School of Energy and Environment, Thapar Institute of Engineering and Technology, Patiala 147004, India.
Radiation Technology Development Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Chemosphere. 2018 Oct;208:606-613. doi: 10.1016/j.chemosphere.2018.06.003. Epub 2018 Jun 1.
Gamma radiolytic degradation of an antibiotic, ofloxacin (OFX) was investigated under different experimental conditions. The parameters such as initial OFX concentration, solution pH, absorbed dose and the concentrations of inorganic (CO) and organic (t-BuOH) additives were optimized to achieve the efficient degradation of OFX. The degradation dose constant values of OFX were calculated as 2.364, 1.159, 0.776 and 0.618 kGy for the initial OFX concentrations of 0.05, 0.1, 0.15 and 0.2 mM with their corresponding (G (-OFX)) values of 0.481, 0.684, 1.755 and 1.971, respectively. Degradation rate of OFX was significantly increased with increase in the absorbed dose and decrease in the initial OFX concentration under acidic condition when compared to neutral or alkaline condition. Reaction of OFX in the presence of CO and t-BuOH showed that the degradation was primarily caused by the reaction of OFX with radiolytically generated reactive hydroxyl radicals. Mineralization extent of OFX was determined in terms of percentage reduction in total organic carbon (TOC) and results revealed that the addition of HO enhanced the mineralization of OFX from 29% to 36.1% with HO dose of 0.5 mM at an absorbed dose of 3.0 kGy. Based on the LC-QTOF-MS analysis, gamma radiolytic degradation intermediates/products of OFX were identified and the possible degradation pathways of OFX were proposed. Cytotoxicity study of the irradiated OFX solutions showed that gamma radiation has potential to detoxify OFX.
在不同的实验条件下，研究了抗生素氧氟沙星（OFX）的伽马辐射降解。优化了初始 OFX 浓度、溶液 pH 值、吸收剂量以及无机（CO）和有机（t-BuOH）添加剂浓度等参数，以实现 OFX 的有效降解。计算出初始 OFX 浓度为 0.05、0.1、0.15 和 0.2 mM 时，OFX 的降解剂量常数值分别为 2.364、1.159、0.776 和 0.618 kGy，相应的（G(-OFX)）值分别为 0.481、0.684、1.755 和 1.971。与中性或碱性条件相比，在酸性条件下，随着吸收剂量的增加和初始 OFX 浓度的降低，OFX 的降解速率显著提高。在 CO 和 t-BuOH 的存在下，OFX 的反应表明降解主要是由 OFX 与辐射生成的活性羟基自由基反应引起的。通过总有机碳（TOC）的减少百分比来确定 OFX 的矿化程度，结果表明，在 3.0 kGy 的吸收剂量下，添加 0.5 mM 的 HO 可将 OFX 的矿化程度从 29%提高到 36.1%。基于 LC-QTOF-MS 分析，鉴定了 OFX 的伽马辐射降解中间产物/产物，并提出了 OFX 的可能降解途径。辐照 OFX 溶液的细胞毒性研究表明，伽马辐射有潜力使 OFX 解毒。
