Acta Chim. Sinica ›› 2017, Vol. 75 ›› Issue (6): 621-628.DOI: 10.6023/A17030093 Previous Articles     Next Articles

Special Issue: 铁环境化学



刘承帅a,b, 李芳柏a, 陈曼佳a, 廖长忠a, 童辉b, 华健a   

  1. a 广东省生态环境技术研究所 广东省农业环境综合治理重点实验室 广州 510650;
    b 中国科学院地球化学研究所 环境地球化学国家重点实验室 贵阳 550081
  • 投稿日期:2017-03-06 发布日期:2017-05-09
  • 通讯作者: 李芳柏
  • 基金资助:


Adsorption and Stabilization of Lead during Fe(II)-catalyzed Phase Transformation of Ferrihydrite

Liu Chengshuaia,b, Li Fangbaia, Chen Manjiaa, Liao Changzhonga, Tong Huib, Hua Jiana   

  1. a Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China;
    b State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
  • Received:2017-03-06 Published:2017-05-09
  • Contact: 10.6023/A17030093
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 41673135, 41420104007, 41671240), the Science and Technology Project of Guangdong Province (Nos. S2013050014266, 2015A030313752, 2016A030313780; 2016B020242006), and One Hundred Talents Programme of the Chinese Academy of Sciences.

Aqueous Fe(Ⅱ) (Fe(Ⅱ)aq)-catalyzed recrystallization of iron (hydr)oxides is the important chemical reaction of iron cycle in anaerobic environments, which poses significant effects on the environmental behavior of heavy metals in soils and sediments. Ferrihydrite is the initial iron mineral phase during the ferrous mineralization and has relatively unstable crystal structure. The structure transformation behavior of ferrihydrite is active and also poses important effects on environmental behavior of soil heavy metals. However, the Fe(Ⅱ)aq-catalyzed phase transformation of ferrihydrite has been rarely reported, especially with the coexisting metal ions. In the present study, the effects of coexisting heavy metal of Pb(Ⅱ) on the Fe(Ⅱ)aq-catalyzed phase transformation of ferrihydrite coupling the environmental behavior of Pb(Ⅱ) were systematically studied. The results show that ferrihydrite underwent efficient phase transformation rates when catalyzed by Fe(Ⅱ)aq whenever with or without the effect of Pb(Ⅱ). Compared with the reaction system that without Pb(Ⅱ), the adsorption of Fe(Ⅱ) on the surface of ferrihydrite was inhibited due to the competition of Pb(Ⅱ) when with the coexistence of Pb(Ⅱ), which further decreased the rates of Fe atom exchange between Fe(Ⅱ)aq and structural Fe(Ⅲ) of ferrihydrite. With the inhibited Fe atom exchange reaction, the phase transformation rates were relatively decreased and transformation products were changed during the Fe(Ⅱ)aq-catalyzed phase transformation of ferrihydrite. Goethite and magnetite were found to be the final transformed products of iron (hydr)oxides when without Pb(Ⅱ), while lepidocrocite was determined to be the main transformed product with little goethite and magnetite as the other transformed products when with Pb(Ⅱ). During the Fe(Ⅱ)aq-catalyzed phase transformation of ferrihydrite with the coexistence of Pb(Ⅱ), some Pb were stabilized through being incorporated into the structure of ferrihydrite transformed products with the possible mechanisms of occlusion by the crystal lattice and structural incorporation, so as to decrease the activity of the polluted heavy metal of Pb. The obtained results in the present study are expected to provide further insights for understanding the iron cycle coupling with the environmental behavior of heavy metals in soils and sediments.

Key words: iron oxide, Fe atom exchange, heavy metal, stable isotope tracing, isomorphous replacement