The use of biopolymers obtained from natural resources as a carbon source has attracted much attention. In this study, we introduced a novel method for synthesis of hollow magnetic carbon microbeads (HMCMs) based on core-shell alginate hydrogel microbeads consisting of a hydrophobic iron-oleate core encapsulated in a shell of ionically cross-linked alginate hydrogel using the syringe pump with the fabricated double-layered syringe needle. This allows in-situ formation of magnetic particles and carbon walls simultaneously during carbonization. After surface passivation with a silica coating followed by direct carbonization led to in-situ formation of iron oxide particles via the thermal decomposition of the iron-oleate precursor in the core region and a carbon shell derived from the cross-linked alginate polymer during carbonization. The subsequent removal of the silica shell resulted in the formation of HMCMs with a unique surface wrinkle morphology and superparamagnetic property. HMCMs were applied to remove dye from the contaminated wastewater, and the dye-adsorbed HMCMs could be easily removed by an external magnetic field. The proposed synthesis of hollow carbon microbeads can be further optimized to control the size of core-shell microbeads and the components encapsulated in the core and shell, and hence will be useful for preparing diverse types of beads for various applications.

中文翻译：

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油酸铁@藻酸盐核壳水凝胶合成空心磁性碳微珠及其在有机染料磁分离中的应用

从自然资源中获得的生物聚合物作为碳源的使用引起了很多关注。在这项研究中，我们介绍了一种基于核壳海藻酸盐水凝胶微珠合成空心磁性碳微珠 (HMCM) 的新方法，该微珠由使用注射泵包裹在离子交联海藻酸盐水凝胶壳中的疏水油酸铁核组成。与制造的双层注射器针头。这允许在碳化过程中同时原位形成磁性颗粒和碳壁。在用二氧化硅涂层进行表面钝化后，然后直接碳化，通过在碳化过程中核心区域油酸铁前体和源自交联藻酸盐聚合物的碳壳的热分解，在原位形成氧化铁颗粒。随后去除二氧化硅壳导致形成具有独特表面皱纹形态和超顺磁性的 HMCM。HMCMs 用于去除污染废水中的染料，吸附染料的 HMCMs 可以通过外部磁场轻松去除。所提出的空心碳微珠的合成可以进一步优化，以控制核壳微珠的尺寸以及包裹在核壳中的成分，因此将有助于制备用于各种应用的不同类型的微珠。