一步法制备磁性PEI-Fe_(3)O_(4)/La(OH)_(3)去除微污染水体中磷的研究

One-step preparation of magnetic PEI-Fe_(3)O_(4)/La(OH)_(3) for phosphorus removal in micro-polluted water

低浓度磷的深度去除是缓解水体富营养化的关键.本研究采用共沉淀法制备了聚乙烯亚胺(PEI)修饰的Fe_(3)O_(4)/La(OH)_(3)磁性除磷剂,研究发现该材料对磷酸根具有良好的吸附性能,其吸附符合Langmuir等温模型和准二级动力学模型,理论最大吸附量为87.09 mg·g^(-1).Fe_(3)O_(4)/La(OH)_(3)在竞争性离子(SO_(4)^(2-)、Cl^(-)和NO_(3)^(-))存在下对磷酸根仍具有特异吸附能力.通过磁铁对吸附剂进行回收再利用,5次吸附-脱附循环过程中磷酸盐去除率维持在90%以上.同时,在实际微污染水体(PO_(4)^(3-)浓度<1 mg·L^(-1))的处理中体现出良好的净化效果.蒙特卡洛模型计算显示,PEI-Fe_(3)O_(4)/La(OH)_(3)经济成本较低且环境友好.综上所述,PEI-Fe_(3)O_(4)/La(OH)_(3)是一种具有实际应用前景的除磷材料.

It is of key importance to remove the low concentrations of phosphorus in water to prevent the occurrence of eutrophication.In this study,a magnetic PEI-Fe_(3)O_(4)/La(OH)_(3) adsorbent was prepared by co-precipitation method and used for the removal of phosphate.The adsorption behavior of PEI-Fe_(3)O_(4)/La(OH)_(3) was consistent with the Langmuir isothermal model and the pseudo-second-order kinetic model.The PEI-Fe_(3)O_(4)/La(OH)_(3) exhibited a fast adsorption and a high theoretical maximum adsorption capacity of 87.09 mg·g^(-1).Moreover,the coexisting ions(SO_(4)^(2-),Cl-and NO_(3)^(-)) had no significant effect on the phosphate adsorption.Recovered by a magnet,the phosphate removal rate of PEI-Fe_(3)O_(4)/La(OH)_(3) was maintained at about 90%after five adsorption-desorption cycles.Significantly,the PEI-Fe_(3)O_(4)/La(OH)_(3) exhibited an effective performance in the treatment of actual micropolluted water(PO_(4)^(3-)<1 mg·L^(-1)).Monte Carlo model simulations showed that PEI-Fe_(3)O_(4)/La(OH)_(3) served as an adsorbent with economic and environmental advantages.All these results suggest that PEI-Fe_(3)O_(4)/La(OH)_(3) is a promising candidate for phosphate removal in real applications.