Cheng Rong, Xue Xingyan, Shi Lei, Zhang Tao, Liu Yaping, Kang Mi, Zheng Xiang
School of Environment & Natural Resources, Renmin University of China, No. 59 Zhongguancun Street, Haidian District, Beijing 100872, China E-mail:
Water Sci Technol. 2017 Jan;75(2):263-270. doi: 10.2166/wst.2016.505.
Fe nanoparticles have been widely studied for pollution abatement in recent years; however, regarding the mechanism for pollutant degradation, studies have mainly focused on the reductive dechlorination by Fe, and the dynamic process has not been clarified completely. As reported, some organics could be degraded during the oxidation of Fe by O, and hydrogen peroxide was supposed to be produced. In this study, FeO, an oxidation product of Fe, was used to treat the pollutant combining with Fe nanoparticles, and 4-chlorophenol (4-CP) was used as the model pollutant. The results showed that the addition of FeO nanoparticles hindered the removal of 4-CP by Fe nanoparticles under anoxic conditions. However, the dechlorination efficiency was improved in the initial 6 h. Under aerobic conditions, the reused FeO nanoparticles would improve the removal and dechlorination of 4-CP. Especially, the dechlorination efficiency was obviously increased. It is proposed that the removal of 4-CP was due to the effects of both nanosized Fe and FeO - reducing action of Fe and catalytic oxidation action of FeO. The reducing action of Fe was the major factor under anoxic conditions. And the catalytic oxidation action of FeO became an important reason under aerobic conditions.
近年来，铁纳米颗粒在污染治理方面得到了广泛研究；然而，关于污染物降解的机制，研究主要集中在铁的还原脱氯作用上，其动态过程尚未完全阐明。据报道，一些有机物在铁被氧气氧化的过程中可能会降解，并且推测会产生过氧化氢。在本研究中，铁的氧化产物FeO与铁纳米颗粒结合用于处理污染物，4-氯苯酚（4-CP）被用作模型污染物。结果表明，在缺氧条件下，添加FeO纳米颗粒会阻碍铁纳米颗粒对4-CP的去除。然而，在最初的6小时内脱氯效率有所提高。在有氧条件下，重复使用的FeO纳米颗粒会提高4-CP的去除和脱氯效果。特别是，脱氯效率明显提高。研究表明，4-CP的去除归因于纳米铁和FeO的共同作用——铁的还原作用和FeO的催化氧化作用。在缺氧条件下，铁的还原作用是主要因素。而在有氧条件下，FeO的催化氧化作用成为一个重要原因。
