Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095, PR China.
Mater Sci Eng C Mater Biol Appl. 2013 Oct;33(7):3723-9. doi: 10.1016/j.msec.2013.05.006. Epub 2013 May 10.
In this paper, the facilitating role of biogenetic jarosite in the reduction of Cr(VI) by sulfide and its mechanism were investigated through batch experiments and analysis of X-ray photoelectron spectrum (XPS). To study the effects of operational parameters on the reduction of Cr(VI) by sulfide, four operational parameters (pH of solution, operation temperature, loading of jarosite and reaction time) were considered as input variables for response surface methodology (RSM). Graphical response surfaces and contour plots were used to evaluate the effect of interaction between operational parameters on the reduction of Cr(VI). The results suggest that a cycle process of converting Fe(III) to Fe(II) occurred on the surface of jarosite and markedly accelerated the reduction of Cr(VI) by sulfide. For example, the efficiency of Cr(VI) reduced by sulfide increased from 20.5% to 100% when jarosite (1g/L) was added to the homogenous reaction system at pH=8 within 40 min. The analysis of variance (ANOVA) revealed a high coefficient of determination (p-value<0.0001, R(2)=97.99%, Adj-R(2)=95.98%) between experimental Cr(VI) removal efficiency and predicted one by RSM developed model. The Pareto analysis results demonstrated that the pH of solution was the most significant term of the developed model. Operation temperature, loading of jarosite and reaction time exhibited synergistic effects on the reduction of Cr(VI), and the effect of interaction between independent factors on the response factor can't be ignored.
本文通过批实验和 X 射线光电子能谱（XPS）分析，研究了生物成因黄钾铁矾在硫化物还原 Cr(VI)中的促进作用及其机制。为研究操作参数对硫化物还原 Cr(VI)的影响，将溶液 pH、操作温度、黄钾铁矾负载量和反应时间四个操作参数作为响应面法（RSM）的输入变量。利用图形响应面和等高线图来评估操作参数之间相互作用对 Cr(VI)还原的影响。结果表明，黄钾铁矾表面发生了一个将 Fe(III)转化为 Fe(II)的循环过程，显著加速了硫化物还原 Cr(VI)的速度。例如，当在 pH=8 的均相反应体系中添加 1g/L 的黄钾铁矾时，硫化物还原 Cr(VI)的效率从 20.5%提高到 100%，在 40min 内完成。方差分析（ANOVA）表明，RSM 开发模型的实验 Cr(VI)去除效率与预测值之间具有很高的决定系数（p 值<0.0001，R(2)=97.99%，Adj-R(2)=95.98%）。Pareto 分析结果表明，溶液 pH 是该模型的最重要因素。操作温度、黄钾铁矾负载量和反应时间对 Cr(VI)的还原具有协同作用，独立因素之间的相互作用对响应因素的影响不容忽视。
