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Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole.
Chemosphere. 2006 Jan; 62(1):128-34.C

Abstract

Sulfamethoxazole (SMX), a worldwide-applied antibacterial drug, was recently found in surface waters and in secondary wastewater effluents, which may result in ecotoxical effects in the environment. Herein, removal of SMX by environmentally-friendly oxidant, potassium ferrate(VI) (K(2)FeO(4)), is sought by studying the kinetics of the reaction between Fe(VI) and SMX as a function of pH (6.93-9.50) and temperature (15-45 degrees C). The rate law for the oxidation of SMX by Fe(VI) is first-order with respect to each reactant. The observed second-order rate constant decreased non-linearly from 1.33+/-0.08 x 10(3) M(-1)s(-1) to 1.33+/-0.10 x 10(0) M(-1)s(-1) with an increase of pH from 7.00 to 9.50. This is related to protonation of Fe(VI) (HFeO(4)(-) <==> H(+) + FeO(4)(2-); pK(a,HFeO(4)) = 7.23) and sulfamethoxazole (SH <==> H(+) + S(-); pK(a,SH)=5.7). The estimated rate constants were k(11)(HFeO(4)(-) + SH) = 3.0 x 10(4) M(-1)s(-1), k(12)(HFeO(4)(-) + S(-)) = 1.7 x 10(2) M(-1)s(-1), and k(13) (FeO(4)(2-) + SH) = 1.2 x 10(0) M(-1)s(-1). The energy of activation at pH 7.0 was found to be 1.86+/-0.04 kJ mol(-1). If excess potassium ferrate(VI) concentration (10 microM) is used than the SMX in water, the half-life of the reaction using a rate constant obtained in our study would be approximately 2 min at pH 7. The reaction rates are pH dependent; thus, so are the half-lives of the reactions. The results suggest that K(2)FeO(4) has the potential to serve as an oxidative treatment chemical for removing SMX in water.

Authors+Show Affiliations

Sharma VK
Department of Chemistry, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901, USA. vsharma@fit.edu
Mishra SK
No affiliation info available
Ray AK
No affiliation info available

MeSH

Anti-Bacterial AgentsIron CompoundsKineticsMolecular StructureOxidation-ReductionPotassium CompoundsSulfamethoxazoleWater Pollutants, ChemicalWater Supply

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15950258

Citation

Sharma, Virender K., et al. "Kinetic Assessment of the Potassium ferrate(VI) Oxidation of Antibacterial Drug Sulfamethoxazole." Chemosphere, vol. 62, no. 1, 2006, pp. 128-34.
Sharma VK, Mishra SK, Ray AK. Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole. Chemosphere. 2006;62(1):128-34.
Sharma, V. K., Mishra, S. K., & Ray, A. K. (2006). Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole. Chemosphere, 62(1), 128-34.
Sharma VK, Mishra SK, Ray AK. Kinetic Assessment of the Potassium ferrate(VI) Oxidation of Antibacterial Drug Sulfamethoxazole. Chemosphere. 2006;62(1):128-34. PubMed PMID: 15950258.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole. AU - Sharma,Virender K, AU - Mishra,Santosh K, AU - Ray,Ajay K, Y1 - 2005/06/13/ PY - 2004/12/13/received PY - 2005/03/18/revised PY - 2005/03/28/accepted PY - 2005/6/14/pubmed PY - 2006/8/15/medline PY - 2005/6/14/entrez SP - 128 EP - 34 JF - Chemosphere JO - Chemosphere VL - 62 IS - 1 N2 - Sulfamethoxazole (SMX), a worldwide-applied antibacterial drug, was recently found in surface waters and in secondary wastewater effluents, which may result in ecotoxical effects in the environment. Herein, removal of SMX by environmentally-friendly oxidant, potassium ferrate(VI) (K(2)FeO(4)), is sought by studying the kinetics of the reaction between Fe(VI) and SMX as a function of pH (6.93-9.50) and temperature (15-45 degrees C). The rate law for the oxidation of SMX by Fe(VI) is first-order with respect to each reactant. The observed second-order rate constant decreased non-linearly from 1.33+/-0.08 x 10(3) M(-1)s(-1) to 1.33+/-0.10 x 10(0) M(-1)s(-1) with an increase of pH from 7.00 to 9.50. This is related to protonation of Fe(VI) (HFeO(4)(-) <==> H(+) + FeO(4)(2-); pK(a,HFeO(4)) = 7.23) and sulfamethoxazole (SH <==> H(+) + S(-); pK(a,SH)=5.7). The estimated rate constants were k(11)(HFeO(4)(-) + SH) = 3.0 x 10(4) M(-1)s(-1), k(12)(HFeO(4)(-) + S(-)) = 1.7 x 10(2) M(-1)s(-1), and k(13) (FeO(4)(2-) + SH) = 1.2 x 10(0) M(-1)s(-1). The energy of activation at pH 7.0 was found to be 1.86+/-0.04 kJ mol(-1). If excess potassium ferrate(VI) concentration (10 microM) is used than the SMX in water, the half-life of the reaction using a rate constant obtained in our study would be approximately 2 min at pH 7. The reaction rates are pH dependent; thus, so are the half-lives of the reactions. The results suggest that K(2)FeO(4) has the potential to serve as an oxidative treatment chemical for removing SMX in water. SN - 0045-6535 UR - https://www.unboundmedicine.com/medline/citation/15950258/Kinetic_assessment_of_the_potassium_ferrate_VI__oxidation_of_antibacterial_drug_sulfamethoxazole_ DB - PRIME DP - Unbound Medicine ER -