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Oxidation of sulfonamide antimicrobials by ferrate(VI) [Fe(VI)O4(2-)].
Environ Sci Technol. 2006 Dec 01; 40(23):7222-7.ES

Abstract

Sulfonamide antimicrobials are used in both human therapy and animal husbandry. Sulfonamides are not readily biodegradable and have been detected in surface water and in secondary wastewater effluents. The chemical oxidation of sulfonamides by an environmentally friendly oxidant, ferrate(VI) (Fe(VI)O4(2-), Fe(VI)), was conducted. The sulfonamides used in the oxidation studies were sulfisoxazole, sulfamethazine, sulfamethizole, sulfadimethoxine, and sulfamethoxazole. Kinetics of the reactions were determined as a function of pH (7.0-9.7) and temperature (15-45 degrees C) by a stopped-flow technique. The rate law for the oxidation of sulfonamides by Fe(VI) is first-order with respect to each reactant. The observed second-order rate constants decreased nonlinearly with an increase in pH and are possibly related to the protonation of Fe(VI) (HFeO4- <==> H+ + FeO4(2-); pK(a,HFeO4) = 7.23) and sulfonamides (SH <==> H+ + S-; pK(a,SH) = 5.0-7.4). The activation parameters of the reactions vary with pH due to temperature dependence on the protonation of Fe(VI) and sulfonamides. These results were used to obtain enthalpy of dissociation of sulfonamides. Stoichiometry and products of sulfamethoxazole (SMX) reactions with Fe(VI) were studied in detail using various analytical techniques to evaluate the effect of the oxidation process on the fate of sulfonamides in water. At a stoichiometric ratio of 4:1 (Fe(VI): SMX), complete removal of SMX was achieved. Analyses of oxidation products of the reaction as well as kinetic measurements of substructural models of SMX suggest that the attack of Fe(VI) occurs at the isoxazole moiety as well as at the aniline moiety with minimal preference. The results of the studies reported suggest that Fe(VI) has the potential to serve as a chemical oxidant for removing sulfonamides and converting them to relatively less toxic byproducts in water.

Authors+Show Affiliations

Department of Chemistry, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA. vsharma@fit.eduNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17180970

Citation

Sharma, Virender K., et al. "Oxidation of Sulfonamide Antimicrobials By ferrate(VI) [Fe(VI)O4(2-)]." Environmental Science & Technology, vol. 40, no. 23, 2006, pp. 7222-7.
Sharma VK, Mishra SK, Nesnas N. Oxidation of sulfonamide antimicrobials by ferrate(VI) [Fe(VI)O4(2-)]. Environ Sci Technol. 2006;40(23):7222-7.
Sharma, V. K., Mishra, S. K., & Nesnas, N. (2006). Oxidation of sulfonamide antimicrobials by ferrate(VI) [Fe(VI)O4(2-)]. Environmental Science & Technology, 40(23), 7222-7.
Sharma VK, Mishra SK, Nesnas N. Oxidation of Sulfonamide Antimicrobials By ferrate(VI) [Fe(VI)O4(2-)]. Environ Sci Technol. 2006 Dec 1;40(23):7222-7. PubMed PMID: 17180970.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oxidation of sulfonamide antimicrobials by ferrate(VI) [Fe(VI)O4(2-)]. AU - Sharma,Virender K, AU - Mishra,Santosh K, AU - Nesnas,Nasri, PY - 2006/12/22/pubmed PY - 2007/2/14/medline PY - 2006/12/22/entrez SP - 7222 EP - 7 JF - Environmental science & technology JO - Environ Sci Technol VL - 40 IS - 23 N2 - Sulfonamide antimicrobials are used in both human therapy and animal husbandry. Sulfonamides are not readily biodegradable and have been detected in surface water and in secondary wastewater effluents. The chemical oxidation of sulfonamides by an environmentally friendly oxidant, ferrate(VI) (Fe(VI)O4(2-), Fe(VI)), was conducted. The sulfonamides used in the oxidation studies were sulfisoxazole, sulfamethazine, sulfamethizole, sulfadimethoxine, and sulfamethoxazole. Kinetics of the reactions were determined as a function of pH (7.0-9.7) and temperature (15-45 degrees C) by a stopped-flow technique. The rate law for the oxidation of sulfonamides by Fe(VI) is first-order with respect to each reactant. The observed second-order rate constants decreased nonlinearly with an increase in pH and are possibly related to the protonation of Fe(VI) (HFeO4- <==> H+ + FeO4(2-); pK(a,HFeO4) = 7.23) and sulfonamides (SH <==> H+ + S-; pK(a,SH) = 5.0-7.4). The activation parameters of the reactions vary with pH due to temperature dependence on the protonation of Fe(VI) and sulfonamides. These results were used to obtain enthalpy of dissociation of sulfonamides. Stoichiometry and products of sulfamethoxazole (SMX) reactions with Fe(VI) were studied in detail using various analytical techniques to evaluate the effect of the oxidation process on the fate of sulfonamides in water. At a stoichiometric ratio of 4:1 (Fe(VI): SMX), complete removal of SMX was achieved. Analyses of oxidation products of the reaction as well as kinetic measurements of substructural models of SMX suggest that the attack of Fe(VI) occurs at the isoxazole moiety as well as at the aniline moiety with minimal preference. The results of the studies reported suggest that Fe(VI) has the potential to serve as a chemical oxidant for removing sulfonamides and converting them to relatively less toxic byproducts in water. SN - 0013-936X UR - https://www.unboundmedicine.com/medline/citation/17180970/Oxidation_of_sulfonamide_antimicrobials_by_ferrate_VI__[Fe_VI_O4_2__]_ L2 - https://doi.org/10.1021/es060351z DB - PRIME DP - Unbound Medicine ER -