Guo Rui-Feng, Ma Yan-Qing, Liu Zhi-Hong
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 PR China
RSC Adv. 2019 Jun 26;9(35):20009-20018. doi: 10.1039/c9ra03654g. eCollection 2019 Jun 25.
The 3D hierarchical porous 7MgO·2BO·7HO (MBH) microspheres were prepared by a phase transformation of chloropinnoite firstly, and anhydrous α-3MgO·BO (MBA) microspheres were obtained by thermal conversion of 7MgO·2BO·7HO, and then β-3MgO·BO (MBB) microspheres were obtained by phase conversion of α-3MgO·BO. All samples were characterized by XRD, FT-IR, TG and SEM. The microsphere nanostructures with a hierarchical porous structure were assembled by nanosheets with a thickness of 20-30 nm, and the growth mechanisms were also proposed. By using N adsorption-desorption, the specific surface areas were measured as 103.62 m g for MBH and 46.10 m g for MBA. They exhibited excellent selective adsorption performance for Congo red (CR) with maximum adsorption capacities of 202.84 and 170.07 mg g respectively, and the corresponding adsorption mechanisms were also investigated. The adsorption processes were well fitted with the pseudo-second-order rate equation and Langmuir adsorption model. In addition, the corresponding adsorption thermodynamic parameters were also calculated. It is necessary to highlight that the hierarchical porous microspheres could be considered as promising candidates for removal of CR dye pollutants.
首先通过氯柱硼镁石的相变制备了三维分级多孔7MgO·2B₂O₃·7H₂O（MBH）微球，然后通过7MgO·2B₂O₃·7H₂O的热转化得到无水α-3MgO·B₂O₃（MBA）微球，接着通过α-3MgO·B₂O₃的相转变得到β-3MgO·B₂O₃（MBB）微球。所有样品均通过XRD、FT-IR、TG和SEM进行表征。具有分级多孔结构的微球纳米结构由厚度为20 - 30 nm的纳米片组装而成，并提出了生长机制。通过N₂吸附 - 脱附，测得MBH的比表面积为103.62 m²/g，MBA的比表面积为46.10 m²/g。它们对刚果红（CR）表现出优异的选择性吸附性能，最大吸附容量分别为202.84和170.07 mg/g，并对相应的吸附机制进行了研究。吸附过程很好地符合准二级速率方程和朗缪尔吸附模型。此外，还计算了相应的吸附热力学参数。需要强调的是，分级多孔微球可被视为去除CR染料污染物的有前途的候选材料。
