School of Civil Engineering and Environmental Science, University of Oklahoma , Norman, Oklahoma 73019, United States.
Environ Sci Technol. 2016 Jun 7;50(11):5489-97. doi: 10.1021/acs.est.5b06154. Epub 2016 May 11.
This paper investigated the mackinawite (FeS)-associated products formed during reaction between FeS and carbon tetrachloride (CT) at pH 7 and 8. At pH 8, reaction of FeS with CT led to formation of abundant spherical particles with diameters between 50 and 400 nm on the FeS surface and in solution; far fewer such particles were observed at pH 7. Analysis of the FeS surface by energy dispersive X-ray spectroscopy after reaction with CT at pH 8 showed decreased sulfur and elevated oxygen compared to unreacted FeS. The spherical particles that formed upon FeS reaction with CT were mostly amorphous with localized areas of poorly crystalline two-line ferrihydrite. X-ray photoelectron spectroscopy indicated that the predominant Fe surface species after reaction with CT at pH 8 was Fe(III)-O, consistent with ferrihydrite and other amorphous iron (hydr)oxides as major products. Powder X-ray diffraction analysis suggested formation of greigite upon reaction of FeS with CT at pH 7. Both ferrihydrite and Fe(2+), which is a product of greigite dissolution, can react with dissolved HS(-) to form FeS, suggesting that, after oxidation by chlorinated aliphatics, FeS can be regenerated by addition or microbial generation of sulfide.
本文研究了 pH 值为 7 和 8 时，FeS 与四氯化碳（CT）反应生成的磁黄铁矿（FeS）相关产物。在 pH 值为 8 时，FeS 与 CT 反应在 FeS 表面和溶液中形成了大量直径在 50 至 400nm 之间的球形颗粒；在 pH 值为 7 时，观察到的此类颗粒要少得多。在 pH 值为 8 时与 CT 反应后，用能量色散 X 射线光谱法分析 FeS 表面，与未反应的 FeS 相比，硫含量降低，氧含量升高。FeS 与 CT 反应形成的球形颗粒主要为无定形，局部区域为结晶不良的两线水铁矿。X 射线光电子能谱表明，在 pH 值为 8 时与 CT 反应后，Fe 表面的主要物种为 Fe(III)-O，与水铁矿和其他无定形铁（氢）氧化物为主要产物一致。粉末 X 射线衍射分析表明，在 pH 值为 7 时，FeS 与 CT 反应生成了陨硫铁。水铁矿和作为陨硫铁溶解产物的 Fe(2+)都可以与溶解的 HS(-)反应生成 FeS，这表明，在被氯化脂肪族化合物氧化后，通过添加或微生物产生的硫化物，FeS 可以被再生。
