School of Environmental Science and Engineering, Southwest Jiaotong University, Chengdu 611756, China.
Sichuan Academy of Eco-Environmental Sciences, Chengdu, 610000, China.
Chemosphere. 2024 Sep;363:142878. doi: 10.1016/j.chemosphere.2024.142878. Epub 2024 Jul 18.
Adsorption methods offer efficient recovery of phosphorus from water bodies. Modification adsorption materials combining lanthanum (La) and zirconium (Zr) dual-metal immobilized via co-precipitation method have been widely applied in the adsorption and recovery of phosphate. Meanwhile, sodium carbonate (NaCO) is gradually replacing sodium hydroxide (NaOH) as the mainstream co-precipitant for immobilizing metals into supporting matrices due to its excellent performance and environmental friendliness. However, the adsorption mechanisms of materials synthesized with different co-precipitants and the synergistic effects between dual-metal components are not well understood, which is not conducive to the further optimization of dual-metal adsorption materials. In this study, anion exchange resin was utilized as the supporting matrices, and La&Zr dual-metal-modified materials, La&Zr-CO and La&Zr-OH, were prepared using NaCO and NaOH as co-precipitants, respectively. The results indicate that La&Zr-CO exhibits superior performance in phosphate adsorption and recovery, with adsorption capacity and recovery efficiency reaching 36.28 mg/g and 82.59%, respectively. Additionally, this material demonstrates strong stability in reuse, phosphate selectivity, and a wide pH applicability range. La&Zr-CO achieves phosphate adsorption through surface electrostatic affinity, ligand exchange, and intraspherical complexation, whereas La&Zr-OH primarily relies on electrostatic adsorption on the surface and interior of the material. Synergistic effects between La and Zr result in enhanced adsorption performance of the dual-metal material compared to individual metals. Specifically, phosphate adsorption is predominantly governed by La, while the presence of Zr further enhances ligand exchange between lattice oxygen and metals. Simultaneously, Zr doping enhances the phosphate recovery capacity and reusability of the materials. Continuous flow adsorption results from actual water bodies demonstrate that La&Zr-CO is more suitable for the removal and recovery of phosphate in water treatment engineering. This study provides a theoretical basis and technical support for the adsorption and recovery of phosphate using dual-metal-modified materials.
吸附法是从水体中回收磷的有效方法。通过共沉淀法将镧（La）和锆（Zr）双金属固定化的改性吸附材料已广泛应用于磷酸盐的吸附和回收。同时，由于碳酸钠（NaCO）具有良好的性能和环境友好性，正在逐渐取代氢氧化钠（NaOH）作为主流共沉淀剂，将金属固定到支撑基质中。然而，对于不同共沉淀剂合成的材料的吸附机制以及双金属成分之间的协同作用尚不清楚，这不利于进一步优化双金属吸附材料。本研究以阴离子交换树脂为支撑基质，分别以碳酸钠（NaCO）和氢氧化钠（NaOH）为共沉淀剂，制备了镧&锆（La&Zr）双金属改性材料 La&Zr-CO 和 La&Zr-OH。结果表明，La&Zr-CO 在磷酸盐吸附和回收方面表现出优异的性能，吸附容量和回收率分别达到 36.28mg/g 和 82.59%。此外，该材料在重复使用、磷酸盐选择性和宽 pH 适用性方面表现出较强的稳定性。La&Zr-CO 通过表面静电亲和力、配体交换和球内络合作用实现磷酸盐的吸附，而 La&Zr-OH 主要依赖于材料表面和内部的静电吸附。La 和 Zr 的协同作用使双金属材料的吸附性能得到增强。具体而言，磷酸盐吸附主要由 La 控制，而 Zr 的存在进一步增强了晶格氧与金属之间的配体交换。同时，Zr 掺杂增强了材料的磷酸盐回收容量和可重复使用性。实际水体的连续流动吸附结果表明，La&Zr-CO 更适合用于水处理工程中磷酸盐的去除和回收。本研究为双金属改性材料吸附和回收磷酸盐提供了理论依据和技术支持。
