Thiosulfate driving bio-reduction mechanisms of scorodite in groundwater environment

Reductive dissolution of scorodite results in the release and migration of arsenic (As) in groundwater. The purpose of this study was to explore the possible abiotic and biotic reduction of scorodite in groundwater environment and the effect of microbial-mediated sulfur cycling on the bio-reduction...

Full description

Saved in:
Bibliographic Details
Published in:Chemosphere (Oxford) 2023-01, Vol.311, p.136956-136956, Article 136956
Main Authors: Yang, Yang, Xie, Zuoming, Wang, Jia, Chen, Mengna
Format: Article
Language:English
Subjects:
Bio-reduction of As/Fe
Groundwater
Parasymplesite
Release of As
Scorodite
Thiosulfate
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Reductive dissolution of scorodite results in the release and migration of arsenic (As) in groundwater. The purpose of this study was to explore the possible abiotic and biotic reduction of scorodite in groundwater environment and the effect of microbial-mediated sulfur cycling on the bio-reduction of scorodite. Microcosm experiments consisting of scorodite with bacterium Citrobacter sp. JH012-1 or free sulfide were carried out to determine the effects of thiosulfate on the mobilization of As/Fe. The results show arsenic release is positively correlated with iron reduction. The arsenate [As(V)] released can agglomerate with Fe(II) on the surface of scorodite to form crystalline parasymplesite, while no parasymplesite was detected in the abiotic reduction of scorodite by sulfide. The reduction of scorodite and As(V) was affected by thiosulfate. When 0.5 mM thiosulfate was added, the Fe(III) reduction rate increased from 32% to 82%, and the As(V) reduction rate rose from 54% to 64%. When the addition of thiosulfate was increased from 0.5 mM to 2 mM and 5 mM, Fe(III) reduction rate added 4% and 8%, and As(V) reduction rate increased 11% and 16%, respectively. In addition, the presence of thiosulfate promoted the scorodite almost completely converting to parasymplesite. Therefore, the effect of microbial-mediated sulfur cycling should be considered in arsenic migration and reduction from scorodite. [Display omitted] •The release of arsenic was positively correlated with the reduction of scorodite.•Parasymplesite was the main product of scorodite bio-reduction.•Thiosulfate promoted the bio-reduction of scorodite.•The formation of parasymplesite was affected by thiosulfate.
ISSN:0045-6535
1879-1298
DOI:10.1016/j.chemosphere.2022.136956