Abstract The alkali magnesium iron phosphate KMgFe(PO4)2 was synthesized by sol gel method and was characterized by XRD, SEM, IR and magnetic susceptibility measurements. The purity and the structure of the obtained phase were analyzed by X-ray diffraction and structural refinement. The prepared sample crystallized in monoclinic system, space group C2/c, and adopted a lamellar structure. The chemical composition and morphology were confirmed by scanning electron microscopy. IR spectroscopy verified the presence of only PO43− group in the structure. Magnetic measurements revealed an antiferromagnetic behavior with TN = 2.7 K. The methylene blue adsorption process was evaluated as a function of various operating parameters such as contact time, pH, temperature and concentration. The experimental data were analyzed using several kinetic models: the pseudo first order, pseudo second order and intraparticle diffusion. The pseudo second order model described successfully the adsorption of methylene blue on the synthesized compounds. The experimental isotherm data were analyzed by the Langmuir, Freundlich and Temkin models. The equilibrium data were well-fitted with the Langmuir model.

中文翻译：

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层状单磷酸铁KMgFe(PO4)2的溶胶-凝胶合成、磁性和亚甲基蓝吸附性能

摘要 采用溶胶凝胶法合成了碱金属磷酸铁镁KMgFe(PO4)2，并通过XRD、SEM、IR和磁化率测量对其进行了表征。通过X射线衍射和结构精修分析所得相的纯度和结构。制备的样品结晶为单斜晶系，空间群为C2/c，呈层状结构。通过扫描电子显微镜确认化学成分和形态。红外光谱证实结构中仅存在 PO43- 基团。磁性测量揭示了 TN = 2.7 K 的反铁磁行为。将亚甲蓝吸附过程评估为各种操作参数（例如接触时间、pH、温度和浓度）的函数。使用几种动力学模型分析实验数据：伪一阶、伪二阶和粒子内扩散。伪二阶模型成功地描述了亚甲蓝在合成化合物上的吸附。实验等温线数据通过 Langmuir、Freundlich 和 Temkin 模型进行分析。平衡数据与朗缪尔模型拟合良好。