The search for green methods for the synthesis of eco-friendly and sustainable materials is the focus of many studies. In this paper, magnetite nanoparticles (WM-Fe₃O₄) were synthesized using watermelon rind as a stabilizing agent and their adsorption capacity for the removal of lead ions was evaluated. The synthesized WM-Fe₃O₄ was characterized using Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Adsorption capacity and mechanism of WM-Fe₃O₄ for the removal of lead ions from water were evaluated. The adsorption isotherms data were well described by both Langmuir and Freundlich isotherms showing the heterogeneous nature of the adsorbent. Adsorption kinetics followed the pseudo-second-order model which confirmed the heterogeneity of the adsorbent and shows that adsorption followed chemisorption. Adsorption capacity was found to be 138 mg/g for lead. The initial solution pH had an influence on the adsorption. The removal efficiency decreased after pH 7. Effect of varying adsorbent mass indicates that a low dosage is required thereby favouring industrial scale up. The adsorption of lead ions was mainly controlled by electrostatic attraction and polar interactions. This adsorbent has potentials for the efficient capture of heavy metals with possibilities for the future replacement of expensive adsorbents.

寻找合成绿色环保和可持续材料的绿色方法是许多研究的重点。本文以西瓜皮为稳定剂，合成了磁铁矿纳米颗粒（WM-Fe ₃ O ₄），并评价了其吸附去除铅离子的能力。利用傅立叶变换红外光谱，X射线衍射和扫描电子显微镜对合成的WM-Fe ₃ O ₄进行表征。WM-Fe ₃ O _4的吸附容量及机理从水中去除铅离子的方法进行了评估。Langmuir和Freundlich等温线都很好地描述了吸附等温线数据，显示了吸附剂的非均质性。吸附动力学遵循伪二级模型，该模型证实了吸附剂的异质性，并表明吸附遵循化学吸附。发现铅的吸附容量为138 mg / g。初始溶液的pH值对吸附有影响。pH 7后，去除效率降低。吸附剂质量的变化表明需要低剂量，从而有利于工业规模生产。铅离子的吸附主要受静电吸引和极性相互作用的控制。