Ca-Fe基磁性纳米复合材料对水体中磷的结晶回收

人类活动导致大量的不可再生的磷资源流失到水环境中造成水体富营养化，磷的结晶回收对废水治理、地表水管理和可持续发展具有重要意义。采用微波-冷却-回流和超声的方法制备Ca-Fe 基磁性纳米复合材料(CaCO₃-Fe₃O₄)，通过批量吸附实验法系统探究了体系pH、接触时间、磷的初始浓度、共存离子等因素对复合材料去除水体中磷的影响规律。结果表明，CaCO₃-Fe₃O₄纳米磁性复合材料在pH=3.0~6.0内对磷表现出良好的去除效果，对磷的最大去除容量为189.21 mg·g⁻¹。复合材料对水体中的磷主要通过吸附-结晶耦合机制去除，在高浓度含磷废水中，磷以CaHPO₄·2H₂O的形式被回收。综合考虑磁分离的简易性、磷的去除容量和环境友好性，所制备的Ca-Fe基磁性复合材料在磷资源回收领域具有潜在的应用价值。

Crystallization recovery of phosphorus from water by Ca-Fe based magnetic nanocomposites

Human activities induced the loss of non-renewable phosphorus resources into aquatic environment, leading to eutrophication of waterbody. Crystallization recovery of phosphorus is crucial for wastewater treatment, surface water management and sustainable development. In this study, Ca-Fe based magnetic nanocomposites (CaCO3-Fe3O4) were synthesized by microwave-assisted reflux and ultrasound method. The effects of solution pH, contact time, initial phosphorus concentration, coexisting ions on phosphorus removal by magnetic nanocomposite were systematically examined by the batch adsorption method. The results demonstrated that the phosphate could be effectively recovered from water by CaCO3-Fe3O4 nanocomposites in the pH range of 3.0~6.0, and the maximum removal capacity of 189.21 mg·g−1(P). The phosphate was removed via sorption-crystallization coupling mechanism, and in high phosphate concentration effluent, P was harvested in a CaHPO4·2H2O form. Considering the easy magnetic separation, high phosphorus removal capacity and environmental friendliness, the prepared Ca-Fe based magnetic composites have potential applications in phosphorus resource recovery.