This study introduces a facile method for synthesizing covalently bonded magnetic carbon nanoparticles (MCNs) in which carboxylic acid-functionalized activated carbon nanospheres (ACN-COOH) are connected with amine-terminated iron oxide nanoparticles (NPs) (Fe₃O₄-NH₂) via a carbodiimide crosslinking reaction. The adsorption characteristics of the developed magnetic nanoparticles (ACN-Fe₃O₄) were investigated using a standard cationic dye (methylene blue, MB). Two additional MCNs (multi-core and core@shell structures) were also prepared, and their adsorption performances were extensively compared. The developed ACN-Fe₃O₄ material thoroughly utilizes the strengths of activated carbon and Fe₃O₄ themselves, exhibiting large specific surface areas (708.4 m²/g) and strong magnetic properties (40.3 emu/g), resulting in high adsorption capacity (349.5 mg/g) and recycling efficiency (76 % of adsorption performance after four cycles). In addition, a study of the mechanism reveals that pore-filling processes are dominant with minor contributions from electrostatic interactions, π–π interactions, and n–π interactions. The developed covalently bonded magnetic carbon nanoparticles (ACN-Fe₃O₄) can thus be considered as competent adsorbents with the potential to compensate for the drawbacks of contemporary MCNs, such as, low adsorption capacity, and weak magnetic properties.

本研究介绍了一种合成共价键磁性碳纳米粒子 (MCN) 的简便方法，其中羧酸官能化活性炭纳米球 (ACN-COOH) 与胺封端的氧化铁纳米粒子 (NPs) (Fe ₃ O ₄ -NH ₂ ) 通过碳二亚胺交联反应。使用标准阳离子染料（亚甲基蓝，MB）研究了开发的磁性纳米粒子（ACN-Fe ₃ O ₄）的吸附特性。还制备了另外两种 MCN（多核和核@壳结构），并广泛比较了它们的吸附性能。研制的 ACN-Fe ₃ O ₄材料充分利用了活性炭和Fe ₃ O ₄本身的优势，表现出大比表面积（708.4 m ² /g）和强磁性（40.3 emu/g），从而产生高吸附容量（349.5 mg/g）和回收效率（四次循环后吸附性能的 76%）。此外，对该机制的研究表明，孔隙填充过程占主导地位，静电相互作用、π-π 相互作用和 n-π 相互作用的贡献较小。开发的共价键磁性碳纳米粒子（ACN-Fe ₃ O ₄) 因此可以被认为是有能力的吸附剂，有可能弥补当代 MCN 的缺点，例如低吸附能力和弱磁性。