炼钢渣在酸性水溶液中去除 Pb(II)、Cu(II)和 Cd(II)过程中形成的化合物的稳定性。
The stability of the compounds formed in the process of removal Pb(II), Cu(II) and Cd(II) by steelmaking slag in an acidic aqueous solution.
机构信息
Department of Ecological Science and Engineering, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Department of Metallurgy, Graduate School of Engineering, Tohoku University, 02 Aoba-yama, Sendai 980-8579, Japan.
Department of Ecological Science and Engineering, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
出版信息
J Environ Manage. 2019 Feb 1;231:41-48. doi: 10.1016/j.jenvman.2018.10.028. Epub 2018 Oct 13.
The potential feasibility of steel slag as a low cost removal agent for heavy metal ions Pb(II), Cu(II) and Cd(II) in acidic conditions was investigated in this study. The initial pH effect on heavy metal ion removal efficiency, the compounds formed after heavy metal ion removal, and the binding force of metals with the compounds were determined. The results showed that the efficiency of removing heavy metal ions by steel slag was low at low initial pH levels, yet it sharply increased and then became stable as the initial pH increased. The pseudo-second order model provided the best description for the removal of Pb, Cu, and Cd ions, indicating that the predominant heavy metal ion removal mechanism was chemisorption. The images obtained by the Fourier transform infrared spectroscopy (FTIR) and the X-ray diffraction (XRD) analysis indicated that the main compounds formed after the removal of Pb, Cu, and Cd ions by steel slag in an aqueous solution were heavy metal ferrites, silicates, carbonates, hydroxides and oxides. Sequential extraction experiments showed that these three heavy metals bond to the compounds mainly in the carbonate fraction (F), the Fe oxide bound fractions (F (a) and F (c)), and the residual fraction (F) in which F corresponded to the carbonates, and F(a), F(c) and F corresponded to the amorphous or crystalline ferrites and silicates, respectively. The F (a), F (c) and F are relatively stable and do not tend to re-release metal ions in acidic solutions. However, F and heavy metal hydroxides have relatively low stability and dissolve readily, re-leaching heavy metal ions into the acid solution. When these three heavy metal ion mixtures were removed by steel slag, the Pb, Cu and Cd deposits were at higher levels in the F and F fractions. Therefore, it was concluded that the co-existence of heavy metal ions in an aqueous solution is beneficial for their removal by steel slag in acidic conditions.
本研究考察了钢渣作为一种在酸性条件下去除重金属离子 Pb(II)、Cu(II) 和 Cd(II) 的低成本去除剂的潜在可行性。研究了初始 pH 值对重金属离子去除效率的影响、重金属离子去除后形成的化合物以及金属与化合物的结合力。结果表明，钢渣对重金属离子的去除效率在低初始 pH 值时较低，但随着初始 pH 值的增加，去除效率急剧增加并趋于稳定。准二级动力学模型对 Pb、Cu 和 Cd 离子的去除提供了最佳描述，表明主要的重金属离子去除机制是化学吸附。傅里叶变换红外光谱 (FTIR) 和 X 射线衍射 (XRD) 分析的图像表明，钢渣在水溶液中去除 Pb、Cu 和 Cd 离子后形成的主要化合物是重金属铁酸盐、硅酸盐、碳酸盐、氢氧化物和氧化物。顺序提取实验表明，这三种重金属主要与化合物中的碳酸盐部分 (F)、Fe 氧化物结合部分 (F(a) 和 F(c)) 和残余部分 (F) 结合，其中 F 对应于碳酸盐，F(a)、F(c) 和 F 分别对应于无定形或结晶铁酸盐和硅酸盐。F(a)、F(c) 和 F 相对稳定，不易在酸性溶液中重新释放金属离子。然而，F 和重金属氢氧化物的稳定性相对较低，容易溶解，重新将重金属离子浸出到酸溶液中。当钢渣去除这三种重金属离子混合物时，Pb、Cu 和 Cd 沉积物在 F 和 F 部分的含量较高。因此，结论是，水溶液中重金属离子的共存有利于钢渣在酸性条件下对其去除。
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