PMID- 33262427
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20201208
LR  - 20201214
IS  - 2045-2322 (Electronic)
IS  - 2045-2322 (Linking)
VI  - 10
IP  - 1
DP  - 2020 Dec 1
TI  - Understanding the biogeochemical mechanisms of metal removal from acid mine 
      drainage with a subsurface limestone bed at the Motokura Mine, Japan.
PG  - 20889
LID - 10.1038/s41598-020-78069-9 [doi]
LID - 20889
AB  - Subsurface limestone beds (SLBs) are used as a passive treatment technique to 
      remove toxic metals from acid mine drainage (AMD). In this study, we investigated 
      the mechanisms and thermodynamics of metal (manganese, copper, zinc, cadmium, and 
      lead) precipitation in the SLB installed at the Motokura Mine. Field surveys in 
      2017 and 2018 showed that the pH of the SLB influent (initially 5-6) increased to 
      approximately 8 in the drain between 24 and 45 m from the inlet. This increase 
      was caused by limestone dissolution and resulted in the precipitation of 
      hydroxides and/or carbonates of copper, zinc, and lead, as expected from 
      theoretical calculations. Manganese and cadmium were removed within a pH range of 
      approximately 7-8, which was lower than the pH at which they normally precipitate 
      as hydroxides (pH 9-10). X-ray absorption near-edge structure analysis of the 
      sediment indicated that delta-MnO(2), which has a high cation-exchange capacity, was 
      the predominant tetravalent manganese compound in the SLB rather than trivalent 
      compound (MnOOH). Biological analysis indicates that microorganism activity of 
      the manganese-oxidizing bacteria in the SLB provided an opportunity for delta-MnO(2) 
      formation, after which cadmium was removed by surface complexation with MnO(2) ( identical with 
      MnOH(0) + Cd(2+)  right arrow over left arrow   identical with MnOCd(+)  +  H(+)). These findings show that biological 
      agents contributed to the precipitation of manganese and cadmium in the SLB, and 
      suggest that their utilization could enhance the removal performance of the SLB.
FAU - Fuchida, Shigeshi
AU  - Fuchida S
AD  - Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, 
      Tokyo, 169-8555, Japan.
FAU - Suzuki, Kohei
AU  - Suzuki K
AD  - Graduate School of Creative Science and Engineering, Waseda University, 3-4-1 
      Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
FAU - Kato, Tatsuya
AU  - Kato T
AD  - Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, 
      Tokyo, 169-8555, Japan.
FAU - Kadokura, Masakazu
AU  - Kadokura M
AD  - Graduate School of Creative Science and Engineering, Waseda University, 3-4-1 
      Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
FAU - Tokoro, Chiharu
AU  - Tokoro C
AD  - Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, 
      Tokyo, 169-8555, Japan. tokoro@waseda.jp.
LA  - eng
PT  - Journal Article
DEP - 20201201
PL  - England
TA  - Sci Rep
JT  - Scientific reports
JID - 101563288
SB  - IM
PMC - PMC7708634
COIS- The authors declare no competing interests.
EDAT- 2020/12/03 06:00
MHDA- 2020/12/03 06:01
PMCR- 2020/12/01
CRDT- 2020/12/02 05:29
PHST- 2020/08/08 00:00 [received]
PHST- 2020/11/20 00:00 [accepted]
PHST- 2020/12/02 05:29 [entrez]
PHST- 2020/12/03 06:00 [pubmed]
PHST- 2020/12/03 06:01 [medline]
PHST- 2020/12/01 00:00 [pmc-release]
AID - 10.1038/s41598-020-78069-9 [pii]
AID - 78069 [pii]
AID - 10.1038/s41598-020-78069-9 [doi]
PST - epublish
SO  - Sci Rep. 2020 Dec 1;10(1):20889. doi: 10.1038/s41598-020-78069-9.