Lönnrot Satu, Suorsa Valtteri, Paajanen Johanna, Hatanpää Timo, Ritala Mikko, Koivula Risto
Department of Chemistry, FI-00014 University of Helsinki P. O. box 55 Finland
RSC Adv. 2019 Jul 18;9(39):22355-22365. doi: 10.1039/c9ra04211c. eCollection 2019 Jul 17.
Mesoporous and large surface area zirconium oxide aggregate granules with good adsorption properties were synthesized using a simple precipitation method. Since utilization of these small and fragile particles is considered rather difficult in larger scale column operation, the product was formed into a fibrous form to improve its usability. The submicron fibers were obtained from an optimized electroblowing synthesis that resulted in elastic and uniform fibers with a tetragonal structure and high length-to-diameter ratio. In antimonate (Sb(v)) adsorption experiments, the higher calcination temperature (350 °C) of the fibers did not seem to decrease the Sb(v) adsorption capacity excessively since the high theoretical adsorption capacities were 113 mg g and 58 mg g for the aggregate and fibers, respectively. Both materials had fast kinetics, fibers being faster in the beginning of the reaction. Moreover, both materials offered efficient Sb(v) removal in the studied pH range from 1 to 11 by reaching over 99.9% adsorption in the optimal pH range. X-ray absorption near edge spectroscopy (XANES) revealed that Sb(v) stays as pentavalent antimony after being adsorbed by these materials and based on the isoelectric point shifts in the zeta potential measurement, adsorption occurs mainly by an inner-sphere complexation reaction. Finally, our study showed that pressure buildup in a flow-through column packed with zirconium oxide fibers was significantly lower than in a column packed with aggregates. Thus, zirconium oxide aggregates can be formed into submicron fibers with enhanced column operation properties without a too large compromise in the adsorption properties.
采用简单沉淀法合成了具有良好吸附性能的介孔大比表面积氧化锆聚集体颗粒。由于在大规模柱操作中使用这些细小且易碎的颗粒被认为相当困难，因此将产物制成纤维形式以提高其可用性。亚微米纤维是通过优化的电吹合成法获得的，该方法产生了具有四方结构和高长径比的弹性均匀纤维。在锑酸盐（Sb(v)）吸附实验中，纤维较高的煅烧温度（350℃）似乎并未过度降低Sb(v)的吸附容量，因为聚集体和纤维的理论吸附容量分别为113 mg/g和58 mg/g。两种材料都具有快速的动力学，纤维在反应开始时更快。此外，在研究的pH范围1至11内，两种材料都能有效去除Sb(v)，在最佳pH范围内吸附率超过99.9%。X射线吸收近边光谱（XANES）表明，Sb(v)被这些材料吸附后仍以五价锑的形式存在，并且基于zeta电位测量中的等电点变化，吸附主要通过内球络合反应发生。最后，我们的研究表明，填充氧化锆纤维的流通柱中的压力积累明显低于填充聚集体的柱。因此，氧化锆聚集体可以制成具有增强柱操作性能的亚微米纤维，而在吸附性能上不会有太大的折衷。
