左氧氟沙星在针铁矿-溶液体系存在形态对大肠杆菌的毒性效应

The toxic effect of Levofloxacin on Escherichia coli in Goethite solution system

通过批试验研究了针铁矿存在时,左氧氟沙星对大肠杆菌的毒性效应以及吸附态的左氧氟沙星对微生物生长的影响.结果表明,中性条件下存在培养基时,左氧氟沙星在针铁矿上4 h可达到吸附平衡,吸附等温线符合Freundlich吸附方程,傅里叶变换红外光谱分析得出左氧氟沙星的羧酸基团和酮基基团与针铁矿表面发生络合作用;0.016 g针铁矿的存在一定程度上能够促进大肠杆菌的生长(约50%),随着针铁矿含量的变化(0—0.1 g),在扣除其生长促进的影响后左氧氟沙星对大肠杆菌的毒性作用仍显著减弱,由90%降低至60%.

This study was to investigate the toxic effect of levofloxacin on Escherichia coli with goethite using batch equilibrium experiments. The effect of adsorbed levofloxacin on microbial growth was also analysed. The results showed that, in neutral solutions, containing culture medium, the adsorption of levofloxacin on goethite reached equilibrium in 4 h, which was fitted to Freundlich isotherm. Fourier transform infrared spectroscopy analysis indicated that levofloxacin formed a complex on the goethite surface through keto and carboxylate groups. A dosage of 0. 016 g goethite promoted the growth of Escherichia coli by 50%. The toxic effect on Escherichia coli was significantly decreased by the adsorbed levofloxacin when the dosage of goethite was between 0—0. 1 g. The inhibition rate of levofloxacin on the growth of Escherichia coli decreased from 90% to 60% after deducting the impact of the promotion on Escherichia coli growth by goethite.