Magnetic hollow carbon microspheres as a reusable adsorbent for rhodamine B removal
Magnetic hollow carbon microspheres as a reusable adsorbent for rhodamine B removal
复制标题
磁性空心碳微球作为可重复使用的吸附剂用于去除罗丹明 B
作者：
鲁菲菲;黄慈;游力军;王家斌;张其清
采用微波辅助缩聚和无表面活性剂乳液聚合相结合的方法制备了具有空腔和多孔碳壳双重结构的磁性空心碳微球。通过透射电镜、X射线衍射、热重分析、振动样品磁强计和N2吸附/脱附等温线对MHCM进行了表征。MHCM具有均匀的形态、高表面积（680 m2 g-1）、大孔体积（0.61 cm 3 g-1）和磁响应性的特征。将MHCM用作吸附剂以去除罗丹明B（RB）。RB的去除率达到99.5%，MHCM的吸附容量高达300 mg g-1。吸附过程符合Langmuir等温式。焓变为28.35 kJ mol-1。吸附自由能变化为负值，说明吸附过程是自发进行的。正熵变表明吸附体系的无序度增加。去除过程是吸热的，相互作用控制。吸附动力学符合准二级动力学模型。连续6次循环后RB的去除率仍保持在90%以上，表明MHCM具有较高的吸附性能和良好的可重复使用性。
Magnetic hollow carbon microspheres (MHCMs) were fabricated with a dual alternative constitution of cavities and porous carbon shells by a combination of microwave-assistant polycondensation and surfactant-free emulsion polymerization. The MHCM was characterized by transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometry and N2 adsorption/desorption isotherms. The MHCMs possessed features of uniform morphologies, high surface area (680 m2 g−1), large pore volume (0.61 cm3 g−1) and magnetic responsiveness. The MHCMs were used as an adsorbent to remove rhodamine B (RB). The removal efficiency of RB reached 99.5% and the adsorption capacity of the MHCMs reached as high as 300 mg g−1. The adsorption process followed the Langmuir isotherm very well. The enthalpy change was 28.35 kJ mol−1. The negative free energy change indicated that the adsorption process was feasible and spontaneous. The positive entropy change showed that there was an increase in disorder in the adsorption system. The removal process was endothermic and interaction controlled. The adsorption kinetics fitted well with the pseudo-second-order kinetics model. The removal efficiency of RB remained over 90% after six consecutive cycles, which demonstrated the high adsorption performance and favourable reusability of the MHCMs.