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采用化学共沉淀法,以聚乙烯亚胺(PEI)为改性剂,制备了聚乙烯亚胺改性的纳米四氧化三铁复合材料(Fe3O4/PEI).Zeta电位、透射电镜和FTIR表征结果显示,PEI修饰提高了纳米Fe3O4在水中的分散性和稳定性,同时也增强了其表面正电荷,从而提高了Fe3O4对水中磷酸根的去除能力.在磷酸根初始浓度为50 mg·L~(-1),Fe3O4/PEI投加量为200 mg,p H=3,温度为25℃的条件下,Fe3O4/PEI对100 m L磷酸根的吸附去除率达到91%.吸附过程在3 h内达到平衡.吸附等温数据表明,该吸附过程符合Langmuir吸附等温方程,可决系数R2达到0.99,最大吸附量为29.88 mg·L~(-1).Fe3O4/PEI复合材料重复利用性好,在第5次吸附-解析后还能保持对磷酸根75%以上的吸附去除率.磷的解析效率随着p H增加而增加,在p H=13时,解析效率达到65%.
Polyethyleneimine (Fe3O4 / PEI) modified by polyethyleneimine was prepared by chemical coprecipitation method using polyethyleneimine (PEI) as modifier.The results of Zeta potential, transmission electron microscopy and FTIR characterization Showed that the PEI modification increased the dispersibility and stability of nano-Fe3O4 in water and also enhanced the positive charge on the surface of Fe3O4, thereby enhancing the removal ability of Fe3O4 to phosphate in water.Under the initial phosphate concentration of 50 mg · L ~ (-1) -1), Fe3O4 / PEI dosage of 200 mg, p H = 3, the adsorption and desorption rate of Fe3O4 / PEI to 100 m L phosphate was 91% under the condition of 25 ℃ .The adsorption process within 3 h The adsorption isotherm data showed that the adsorption process accorded with Langmuir adsorption isotherm equation, the coefficient of determination R2 reached 0.99 and the maximum adsorption capacity was 29.88 mg · L -1 .The reusability of Fe3O4 / PEI composites was good, After 5 times of adsorption-desorption, the adsorption removal rate of more than 75% of phosphate was maintained. The analytical efficiency of phosphorus increased with the increase of p H, and the analytical efficiency reached 65% at p H = 13.