Phosphate (P) is an irreplaceable resource for the growth of all living organisms, and the impending exhaustion of minable P rock arouses the demand of P recovery, which further promotes the novel technologies development. To reclaim the P from wastewater or sludge conveniently and efficiently, a novel magnetic adsorbent with La-Zr bimetallic modification (La-Zr@Fe₃O₄) possessing a high affinity to phosphate and rapid separation was proposed in this study. Adsorption tests showed that the adsorption capacity of P on La-Zr@Fe₃O₄ increased with La content, reaching the maximum value of 49.3 mg/g at pH 3 by L1Z2. Whereas, the addition of La resulted in the decline of desorption efficiency from ~85% to ~60% in the pH range from 3 to 6, except pH 2. The kinetics of P adsorption on the La-Zr@Fe₃O₄ was described well by the pseudo-second-order model, while the isotherm of P adsorption was fitted well by the Freundlich model. Besides, the adsorbent exhibited high selectivity towards P over other coexisting ions (Cl⁻, NO₃⁻, SO₄²⁻, Mg²⁺, and Ca²⁺). The feasibility of P recovery from the solid phase was investigated and confirmed by P recovery from fish farm sludge. The 90% removal efficiency of P and 88% desorption efficiency in cyclic adsorption/desorption experiments evidenced the stability and reusability of La-Zr magnetic adsorbent. The analysis of X-ray diffraction, Fourier transform infrared spectrum, and X-ray photoelectron spectroscopy revealed the replacement of OH⁻ with phosphate via the ligand exchange was the adsorption mechanism. This work demonstrated that the highly efficient, rapidly separable, and repeatable La-Zr@Fe₃O₄ has the potential for phosphate sequestration and recovery.

磷酸盐（P）是所有生物生长的不可替代的资源，矿物质P岩石即将用尽引起了P回收的需求，这进一步促进了新技术的发展。为了方便，有效地从废水或污泥中回收磷，本研究提出了一种新型的La-Zr双金属修饰磁性吸附剂（La-Zr @ Fe ₃ O ₄），对磷酸盐具有高亲和力，并能快速分离。吸附实验表明，P对La-Zr @ Fe ₃ O ₄的吸附能力随着La含量的增加，L1Z2在pH 3下达到最大值49.3 mg / g。鉴于，添加La的导致的解吸效率的下降从〜85％至pH范围为3至6〜60％，pH除外2.磷吸附的的La-Zr的所述动力学@的Fe ₃ ö ₄是拟二阶模型很好地描述了P，而Freundlich模型很好地拟合了P吸附的等温线。此外，吸附剂比其它共存离子（CL显示出高的选择性向P ^-，NO ₃ ^-，SO ₄ ^2-，镁²⁺和Ca ²⁺）。从养鱼场污泥中回收磷已研究并证实了从固相回收磷的可行性。循环吸附/脱附实验中90％的P去除效率和88％的脱附效率证明了La-Zr磁性吸附剂的稳定性和可重复使用性。X射线衍射的分析，傅里叶变换红外光谱和X射线光电子能谱显示更换OH的^-通过配体交换用磷酸盐是吸附机构。这项工作表明，高效，快速可分离且可重复的La-Zr @ Fe ₃ O ₄具有螯合和回收磷酸盐的潜力。