College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, PR China.
College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, PR China.
Environ Pollut. 2017 Aug;227:444-450. doi: 10.1016/j.envpol.2017.04.074. Epub 2017 May 6.
Nano zero valent iron/Ni bimetal materials (nZVI/Ni) were prepared by borohydride reduction method to remediate toxic Cr(Ⅵ) contaminated in soil leachate. nZVI/Ni was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Different factors including pH value of soil leachate, reaction time, temperature, humic acid and coexisting anions (SO, NO, HCO, CO) were studied to analyze the reduction rate. Results showed that the reduction rate of Cr(Ⅵ) could reach 99.84% under the condition of pH of 5 and temperature of 303 K. pH values and temperature of soil leachate had a significant effect on the reduction efficiency, while humic acid had inhibition effect for the reduction reaction. SO, HCO and CO had inhibition effect for reduction rate, while NO barely influenced the reduction process of nZVI/Ni. Moreover, Langumir-Hinshelwood first order kinetic model was studied and could describe the reduction process well. The thermodynamic studies indicated that the reaction process was endothermic and spontaneous. Activation energy was 143.80 kJ mol, showing that the reaction occurred easily. Therefore, the study provides an idea for nZVI/Ni further research and practical application of nZVI/Ni in soil remediation.
采用硼氢化钠还原法制备纳米零价铁/镍双金属材料（nZVI/Ni），以修复土壤渗滤液中有毒的 Cr(Ⅵ)污染。采用扫描电子显微镜（SEM）、X 射线衍射（XRD）和 X 射线光电子能谱（XPS）对 nZVI/Ni 进行了表征。研究了不同因素，包括土壤渗滤液的 pH 值、反应时间、温度、腐殖酸和共存阴离子（SO、NO、HCO、CO），以分析还原率。结果表明，在 pH 值为 5 和温度为 303 K 的条件下，Cr(Ⅵ)的还原率可达 99.84%。土壤渗滤液的 pH 值和温度对还原效率有显著影响，而腐殖酸对还原反应有抑制作用。SO、HCO 和 CO 对还原速率有抑制作用，而 NO 对 nZVI/Ni 的还原过程几乎没有影响。此外，还研究了 Langmuir-Hinshelwood 一级动力学模型，该模型可以很好地描述还原过程。热力学研究表明，反应过程是吸热和自发的。反应活化能为 143.80 kJ/mol，表明反应容易发生。因此，该研究为 nZVI/Ni 的进一步研究以及 nZVI/Ni 在土壤修复中的实际应用提供了思路。
