Department of Chemistry and Biochemistry, California State University-Long Beach, CA 90840, USA.
Chemosphere. 2010 Sep;81(3):359-65. doi: 10.1016/j.chemosphere.2010.07.015. Epub 2010 Aug 10.
The quantitative removal of contaminant antibiotic activity from waters intended for reuse is one of the biggest problems facing water utilities today. As conventional water treatments are not sufficient, advanced Oxidation and Reduction Processes (AO/RPs) are being considered for additional remediation. In support of the potential use of sulfate radical based AO/RPs, we have determined the reaction rate constants for the sulfate radical with a large library of β-lactam antibiotics. The SO(4)(-)() reactivity with the five-member ring species was found to have an extrapolated zero ionic strength average rate constant of (1.6±0.9) x 10(9)M(-1)s(-1), slightly slower than for the six-member antibiotics at (2.1±0.6) x 10(9)M(-1)s(-1). Transient spectral studies indicated that the majority of these radicals reacted at the five- or six-member rings adjacent to the β-lactam core, predominately at the sulfur atom and the double bond, respectively. As these oxidations occur next to the β-lactam moiety, rather than at the peripheral aromatic rings observed for hydroxyl radical reaction, sulfate radical remediation through the use of added persulfate might result in more efficient antibiotic activity removal than when using a traditional AO/RP treatment.
从用于再利用的水中定量去除污染物抗生素活性是当今水处理公司面临的最大问题之一。由于常规水处理方法不够有效，因此正在考虑采用高级氧化还原工艺 (AO/RP) 进行额外的修复。为了支持基于硫酸根自由基的 AO/RP 的潜在用途，我们已经确定了硫酸根自由基与大量β-内酰胺抗生素的反应速率常数。发现 SO(4)(-)()与五元环物质的反应具有外推至零离子强度的平均速率常数为 (1.6±0.9) x 10(9)M(-1)s(-1)，略慢于六元环抗生素的 (2.1±0.6) x 10(9)M(-1)s(-1)。瞬态光谱研究表明，这些自由基中的大多数在与β-内酰胺核相邻的五元或六元环上反应，分别主要在硫原子和双键上反应。由于这些氧化发生在β-内酰胺部分旁边，而不是羟基自由基反应中观察到的外围芳环上，因此通过添加过硫酸盐进行硫酸根修复可能会比传统的 AO/RP 处理更有效地去除抗生素活性。
