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Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion.
Chemosphere. 2004 Jun; 55(9):1225-33.C

Abstract

In situ chemical oxidation (ISCO) is a technique used to remediate contaminated soil and groundwater systems. It has been postulated that sodium persulfate (Na2S2O8) can be activated by transition metal ions such as ferrous ion (Fe2+) to produce a powerful oxidant known as the sulfate free radical (SO4-*) with a redox potential of 2.6 V, which can potentially destroy organic contaminants. In this laboratory study persulfate oxidation of dissolved trichloroethylene (TCE) was investigated in aqueous and soil slurry systems under a variety of experimental conditions. A chelating agent (i.e., citric acid) was used in attempt to manipulate the quantity of ferrous ion in solution by providing an appropriate chelate/Fe2+ molar ratio. In an aqueous system a chelate/Fe2+ molar ratio of 1/5 (e.g., S2O8(2)-/chelate/Fe2+/TCE ratio of 20/2/10/1) was found to be the lowest acceptable ratio to maintain sufficient quantities of Fe2+ activator in solution resulting in nearly complete TCE destruction after only 20 min. The availability of Fe2+ appeared to be controlled by adjusting the molar ratio of chelate/Fe2+. In general, high levels of chelated ferrous ion concentrations resulted in faster TCE degradation and more persulfate decomposition. However, if initial ferrous ion contents are relatively low, sufficient quantities of chelate must be provided to ensure the chelation of a greater percentage of the limited ferrous ion present. Citric acid chelated ferrous ion appeared effective for TCE degradation within soil slurries but required longer reaction times. Additionally, the use of citric acid without the addition of supplemental Fe2+ in soil slurries, where the citric acid apparently extracted native metals from the soil, appeared to be somewhat effective at enhancing persulfate oxidation of TCE over extended reaction times. A comparison of different chelating agents revealed that citric acid was the most effective.

Authors+Show Affiliations

Department of Civil and Environmental Engineering, University of Massachusetts, One University Avenue, Lowell, MA 01854, USA. chenju_liang@uml.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

15081763

Citation

Liang, Chenju, et al. "Persulfate Oxidation for in Situ Remediation of TCE. II. Activated By Chelated Ferrous Ion." Chemosphere, vol. 55, no. 9, 2004, pp. 1225-33.
Liang C, Bruell CJ, Marley MC, et al. Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion. Chemosphere. 2004;55(9):1225-33.
Liang, C., Bruell, C. J., Marley, M. C., & Sperry, K. L. (2004). Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion. Chemosphere, 55(9), 1225-33.
Liang C, et al. Persulfate Oxidation for in Situ Remediation of TCE. II. Activated By Chelated Ferrous Ion. Chemosphere. 2004;55(9):1225-33. PubMed PMID: 15081763.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion. AU - Liang,Chenju, AU - Bruell,Clifford J, AU - Marley,Michael C, AU - Sperry,Kenneth L, PY - 2003/05/16/received PY - 2003/11/13/revised PY - 2004/01/15/accepted PY - 2004/4/15/pubmed PY - 2004/6/30/medline PY - 2004/4/15/entrez SP - 1225 EP - 33 JF - Chemosphere JO - Chemosphere VL - 55 IS - 9 N2 - In situ chemical oxidation (ISCO) is a technique used to remediate contaminated soil and groundwater systems. It has been postulated that sodium persulfate (Na2S2O8) can be activated by transition metal ions such as ferrous ion (Fe2+) to produce a powerful oxidant known as the sulfate free radical (SO4-*) with a redox potential of 2.6 V, which can potentially destroy organic contaminants. In this laboratory study persulfate oxidation of dissolved trichloroethylene (TCE) was investigated in aqueous and soil slurry systems under a variety of experimental conditions. A chelating agent (i.e., citric acid) was used in attempt to manipulate the quantity of ferrous ion in solution by providing an appropriate chelate/Fe2+ molar ratio. In an aqueous system a chelate/Fe2+ molar ratio of 1/5 (e.g., S2O8(2)-/chelate/Fe2+/TCE ratio of 20/2/10/1) was found to be the lowest acceptable ratio to maintain sufficient quantities of Fe2+ activator in solution resulting in nearly complete TCE destruction after only 20 min. The availability of Fe2+ appeared to be controlled by adjusting the molar ratio of chelate/Fe2+. In general, high levels of chelated ferrous ion concentrations resulted in faster TCE degradation and more persulfate decomposition. However, if initial ferrous ion contents are relatively low, sufficient quantities of chelate must be provided to ensure the chelation of a greater percentage of the limited ferrous ion present. Citric acid chelated ferrous ion appeared effective for TCE degradation within soil slurries but required longer reaction times. Additionally, the use of citric acid without the addition of supplemental Fe2+ in soil slurries, where the citric acid apparently extracted native metals from the soil, appeared to be somewhat effective at enhancing persulfate oxidation of TCE over extended reaction times. A comparison of different chelating agents revealed that citric acid was the most effective. SN - 0045-6535 UR - https://www.unboundmedicine.com/medline/citation/15081763/Persulfate_oxidation_for_in_situ_remediation_of_TCE__II__Activated_by_chelated_ferrous_ion_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(04)00067-0 DB - PRIME DP - Unbound Medicine ER -