Abstract
Fe-rich smectite is ubiquitous in soil environments and closely linked to the fate and mobility of hazardous trace metals and particularly to the variations in the biogeochemical redox reactions of structural Fe that determine the sorption and desorption properties of clay minerals. The biotic/abiotic redox reactions of a Fe-rich smectite, nontronite (NAu-1), were performed at various reaction times using the Fe-reducing bacterium Shewanella oneidensis MR-1 at 30ºC and Na-dithionite (Na2S2O4), respectively. The extent of biotic Fe-reduction of NAu-1 after 30 days of incubation reached up to 10.7% of total Fe and the range of abiotic Fe-reduction varied from 4.9 46.6% at reaction times of 5 min, 30 min, 1 h, and 4 h. The biotically and abiotically Fe-reduced NAu-1 samples were spiked with Pb concentrations of 0.07, 0.2, 0.5, and 1.0 mg/kg and incubated under aerobic or anaerobic conditions for 24 h. The amounts of Pb in the supernatants were analyzed using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Multi-collector (MC)-ICP-MS. The amounts of Pb removed from the supernatants were negatively related to the extent of Fe(III) reduction in the abiotically Fe-reduced NAu-1 samples. In contrast, less Pb (~15%) was removed from the biotically Fe-reduced NAu-1 samples with a similar extent of Fe(III) reduction. Changes in the isotopic208/204Pb ratio indicated that the lighter204Pb isotope was preferentially adsorbed to the NAu-1 samples with less Fe reduction and indicated that variations in the net layer charge affected isotopic fractionation. Significant differences in the208/204Pb ratios for NAu-1 samples that were biotically Fe-reduced under anaerobic conditions were measured and indicate that the reversibility of the structural/chemical modifications that occur under redox conditions can affect Pb removal and, thus, isotope fractionation. These results collectively infer that the biogeochemical properties of clay minerals should be considered in order to understand the fate of trace metals in natural environments.
| Original language | English |
|---|---|
| Pages (from-to) | 410-416 |
| Number of pages | 7 |
| Journal | Clays and Clay Minerals |
| Volume | 65 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2017 Dec |
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All Science Journal Classification (ASJC) codes
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
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The effects of biogeochemical modification of Fe-rich smectite on the fate of pb. / Koo, Tae Hee; Kim, Jee Young; Choi, Jong Woo; Kim, Jin Wook.
In: Clays and Clay Minerals, Vol. 65, No. 6, 12.2017, p. 410-416.Research output: Contribution to journal › Article
TY - JOUR
T1 - The effects of biogeochemical modification of Fe-rich smectite on the fate of pb
AU - Koo, Tae Hee
AU - Kim, Jee Young
AU - Choi, Jong Woo
AU - Kim, Jin Wook
PY - 2017/12
Y1 - 2017/12
N2 - Fe-rich smectite is ubiquitous in soil environments and closely linked to the fate and mobility of hazardous trace metals and particularly to the variations in the biogeochemical redox reactions of structural Fe that determine the sorption and desorption properties of clay minerals. The biotic/abiotic redox reactions of a Fe-rich smectite, nontronite (NAu-1), were performed at various reaction times using the Fe-reducing bacterium Shewanella oneidensis MR-1 at 30ºC and Na-dithionite (Na2S2O4), respectively. The extent of biotic Fe-reduction of NAu-1 after 30 days of incubation reached up to 10.7% of total Fe and the range of abiotic Fe-reduction varied from 4.9 46.6% at reaction times of 5 min, 30 min, 1 h, and 4 h. The biotically and abiotically Fe-reduced NAu-1 samples were spiked with Pb concentrations of 0.07, 0.2, 0.5, and 1.0 mg/kg and incubated under aerobic or anaerobic conditions for 24 h. The amounts of Pb in the supernatants were analyzed using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Multi-collector (MC)-ICP-MS. The amounts of Pb removed from the supernatants were negatively related to the extent of Fe(III) reduction in the abiotically Fe-reduced NAu-1 samples. In contrast, less Pb (~15%) was removed from the biotically Fe-reduced NAu-1 samples with a similar extent of Fe(III) reduction. Changes in the isotopic208/204Pb ratio indicated that the lighter204Pb isotope was preferentially adsorbed to the NAu-1 samples with less Fe reduction and indicated that variations in the net layer charge affected isotopic fractionation. Significant differences in the208/204Pb ratios for NAu-1 samples that were biotically Fe-reduced under anaerobic conditions were measured and indicate that the reversibility of the structural/chemical modifications that occur under redox conditions can affect Pb removal and, thus, isotope fractionation. These results collectively infer that the biogeochemical properties of clay minerals should be considered in order to understand the fate of trace metals in natural environments.
AB - Fe-rich smectite is ubiquitous in soil environments and closely linked to the fate and mobility of hazardous trace metals and particularly to the variations in the biogeochemical redox reactions of structural Fe that determine the sorption and desorption properties of clay minerals. The biotic/abiotic redox reactions of a Fe-rich smectite, nontronite (NAu-1), were performed at various reaction times using the Fe-reducing bacterium Shewanella oneidensis MR-1 at 30ºC and Na-dithionite (Na2S2O4), respectively. The extent of biotic Fe-reduction of NAu-1 after 30 days of incubation reached up to 10.7% of total Fe and the range of abiotic Fe-reduction varied from 4.9 46.6% at reaction times of 5 min, 30 min, 1 h, and 4 h. The biotically and abiotically Fe-reduced NAu-1 samples were spiked with Pb concentrations of 0.07, 0.2, 0.5, and 1.0 mg/kg and incubated under aerobic or anaerobic conditions for 24 h. The amounts of Pb in the supernatants were analyzed using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Multi-collector (MC)-ICP-MS. The amounts of Pb removed from the supernatants were negatively related to the extent of Fe(III) reduction in the abiotically Fe-reduced NAu-1 samples. In contrast, less Pb (~15%) was removed from the biotically Fe-reduced NAu-1 samples with a similar extent of Fe(III) reduction. Changes in the isotopic208/204Pb ratio indicated that the lighter204Pb isotope was preferentially adsorbed to the NAu-1 samples with less Fe reduction and indicated that variations in the net layer charge affected isotopic fractionation. Significant differences in the208/204Pb ratios for NAu-1 samples that were biotically Fe-reduced under anaerobic conditions were measured and indicate that the reversibility of the structural/chemical modifications that occur under redox conditions can affect Pb removal and, thus, isotope fractionation. These results collectively infer that the biogeochemical properties of clay minerals should be considered in order to understand the fate of trace metals in natural environments.
UR - http://www.scopus.com/inward/record.url?scp=85041698238&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85041698238&partnerID=8YFLogxK
U2 - 10.1346/CCMN.2017.064080
DO - 10.1346/CCMN.2017.064080
M3 - Article
AN - SCOPUS:85041698238
VL - 65
SP - 410
EP - 416
JO - Clays and Clay Minerals
JF - Clays and Clay Minerals
SN - 0009-8604
IS - 6
ER -