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|Title:||Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole|
|Citation:||Sharma, V.K., Mishra, S.K., Ray, A.K. (2006-01). Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole. Chemosphere 62 (1) : 128-134. ScholarBank@NUS Repository. https://doi.org/10.1016/j.chemosphere.2005.03.095|
|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) (K2FeO 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°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 × 103 M-1 s-1 to 1.33 ± 0.10 × 100 M-1 s-1 with an increase of pH from 7.00 to 9.50. This is related to protonation of Fe(VI) (HFeO4-⇔H++FeO42-; pKa,HFeO4 = 7.23) and sulfamethoxazole (SH ⇔ H+ + S-; pKa,SH = 5.7). The estimated rate constants were k11 (HFeO4-+SH)=3.0×104 M-1 s-1, k12 (HFeO4-+S-)=1.7×102 M-1 s -1, and k13 (FeO42-+SH)=1.2×100 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 μM) 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 K2FeO4 has the potential to serve as an oxidative treatment chemical for removing SMX in water.|
|Appears in Collections:||Staff Publications|
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