with slow-release ferrous and phosphate”. To very this theory, we developed ferrous and phosphate slow-release materials to simultaneously stabilize As, Cd, and Pb in soil. The stabilization efficiency of water-soluble As, Cd and Pb reached 99% within 7d, and the stabilization efficiencies of NaHCO₃-extractable As, DTPA-extractable Cd and Pb reached 92.60%, 57.79% and 62.81%, respectively. The chemical speciation analysis revealed that soil As, Cd and Pb were transformed into more stable states with the reaction time. The proportion of residual fraction of As, Cd, and Pb increased from 58.01% to 93.82%, 25.69 to 47.86%, 5.58 to 48.54% after 56 d, respectively. Using ferrihydrite as a representative soil component, the beneficial interactions of phosphate and slow-release ferrous material in stabilizing Pb, Cd, and As were demonstrated. The slow-release ferrous and phosphate material reacted with As and Cd/Pb to form stable ferrous arsenic and Cd/Pb phosphate. Furthermore, the slow-release phosphate converted the adsorbed As into dissolved As, then the dissolved As reacted with released ferrous to form a more stable form. Concurrently, As, Cd and Pb were structurally incorporated into the crystalline iron oxides during the ferrous ions-catalyzed transformation of amorphous iron (hydrogen) oxides. The results demonstrates that the use of slow-release ferrous and phosphate materials can aid in the simultaneous stabilization of As, Cd, and Pb in soil.

阴离子 As 和阳离子 Cd 和 Pb 的不同化学行为使得同时稳定受砷 (As)、镉 (Cd) 和铅 (Pb) 污染的土壤具有挑战性。由于重金属容易再活化且迁移性差，使用可溶性、不溶性磷酸盐材料和铁化合物不能同时有效稳定土壤中的As、Cd和Pb。在此，我们提出了“协同稳定 Cd、Pb 和 As 与缓释亚铁和磷酸盐”的新策略。根据这一理论，我们开发了亚铁和磷酸盐缓释材料以同时稳定土壤中的 As、Cd 和 Pb。7d内水溶性As、Cd、Pb的稳定效率达到99%，NaHCO _{3的稳定效率}-可萃取As、DTPA可萃取Cd和Pb分别达到92.60%、57.79%和62.81%。化学形态分析表明，随着反应时间的延长，土壤 As、Cd 和 Pb 转化为更稳定的状态。56 d后，As、Cd、Pb的残留比例分别从58.01%上升到93.82%、25.69%上升到47.86%、5.58%上升到48.54%。使用水铁矿作为代表性土壤成分，证明了磷酸盐和缓释亚铁材料在稳定 Pb、Cd 和 As 方面的有益相互作用。缓释亚铁和磷酸盐材料与 As 和 Cd/Pb 反应形成稳定的亚铁砷和 Cd/Pb 磷酸盐。此外，缓释磷酸盐将吸附的砷转化为溶解的砷，然后溶解的砷与释放的亚铁发生反应，形成更稳定的形式。同时，作为，在非晶态铁（氢）氧化物的亚铁离子催化转化过程中，Cd 和 Pb 在结构上结合到结晶铁氧化物中。结果表明，使用缓释亚铁和磷酸盐材料有助于同时稳定土壤中的 As、Cd 和 Pb。