Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
Chemosphere. 2022 Feb;288(Pt 2):132581. doi: 10.1016/j.chemosphere.2021.132581. Epub 2021 Oct 14.
In this study, a novel nanoscale iron oxide (FeO) modified carbon nanotubes composite (FeO@CNTs) was synthesized through a combined ball milling-hydrothermal two-step method and tested for aqueous Sb(III) removal efficiency and mechanisms. FeO nanoparticles was successfully loaded on the surface of CNTs through functional groups such as hydroxyl (-OH), C-H, and C-O to enhance the removal efficiency of Sb(III) through adsorption and surface complexation. At a dosage of 0.02 g, a FeCl·6HO-to-CNTs mass ratio of 3:1, and an initial solution pH of 6.3, the amount of Sb(III) removed by the prepared FeO@CNTs reached 172 mg/g, which was 42.9 times higher than that of the pristine CNTs (4.01 mg/g). Chemical adsorption and oxidation were the main removal mechanisms. At the equilibrium Sb(III) concentration of 6.08 mg/L, 6.56% of initial Sb(III) was adsorbed onto the surface of FeO@CNTs, and 81.3% of initial Sb(III) was oxidized to Sb(V) with lower toxicity. The pseudo-second-order kinetic model could better describe the adsorption of Sb(III) onto the FeO@CNTs composite, indicating that adsorption was mainly controlled by chemical sorption. In the adsorption isotherm equation, the Redlich-Peterson model provided a better fit of Sb(III) adsorption onto the FeO@CNTs composite than the Langmuir and Freundlich models, which further indicated that the adsorption process was a hybrid removal process dominated by chemical sorption. The presence of CO slightly promoted the removal of Sb(III) from aqueous solution. The synthesized composite was magnetic and could be easily separated from the solution by an external magnetic field at the end of the sorption experiment. Based on these findings, the FeO@CNTs nanocomposite is expected to provide an environmentally-friendly adsorbent with a strong sorption capacity for remediating Sb(III) in water environments.
在这项研究中，通过结合球磨-水热两步法合成了一种新型纳米氧化铁（FeO）修饰的碳纳米管复合材料（FeO@CNTs），并测试了其对水中 Sb(III) 的去除效率和机制。FeO 纳米颗粒通过羟基（-OH）、C-H 和 C-O 等官能团成功负载在 CNTs 表面，通过吸附和表面络合增强了 Sb(III) 的去除效率。在剂量为 0.02 g、FeCl·6HO 与 CNTs 的质量比为 3:1、初始溶液 pH 值为 6.3 的条件下，制备的 FeO@CNTs 对 Sb(III) 的去除量达到 172 mg/g，比原始 CNTs（4.01 mg/g）高 42.9 倍。化学吸附和氧化是主要的去除机制。在平衡 Sb(III)浓度为 6.08 mg/L 的情况下，有 6.56%的初始 Sb(III)被吸附到 FeO@CNTs 表面，81.3%的初始 Sb(III)被氧化为毒性较低的 Sb(V)。准二级动力学模型能更好地描述 Sb(III)在 FeO@CNTs 复合材料上的吸附，表明吸附主要受化学吸附控制。在吸附等温方程中，Redlich-Peterson 模型比 Langmuir 和 Freundlich 模型更能拟合 Sb(III)在 FeO@CNTs 复合材料上的吸附，进一步表明吸附过程是一种以化学吸附为主的混合去除过程。CO 的存在略微促进了 Sb(III)从水溶液中的去除。合成的复合材料具有磁性，在吸附实验结束时可以通过外部磁场很容易地从溶液中分离出来。基于这些发现，FeO@CNTs 纳米复合材料有望成为一种具有强吸附能力的环保吸附剂，用于修复水环境中的 Sb(III)。
