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葡萄糖酸亚铁参与的磁性碳微球及复合体的合成与性能
【作者】 刘洋；
【导师】 付宏刚；
【作者基本信息】 黑龙江大学 ， 无机化学， 2010， 硕士
【摘要】 采用价廉的、可再生的生物质作为碳源,与其分子结构具有一定相似性的葡萄糖酸亚铁为铁源,通过共同水热制备了磁性粒子均匀分散的石墨碳微球。通过XRD、TEM、TG、IR等手段对样品进行表征,结果表明,所合成的磁性石墨碳微球直径为1μm,具有较好的单分散性,磁性粒子均匀分散在石墨碳微球的内部,磁性粒子尺寸约为20-30nm,并对形成机理进行深入探讨,由于葡萄糖酸亚铁与糖类的分子结构具有一定相似性,在水热过程中会同时脱水碳化,从而将Fe(Ⅱ)引入到碳基质当中,在氮气氛下碳化,Fe(Ⅱ)作为催化剂使碳石墨化,而自身被氧化成磁性的Fe3O4粒子。石墨化碳不仅防止磁性粒子团聚同时也起到保护作用,与以往文献报道的磁性碳微球的结构相比较,它自身的稳定性和机械强度均有所增强,这无疑拓展了其应用领域。实验中考察了反应时间、温度、反应物浓度及碳源种类对碳微球形貌及尺寸的影响。此外,磁性石墨碳微球对染料和重金属也展示了良好的吸附性能,并能利用其磁性进行分离,在污水处理、贵金属回收等领域具有潜在的应用价值。利用碳胶球表面存在的大量官能团与金属离子之间的基团配位作用,将金属离子引入到微球表面,在氮气保护下进行碳化后,使金属离子转变成单质或者金属氧化物,同时使碳胶球转变为具有结构稳定和磁性良好的石墨碳微球,制备了MGCS@Ag, MGCS@TiO2(CeO2、ZrO2)复合微球。其中,合成的MGCS@Ag复合体中,Ag粒子均匀的分散在微球表面,尺寸约为30-50 nm,抑菌试验表明MGCS@Ag复合体对大肠杆菌和金色葡萄球菌的生长都具有较好的抑制作用；合成的MGCS@TiO2(CeO2、ZrO2)复合微球可以对α-casein/β-casein酶解产物中的磷酸化肽蛋白的进行富集分离,基本排除非磷酸化肽的干扰,使信噪比显著提高,说明样品对磷酸化肽蛋白具有选择性富集作用,具有潜在的应用价值。
【Abstract】 In this paper, we reports a useful approach to achieve uniform magnetic graphite carbon spheres(MGCS) through synchronous hydrothermal treatment of ferrous gluconate and glucose followed by graphitizing the amorphous carbon at a high temperature. The results of SEM, TEM and XRD revealed that MGCSs with an average diameter of 1 um were synthesized; and magnetic Fe3O4 nanoparticles with diameters from 20 to 25 nm uniformly distributed in MGCSs. Meanwhile, a possible formation mechanisms of MGCS were proposed via the following steps. Firstly, the colloidal carbon spheres (CCSs) with uniformly dispersed Fe(II) and large numbers of hydroxyl groups were synthesized via synchronous hydrothermal reaction of glucose and ferrous gluconate. During the whole reaction, the spontaneous intermolecular dehydration, polymerization and cross-linking among glucouse and ferrous gluconate occurred due to the analogous molecular structure. As a result, Fe(II) disperse throughout the carbonaceous matrix of CCSs. Secondly, after separation and drying, the as-prepared CCSs were calcined under high-purity nitrogen stream. With the decomposition of organic gluconate and glucose during high temperature carbonization, only the adjacent Fe(II) aggregated to form small Fe3O4 nanoparticles due to the separation of carbonaceous matrix. When the temperature further increased, the amorphous carbon around Fe3O4 nanoparticles converted to graphitic carbon. Fe3O4 nanoparticles were enwrapped more compact. The strong confinement effect of the graphitic carbon not only can prevent the aggregation of magnetic Fe3O4 nanoparticles, but also can keep the stability of MGCSs in the solution. In addition, the diameter of the carbon spheres can be adjusted by the hydrothermal reaction condition, such as temperature, time of reaction, and concentration. Synchronously, the MGCSs not only have well adsorbing property as carbon materials, but also possess unusual adsorbing behaviour for heavy metal ions and noble metal ions, which have a significant potential application in the treatment of polluted water and the recovery of noble metal.As mentioned above, there are abundant functional groups on the surface of CCSs resulting from the hydrothermal carbonization, which also provide excellent support to synthesize composite microspheres. The hydroxyl groups of the as-prepared CCSs were also utilized to adsorb Ag+, Ce4+, Zr4+ ions or condensate with Ti-OH. Following a thermal treatment, composite MGCS@Ag or MGCS@TiO2(CeO2, ZrO2) were fabricated. Thereinto, composite MGCS@Ag exhibited excellent properties in antibacterial activity, composite MGCS@TiO2(CeO2, ZrO2) microspheres promising candidates for the enrichment of phosphopeptides and then magnetic-assist separation.