| 铁屑-微生物协同还原去除水体中Cr(Ⅵ)研究 |
| 摘要点击 3271 全文点击 1740 投稿时间：2012-10-06 修订日期：2012-12-10 |
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| 中文关键词 铁屑 微生物 Cr(Ⅵ) 影响因素 XPS |
| 英文关键词 iron filings microorganism Cr(Ⅵ) influencing factors XPS |
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| 中文摘要 |
| 考察了铁屑和微生物对受污染水体中Cr(Ⅵ)的还原去除能力以及Cr(Ⅵ)去除效率的影响因素,分析了反应后铁屑表面的组成以及Cr(Ⅵ)还原产物的形态特征. 结果表明,铁屑-微生物协同处理对水体Cr(Ⅵ)的去除具有促进作用,在18 h内Cr(Ⅵ)去除率就可达到100%. 在25~42℃范围内,温度升高有利于Cr(Ⅵ)的去除; Cr(Ⅵ)还原去除的最适宜初始pH为5.8. Cr(Ⅵ)去除效率随着铁屑投加量和微生物接种量的增大而增大,随着Cr(Ⅵ)初始浓度的增大而减小. Mn2+、Zn2+、Co2+、Cu2+和Ni2+离子对Cr(Ⅵ)的还原去除都有一定的抑制作用,其中Mn2+的影响最小,Ni2+的抑制作用最为明显. XPS分析结果显示,铁屑表面吸附和沉积了Cr元素,且有Cr(Ⅲ)和Cr(Ⅵ)两种价态; Cr2p3/2轨道处的出峰由Cr(Ⅲ)在(576.8±0.1)eV处的峰和Cr(Ⅵ)在(578.1±0.1)eV处的峰叠加而成,还原产物Cr(Ⅲ)极有可能以Cr(OH)3以及铁铬氧化水合物[FexCr1-x(OH)3]形式存在. |
| 英文摘要 |
| The reduction of Cr(Ⅵ) by iron filings and microorganisms was carried out during our investigation. Effects of factors (e. g. temperature, initial pH, iron filings loadings, inoculum size, initial concentration of Cr(Ⅵ) and other ions) on Cr(Ⅵ) reduction were studied, and the X-ray photoelectron spectroscopy (XPS) was applied to explore elements composition on the surface of iron filings. Experimental results revealed a promotion of Cr(Ⅵ) reduction by iron filings with the presence of microorganisms, and the Cr(Ⅵ) removal was complete within 18 h. Results showed the Cr(Ⅵ) reduction preferred a higher temperature within the range of 25-42℃ and the optimum initial pH was supposed to be 5.8. The efficiency of Cr(Ⅵ) reduction was increased with increasing amounts of iron filings and microorganisms, and was decreased with the increasing initial concentration of Cr(Ⅵ). Mn2+、Zn2+、Co2+、Cu2+ and Ni2+ ions could cause varying degrees of inhibition of Cr(Ⅵ) reduction, and among these ions, the effect of Mn2+ was the smallest and that of Ni2+ was the highest. Characterizations with XPS indicated the deposition of Cr element on iron filings surface in forms of Cr(Ⅲ) and Cr(Ⅵ), as the Cr2p3/2 region could be decomposed into two peaks at (576.8±0.1)eV and (578.1±0.1)eV. Furthermore, Cr(Ⅲ) was most likely to be in the form of Cr(OH)3 or Fe xCr1-x(OH)3. |
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