Abstract In this study, novel polyethylenimine (PEI)-grafted chitosan (CS) core-shell (called as Fe3O4/CS/PEI) magnetic nanoparticles were synthesized and applied for adsorbing phosphate in water. The magnetic and physicochemical properties of as-synthesized nanoparticles were first analyzed by means of a superconducting quantum interference device, X-ray diffractometer, X-ray photoelectron spectroscope, Fourier-transform infrared spectroscope, transmission electron microscope, zeta potential analyzer, and nitrogen sorptiometer. The followed experiments indicated that the amount of phosphate adsorbed increased with increasing equilibrium pH to near 4.0 and then decreased when the pH was further increased. The adsorption isotherms of phosphate on Fe3O4/CS/PEI particles were well fit by the Langmuir equation, and its maximum adsorption was 48.2 mg g−1 at an equilibrium pH of 3.0 and 25 °C. The primary mechanism for phosphate adsorption on Fe3O4/CS/PEI particles was electrostatic attraction. The preferential adsorption of phosphate in the presence of other excess anions including chloride, nitrate, carbonate, and sulfate was presented. Under the conditions studied, more than 90% of phosphate was desorbed from the laden Fe3O4/CS/PEI particles by 0.05 mol L−1 of NaOH solution. The remained adsorption efficiency obtained in the five-cycle reusability tests has demonstrated the promising application potential of Fe3O4/CS/PEI particles.

中文翻译：

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多胺化Fe3O4@壳聚糖核壳磁性纳米粒子的制备用于高效吸附水溶液中的磷酸盐

摘要 本研究合成了新型聚乙烯亚胺（PEI）接枝壳聚糖（CS）核壳（称为Fe3O4/CS/PEI）磁性纳米粒子，并将其用于吸附水中的磷酸盐。首先通过超导量子干涉仪、X 射线衍射仪、X 射线光电子能谱仪、傅里叶变换红外光谱仪、透射电子显微镜、zeta 电位分析仪和氮吸附仪分析了所合成纳米颗粒的磁性和理化性质. 随后的实验表明吸附的磷酸盐量随着平衡 pH 值增加到接近 4.0 而增加，然后当 pH 值进一步增加时减少。磷酸盐在 Fe3O4/CS/PEI 颗粒上的吸附等温线符合朗缪尔方程，最大吸附量为 48。在 3.0 和 25 °C 的平衡 pH 值下为 2 mg g-1。Fe3O4/CS/PEI 颗粒吸附磷酸盐的主要机制是静电吸引。提出了在其他过量阴离子（包括氯离子、硝酸根、碳酸盐和硫酸根）存在下磷酸盐的优先吸附。在研究的条件下，超过 90% 的磷酸盐从负载的 Fe3O4/CS/PEI 颗粒中被 0.05 mol L-1 的 NaOH 溶液解吸。在五次循环可重复使用性测试中获得的剩余吸附效率证明了 Fe3O4/CS/PEI 颗粒的应用潜力。碳酸盐，并出现硫酸盐。在研究的条件下，超过 90% 的磷酸盐从负载的 Fe3O4/CS/PEI 颗粒中被 0.05 mol L-1 的 NaOH 溶液解吸。在五次循环可重复使用性测试中获得的剩余吸附效率证明了 Fe3O4/CS/PEI 颗粒的应用潜力。碳酸盐，并出现硫酸盐。在研究的条件下，超过 90% 的磷酸盐从负载的 Fe3O4/CS/PEI 颗粒中被 0.05 mol L-1 的 NaOH 溶液解吸。在五次循环可重复使用性测试中获得的剩余吸附效率证明了 Fe3O4/CS/PEI 颗粒的应用潜力。