School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China.
China National Environmental Monitoring Centre, Beijing 100012, China.
J Colloid Interface Sci. 2015 May 1;445:93-101. doi: 10.1016/j.jcis.2014.12.082. Epub 2015 Jan 6.
Nanosized magnetic iron oxide was facilely synthesized by a dispersion-precipitation method, which involved acetone-promoted precipitation of colloidal hydrous iron oxide nanoparticles and subsequent calcination of the precipitate at 250°C. Characterization by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, nitrogen sorption, and vibrating-sample magnetometry revealed that the material was a composite of α-Fe2O3 and γ-Fe2O3 with primary particle size of 15-25 nm and specific surface area of 121 m(2)/g, as well as superparamagnetic property. The material was used as adsorbent for the removal of arsenite in water. Batch experiments showed that the adsorption isotherms at pH 3.0-11.0 fit the Langmuir equation and the adsorption obeys pseudo-second-order kinetics. Its maximum sorption capability for arsenite is 46.5 mg/g at pH 7.0. Coexisting nitrate, carbonate, sulfate, chloride, and fluoride have no significant effect on the removal efficiency of arsenite, while phosphate and silicate reduce the removal efficiency to some extent. The As(III) removal mechanism is chemisorption through forming inner-sphere surface complexes. The efficiency of arsenic removal is still maintained after five cycles of regeneration-reuse.
纳米级磁性氧化铁通过分散沉淀法简便合成，该方法涉及在丙酮促进下胶体水合氧化铁纳米颗粒的沉淀，以及沉淀在 250°C 下的煅烧。X 射线衍射、透射电子显微镜、拉曼光谱、氮气吸附和振动样品磁强计的特征分析表明，该材料是α-Fe2O3和γ-Fe2O3的复合物，具有 15-25nm 的初级粒径和 121m2/g 的比表面积以及超顺磁性。该材料被用作水中亚砷酸盐的吸附剂。批量实验表明，pH 值为 3.0-11.0 时的吸附等温线符合朗缪尔方程，吸附符合准二级动力学。在 pH 值为 7.0 时，其对亚砷酸盐的最大吸附容量为 46.5mg/g。共存的硝酸盐、碳酸盐、硫酸盐、氯化物和氟化物对亚砷酸盐的去除效率没有显著影响，而磷酸盐和硅酸盐在一定程度上降低了去除效率。As(III)的去除机制是通过形成内球表面络合物进行化学吸附。经过五次再生-再利用循环后，砷的去除效率仍然保持。
