Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole.
Kinetic assessment of the potassium ferrate(VI) oxidation of antibacterial drug sulfamethoxazole.
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DOI：
10.1016/j.chemosphere.2005.03.095
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发表时间：
2006
期刊：
影响因子：
8.8
通讯作者：
V. Sharma;S. Mishra;A. Ray
中科院分区：
文献类型：
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作者：
V. Sharma;S. Mishra;A. Ray
磺胺甲恶唑（SMX）是一种广泛应用的抗菌药物，近年来发现存在于地表沃茨和二级污水排放中，可能对环境产生生态毒性效应。在本文中，通过研究Fe（VI）和SMX之间的反应动力学作为pH（6.93-9.50）和温度（15-45°C）的函数，寻求通过环境友好的氧化剂高铁酸钾（VI）（K2 FeO 4）去除SMX。Fe（VI）对SMX的氧化速率对各反应物均为一级反应。随着pH值从7.00增加到9.50，二级速率常数从1.33±0.08× 103 M − 1 s − 1非线性地降低到1.33±0.10× 100 M − 1 s − 1。这与Fe（VI）（HFeO 4-惠H++ FeO 42-; pKa，HFeO 4 =7.23）和磺胺甲恶唑（SH惠H++S−; pKa，SH=5.7）的质子化有关。估计的速率常数为k11（HFeO 4-+SH）=3.0× 104 M − 1 s −1，k12（HFeO 4-+S-）=1.7× 102 M − 1 s −1，k13（FeO 42-+SH）=1.2× 100 M − 1 s −1。pH 7.0时的活化能为1.86±0.04kJmol−1。如果使用的高铁酸钾（VI）浓度（10μM）超过SMX在水中的浓度，则使用我们研究中获得的速率常数的反应半衰期在pH 7下约为2 min。反应速率取决于pH值;因此，反应的半衰期也是如此。结果表明，K2 FeO 4有可能作为一种氧化处理化学去除SMX在水中。
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) (K2FeO4), 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±0.08×103M−1s−1to 1.33±0.10×100M−1s−1with 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)=3.0×104M−1s−1, k12(HFeO4-+S-)=1.7×102M−1s−1, and k13(FeO42-+SH)=1.2×100M−1s−1. The energy of activation at pH 7.0 was found to be 1.86±0.04kJmol−1. If excess potassium ferrate(VI) concentration (10μM) is used than the SMX in water, the half-life of the reaction using a rate constant obtained in our study would be approximately 2min at pH 7. The reaction rates are pH dependent; thus, so are the half-lives of the reactions. The results suggest that K2FeO4has the potential to serve as an oxidative treatment chemical for removing SMX in water.