Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron

Ann Kambhu, Megan Gren, Wei Tang, Steve Comfort, Clifford E. Harris

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe 0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe 0 -activated persulfate was used to treat dioxane. Treatment variables included the timing at which the dioxane was added to the Fe 0 -persulfate reaction (T = 0 and 30 min) and including various products of the Fe 0 -persulfate reaction at T = 0 min (Fe 2+ , Fe 3+ , and SO 4 2− ). Results showed that when dioxane was spiked into the reaction at 30 min, no degradation occurred; this is in stark contrast to the 60% decrease observed when added at T = 0 min. Adding Fe 2+ at the onset (T = 0 min) also severely halted the reaction and caused a plateau. This indicates that excess ferrous iron produced from the Fe 0 -persulfate reaction scavenges sulfate radicals and prevents further dioxane degradation. By limiting the release of Fe 0 in a slow-release wax formulation, degradation plateaus were avoided and 100% removal of dioxane observed. By using 14 C-labeled dioxane, we show that ∼40% of the dioxane carbon is mineralized within 6 d. These data support the use of slow-release persulfate and zerovalent iron to treat dioxane-contaminated water.

Original languageEnglish (US)
Pages (from-to)170-177
Number of pages8
JournalChemosphere
Volume175
DOIs
StatePublished - Jan 1 2017

Fingerprint

Iron
plateau
iron
Degradation
degradation
Water
water
Waxes
Corrosion inhibitors
reaction kinetics
wax
Reaction kinetics
Sodium
sodium
Impurities
sulfate
Carbon
1,4-dioxane
pollutant
metal

Keywords

  • Chlorinated solvents
  • Dioxane
  • Persulfate
  • Slow-release oxidants
  • TCE

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

Cite this

Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron. / Kambhu, Ann; Gren, Megan; Tang, Wei; Comfort, Steve; Harris, Clifford E.

In: Chemosphere, Vol. 175, 01.01.2017, p. 170-177.

Research output: Contribution to journalArticle

Kambhu, Ann ; Gren, Megan ; Tang, Wei ; Comfort, Steve ; Harris, Clifford E. / Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron. In: Chemosphere. 2017 ; Vol. 175. pp. 170-177.
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abstract = "1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe 0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe 0 -activated persulfate was used to treat dioxane. Treatment variables included the timing at which the dioxane was added to the Fe 0 -persulfate reaction (T = 0 and 30 min) and including various products of the Fe 0 -persulfate reaction at T = 0 min (Fe 2+ , Fe 3+ , and SO 4 2− ). Results showed that when dioxane was spiked into the reaction at 30 min, no degradation occurred; this is in stark contrast to the 60{\%} decrease observed when added at T = 0 min. Adding Fe 2+ at the onset (T = 0 min) also severely halted the reaction and caused a plateau. This indicates that excess ferrous iron produced from the Fe 0 -persulfate reaction scavenges sulfate radicals and prevents further dioxane degradation. By limiting the release of Fe 0 in a slow-release wax formulation, degradation plateaus were avoided and 100{\%} removal of dioxane observed. By using 14 C-labeled dioxane, we show that ∼40{\%} of the dioxane carbon is mineralized within 6 d. These data support the use of slow-release persulfate and zerovalent iron to treat dioxane-contaminated water.",
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AU - Harris, Clifford E.

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N2 - 1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe 0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe 0 -activated persulfate was used to treat dioxane. Treatment variables included the timing at which the dioxane was added to the Fe 0 -persulfate reaction (T = 0 and 30 min) and including various products of the Fe 0 -persulfate reaction at T = 0 min (Fe 2+ , Fe 3+ , and SO 4 2− ). Results showed that when dioxane was spiked into the reaction at 30 min, no degradation occurred; this is in stark contrast to the 60% decrease observed when added at T = 0 min. Adding Fe 2+ at the onset (T = 0 min) also severely halted the reaction and caused a plateau. This indicates that excess ferrous iron produced from the Fe 0 -persulfate reaction scavenges sulfate radicals and prevents further dioxane degradation. By limiting the release of Fe 0 in a slow-release wax formulation, degradation plateaus were avoided and 100% removal of dioxane observed. By using 14 C-labeled dioxane, we show that ∼40% of the dioxane carbon is mineralized within 6 d. These data support the use of slow-release persulfate and zerovalent iron to treat dioxane-contaminated water.

AB - 1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe 0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe 0 -activated persulfate was used to treat dioxane. Treatment variables included the timing at which the dioxane was added to the Fe 0 -persulfate reaction (T = 0 and 30 min) and including various products of the Fe 0 -persulfate reaction at T = 0 min (Fe 2+ , Fe 3+ , and SO 4 2− ). Results showed that when dioxane was spiked into the reaction at 30 min, no degradation occurred; this is in stark contrast to the 60% decrease observed when added at T = 0 min. Adding Fe 2+ at the onset (T = 0 min) also severely halted the reaction and caused a plateau. This indicates that excess ferrous iron produced from the Fe 0 -persulfate reaction scavenges sulfate radicals and prevents further dioxane degradation. By limiting the release of Fe 0 in a slow-release wax formulation, degradation plateaus were avoided and 100% removal of dioxane observed. By using 14 C-labeled dioxane, we show that ∼40% of the dioxane carbon is mineralized within 6 d. These data support the use of slow-release persulfate and zerovalent iron to treat dioxane-contaminated water.

KW - Chlorinated solvents

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