The roles of pyrite for enhancing reductive removal of nitrobenzene by zero-valent iron
The roles of pyrite for enhancing reductive removal of nitrobenzene by zero-valent iron
复制标题
黄铁矿增强零价铁还原去除硝基苯的作用
DOI：
10.1016/j.apcatb.2018.09.086
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发表时间：
2019-03-01
影响因子：
22.1
通讯作者：
Guan, Xiaohong
中科院分区：
文献类型：
--
作者：
Lu, Ying;Li, Jianfa;Guan, Xiaohong
Zero-valent iron (ZVI) is a popular reductant that has been successfully applied for remediation of groundwater contaminated with various pollutants, but it still suffers from surface passivation and pH increase in the reaction media. In this study, pyrite, a ubiquitous sulfide mineral in anaerobic environment, was adopted to enhance the reactivity of ZVI for removal of nitrobenzene. The synergetic effect between pyrite and ZVI was observed for nitrobenzene reduction, and the rate constant k(obs) at the initial pH (pH(o)) 6.0 was enhanced by 8.55-23.1 folds due to the presence of pyrite with pyrite/ZVI mass ratio ranging from 1.0 to 6.0. Moreover, nitrobenzene could be removed effectively at pHo ranging from 5.0 to 10.0 in the presence of pyrite, while negligible removal of nitrobenzene by ZVI (0.5 g/L) alone was observed at pH(o) >= 7.0. ZVI sample recovered from the reacted ZVI/pyrite mixture was also more effective for nitrobenzene degradation than pristine ZVI. The mechanism study revealed that pyrite could suppress the pH increase in reaction media, boost the production of reactive Fe2+, and activate the ZVI surface through replacing partially the passive oxide film with iron sulfide (FeS). In particular, the formation of highly reactive FeS@Fe in the reaction system of ZVI/pyrite mixture was proved by XRD, Mossbauer,}CANES, XPS and SEM-EDS analyses, which provides a facile way for in-situ sulfidation of ZVI and for enhancing the removal of contaminants with ZVI technology.
