State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
Department of Physics, Tongji University, Shanghai, 200092, People's Republic of China.
Environ Sci Pollut Res Int. 2019 Jan;26(1):806-815. doi: 10.1007/s11356-018-3631-5. Epub 2018 Nov 10.
This study reports the preparation of highly dispersed nanoscale zerovalent iron (nZVI) with core-shell structure decorated onto graphene nanosheets (Gr-NS) to form nZVI-Gr-NS composite. Meanwhile, its excellent performance for concentrated Zn(II) wastewater treatment is also studied. The adsorption of Zn(II) onto nZVI-Gr-NS is well simulated by the pseudo-second-order model, which indicates the adsorption is the rate-controlling step. Moreover, the adsorption isotherms of Zn(II) on the nZVI-Gr-NS can fit well with the Langmuir model. The negative thermodynamic parameters (△G, △H, △S) calculated from the temperature-dependent isotherms indicate that the sorption reaction of Zn(II) is an exothermic and spontaneous process. The high saturation magnetization (37.4 emu g) of the nZVI-Gr-NS makes separation of nZVI-Gr-NS-bound Zn(II) easily and quickly from aqueous solution. Most importantly, nZVI-Gr-NS composites not only remove Zn(II) but also spontaneously remove As, Se, and Cu ions from real smelting wastewater samples. This study provides a good solution for heavy metal removal in real wastewater.
本研究制备了高度分散的核壳结构纳米零价铁（nZVI）负载在石墨烯纳米片（Gr-NS）上，形成 nZVI-Gr-NS 复合材料。同时，研究了其对高浓度 Zn(II)废水的处理性能。采用拟二级动力学模型很好地模拟了 Zn(II)在 nZVI-Gr-NS 上的吸附过程，表明吸附是速率控制步骤。此外，Zn(II)在 nZVI-Gr-NS 上的吸附等温线可以很好地符合 Langmuir 模型。从温度相关等温线上计算得到的负热力学参数（△G、△H、△S）表明，Zn(II)的吸附反应是一个放热和自发的过程。nZVI-Gr-NS 具有较高的饱和磁化强度（37.4 emu g），使得 nZVI-Gr-NS 结合的 Zn(II)很容易从水溶液中快速分离。最重要的是，nZVI-Gr-NS 复合材料不仅能去除 Zn(II)，还能自发地从实际冶炼废水中去除 As、Se 和 Cu 等离子。本研究为实际废水中重金属的去除提供了一个很好的解决方案。
