Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions

Lucia Rodriguez-Freire, Maria Reye Sierra Alvarez, Robert Root, Jon Chorover, James A Field

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42-). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42- and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions.

Original languageEnglish (US)
Pages (from-to)242-253
Number of pages12
JournalWater Research
Volume66
DOIs
StatePublished - Dec 1 2014

Fingerprint

Biomineralization
biomineralization
arsenate
Arsenic
arsenic
sulfide
Sulfide minerals
Sulfides
Precipitates
ethanol
Ethanol
mineral
spectroscopy
Spectroscopy
realgar
fold
adsorption
Adsorption
X rays
Biofilms

Keywords

  • Arsenate reduction
  • Biomineralization
  • Bioprecipitation
  • Orpiment
  • Realgar
  • Sulfate reduction

ASJC Scopus subject areas

  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Ecological Modeling

Cite this

Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions. / Rodriguez-Freire, Lucia; Sierra Alvarez, Maria Reye; Root, Robert; Chorover, Jon; Field, James A.

In: Water Research, Vol. 66, 01.12.2014, p. 242-253.

Research output: Contribution to journalArticle

@article{297e90d50f2840d89fe3cc7ea360c87b,
title = "Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions",
abstract = "Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42-). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42- and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions.",
keywords = "Arsenate reduction, Biomineralization, Bioprecipitation, Orpiment, Realgar, Sulfate reduction",
author = "Lucia Rodriguez-Freire and {Sierra Alvarez}, {Maria Reye} and Robert Root and Jon Chorover and Field, {James A}",
year = "2014",
month = "12",
day = "1",
doi = "10.1016/j.watres.2014.08.016",
language = "English (US)",
volume = "66",
pages = "242--253",
journal = "Water Research",
issn = "0043-1354",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions

AU - Rodriguez-Freire, Lucia

AU - Sierra Alvarez, Maria Reye

AU - Root, Robert

AU - Chorover, Jon

AU - Field, James A

PY - 2014/12/1

Y1 - 2014/12/1

N2 - Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42-). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42- and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions.

AB - Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42-). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42- and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions.

KW - Arsenate reduction

KW - Biomineralization

KW - Bioprecipitation

KW - Orpiment

KW - Realgar

KW - Sulfate reduction

UR - http://www.scopus.com/inward/record.url?scp=84907735721&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84907735721&partnerID=8YFLogxK

U2 - 10.1016/j.watres.2014.08.016

DO - 10.1016/j.watres.2014.08.016

M3 - Article

C2 - 25222328

AN - SCOPUS:84907735721

VL - 66

SP - 242

EP - 253

JO - Water Research

JF - Water Research

SN - 0043-1354

ER -