Identification of Green Rust in Groundwater

TY - JOUR

T1 - Identification of Green Rust in Groundwater

AU - Christiansen, Bo C.

AU - Balic Zunic, Tonci

AU - Dideriksen, Knud

AU - Stipp, Susan Louise Svane

PY - 2009

Y1 - 2009

N2 - Green rust, a family of Fe(II),Fe(III) layered double hydroxides, is believed to be present in environments close to the Fe(II)/Fe(III) transition zone. Attempts to identify members of this family in nature have proven difficult because the material is oxidized after only a few minutes exposure to air. In this paper, we present a sampling method for capturing green rust so it is not oxidized. We then we used the method to identify the compound in a groundwater sample taken below the water table from fractures in granite. X-ray diffraction patterns were weak, but clearly identical to those of synthetic GRCO3, the green rust familymemberwherecarbonate and water occupy the interlayer between the iron-hydroxide layers. The method was then tested on samples taken from an artesian well and a deep underground experimental station, both within the Fe(II)/Fe(III) redox zone. In both cases, GRCO3 could be identified. Currently, transport models for predicting the behavior of contaminants in groundwater do not include parameters for green rust. This work demonstrates they should.

AB - Green rust, a family of Fe(II),Fe(III) layered double hydroxides, is believed to be present in environments close to the Fe(II)/Fe(III) transition zone. Attempts to identify members of this family in nature have proven difficult because the material is oxidized after only a few minutes exposure to air. In this paper, we present a sampling method for capturing green rust so it is not oxidized. We then we used the method to identify the compound in a groundwater sample taken below the water table from fractures in granite. X-ray diffraction patterns were weak, but clearly identical to those of synthetic GRCO3, the green rust familymemberwherecarbonate and water occupy the interlayer between the iron-hydroxide layers. The method was then tested on samples taken from an artesian well and a deep underground experimental station, both within the Fe(II)/Fe(III) redox zone. In both cases, GRCO3 could be identified. Currently, transport models for predicting the behavior of contaminants in groundwater do not include parameters for green rust. This work demonstrates they should.

KW - Faculty of Science

U2 - 10.1021/es8011047

DO - 10.1021/es8011047

M3 - Journal article

SN - 0013-936X

VL - 43

SP - 3436

EP - 3441

JO - Environmental Science & Technology

JF - Environmental Science & Technology

IS - 10

ER -