Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha 410083, PR China.
School of Metallurgy and Environment, Central South University, Changsha 410083, PR China.
J Hazard Mater. 2021 Aug 5;415:125551. doi: 10.1016/j.jhazmat.2021.125551. Epub 2021 Mar 1.
Various ferrites modified carbon nanotubes (MFeO/CNTs; M = Co, Cu, Mn) were synthesized and characterized using TEM-EDS, FTIR, BET, TG-DTA, VSM, and XRD. MFeO/CNTs were used as adsorbents for removing ciprofloxacin (CIP), and the adsorption mechanism was revealed in a comparative manner based on the experimental results and density functional theory calculations. The adsorption capacities of CIP on MFeO/CNTs were 63.32 (Co), 61.60 (Cu), and 46.35 (Mn) mg/g, respectively. Different M components of MFeO affected the adsorption behavior of CIP on them, while the specific surface area and total pore volume showed no significant impact. The investigation on the adsorption energy and the bond formation indicated that CIP was more favorably captured by CoFeO/CuFeO than MnFeO. The local density of states of metal atoms and O atoms (from the ketone or carboxyl groups of CIP) showed that the d-band centers of Co and Cu atoms were above the Fermi level, while that of Mn was below the Fermi level, providing the fundamental understanding of the promoted O adsorption on CoFeO and CuFeO and restrained adsorption on MnFeO. This observation was supported by the electron localization function in terms of the stronger charge density overlap between Co-O/Cu-O than that of Mn-O.
采用 TEM-EDS、FTIR、BET、TG-DTA、VSM 和 XRD 等方法对各种改性碳纳米管的铁氧体（MFeO/CNTs；M=Co、Cu、Mn）进行了合成和表征。MFeO/CNTs 被用作吸附剂来去除环丙沙星（CIP），并根据实验结果和密度泛函理论计算，以对比的方式揭示了吸附机制。CIP 在 MFeO/CNTs 上的吸附容量分别为 63.32（Co）、61.60（Cu）和 46.35（Mn）mg/g。不同的 M 组分的 MFeO 影响 CIP 在其上的吸附行为，而比表面积和总孔体积没有显著影响。对吸附能和键形成的研究表明，CIP 更有利于被 CoFeO/CuFeO 捕获，而不是 MnFeO。金属原子和 O 原子（来自 CIP 的酮基或羧基）的局域态密度表明，Co 和 Cu 原子的 d 带中心高于费米能级，而 Mn 原子的低于费米能级，这为 CoFeO 和 CuFeO 上促进的 O 吸附以及 MnFeO 上抑制的吸附提供了基本的理解。电子定域函数表明 Co-O/Cu-O 之间的电荷密度重叠比 Mn-O 更强，这支持了这一观察结果。
