POPs Research Center, School of Environment, Tsinghua University, Beijing, P. R. China.
Environ Sci Technol. 2012 Apr 17;46(8):4576-82. doi: 10.1021/es203876e. Epub 2012 Mar 29.
A novel Ni-Fe bimetal with high dechlorination activity for 4-chlorophenol (4-CP) was prepared by ball milling (BM) in this study. Increasing Ni content and milling time greatly enhanced the dechlorination activity, which was mainly attributed to the homogeneous distribution of Ni nanoparticles (50-100 nm) in bulk Fe visualized by scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) with image mapping. In comparison with the Ni-Fe bimetal prepared by a chemical solution deposition (CSD) process, the ball milled Ni-Fe bimetal possessed high dechlorination activity and stability before being used up. Dechlorination kinetics indicated that the dechlorination rates of 4-CP increased with increasing Ni-Fe dose but decreased with increasing solution pH. Solution pH had a significant effect on the dechlorination of 4-CP and the passivation of the Ni-Fe bimetal. The enhanced pH during the dechlorination process significantly accelerated the formation of passivating film on the bimetallic surface. The Ni-Fe bimetal at the dose of 60 g/L was reused 10 times without losing dechlorination activity for 4-CP at initial pH less than 6.0, but the gradual passivation was observed at initial pH above 7.0.
本研究通过球磨（BM）制备了一种具有高效脱氯活性的新型 Ni-Fe 双金属，用于 4-氯苯酚（4-CP）的脱氯。增加 Ni 含量和球磨时间可显著提高脱氯活性，这主要归因于 Ni 纳米颗粒（50-100nm）在扫描电子显微镜/能谱（SEM/EDS）图像映射中均匀分布于块状 Fe 中。与通过化学溶液沉积（CSD）过程制备的 Ni-Fe 双金属相比，球磨制备的 Ni-Fe 双金属在耗尽之前具有较高的脱氯活性和稳定性。脱氯动力学表明，4-CP 的脱氯速率随 Ni-Fe 剂量的增加而增加，但随溶液 pH 值的增加而降低。溶液 pH 值对 4-CP 的脱氯和 Ni-Fe 双金属的钝化有显著影响。脱氯过程中增强的 pH 值显著加速了双金属表面钝化膜的形成。在初始 pH 值小于 6.0 时，剂量为 60g/L 的 Ni-Fe 双金属可重复使用 10 次而不失去对 4-CP 的脱氯活性，但在初始 pH 值大于 7.0 时，观察到逐渐的钝化。
