Effect of Ni2+, Zn2+, and Co2+ on green rust transformation to magnetite

Geochemical Transactions

Research

Evert J. Elzinga¹  Orion Farr²  Nathan Yee³ 

[1]Department of Earth and Environmental Sciences, Rutgers University−Newark, 07102, Newark, NJ, USA

[2]Department of Earth and Planetary Sciences, Rutgers University, 08854, Piscataway, NJ, USA

[3]Department of Earth and Planetary Sciences, Rutgers University, 08854, Piscataway, NJ, USA

[4]Department of Environmental Sciences, Rutgers University, 08901, New Brunswick, NJ, USA

关键词: Hydrosulfate green rust;    Layered double hydroxides;    Adsorption;    Banded iron formations;    Archean;    Seawater;    Nutrients;    Diagenesis;   

DOI  :  10.1186/s12932-022-00080-y

 received in 2022-10-16, accepted in 2022-12-10,  发布年份 2022

来源: Springer

【 摘 要 】

In this study, we investigated Ni2+, Zn2+, and Co2+ mineralogical incorporation and its effect on green rust transformation to magnetite. Mineral transformation experiments were conducted by heating green rust suspensions at 85 °C in the presence of Ni2+, Zn2+, or Co2+ under strict anoxic conditions. Transmission electron microscopy and powder X-ray diffraction showed the conversion of hexagonal green rust platelets to fine grained cubic magnetite crystals. The addition of Ni2+, Zn2+, and Co2+ resulted in faster rates of mineral transformation. The conversion of green rust to magnetite was concurrent to significant increases in metal uptake, demonstrating a strong affinity for metal sorption/co-precipitation by magnetite. Dissolution ratio curves showed that Ni2+, Zn2+, and Co2+ cations were incorporated into the mineral structure during magnetite crystal growth. The results indicate that the transformation of green rust to magnetite is accelerated by metal impurities, and that magnetite is a highly effective scavenger of trace metals during mineral transformation. The implications for using diagenetic magnetite from green rust precursors as paleo-proxies of Precambrian ocean chemistry are discussed.Graphical Abstract

【 授权许可】

CC BY   
© The Author(s) 2022

【 图 表 】

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