Key Laboratory of Coastal Environmental Process and Ecology Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
University of Chinese Academy of Sciences, Beijing, China.
Environ Sci Pollut Res Int. 2017 Sep;24(27):21929-21937. doi: 10.1007/s11356-017-9693-y. Epub 2017 Aug 5.
Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing factors such as pH and salinity usually varied in a wide range. In this study, batch-type and stirred flow chamber (SFC) experiments were carried out to simulate the sorption-desorption behavior of trimethoprim (TMP) in seawater-sediment system. Equilibrium and kinetic modeling were carried out to determine the rate and extent of TMP sorption on two marine sediments with different properties. Sediment BHB (K , 6.40 L kg) has a greater sorption capacity compared with sediment LZB (K , 3.40 L kg), which is related to the higher content of organic carbon and clay of sediment BHB. Adsorption of TMP varied in the pH range of 6.9 to 8.1 with maximum adsorption at pH 7.4. Increasing salinity and presence of phosphate and nitrate led to decreased TMP sorption. Attenuated total reflection Fourier transform infrared (ATR-FTIR) analysis demonstrated the formation of hydrogen bond between TMP and marine sediments. Adsorption of TMP on marine sediments was a non-equilibrium process that can be described with second-order kinetic model. Our analysis suggested that chemical non-equilibrium was the rate controlling process and intraparticle diffusion was also involved in TMP adsorption. A moderate desorption percentage (16.4-22.8% for LZB and 32.5-42.0%for BHB) was observed. Overall, the results showed that environmental factors and time-dependent processes need to be considered in modeling the fate and transport of TMP in coastal/estuarine waters.
抗生素在天然水生态环境中的吸附-解吸行为较为复杂，尤其在沿海或河口地区，pH 值和盐度等影响因素的变化范围通常较宽。本研究采用批式和搅拌流室（SFC）实验模拟了磺胺甲噁唑（TMP）在海水-沉积物体系中的吸附-解吸行为。通过平衡和动力学模型来确定 TMP 在两种具有不同性质的海洋沉积物上的吸附速率和程度。与沉积物 LZB（K ，3.40 L kg ）相比，沉积物 BHB（K ，6.40 L kg ）具有更大的吸附容量，这与沉积物 BHB 中较高的有机碳和粘土含量有关。TMP 的吸附在 pH 值为 6.9 到 8.1 之间变化，在 pH 值为 7.4 时吸附量最大。盐度增加以及磷酸盐和硝酸盐的存在会导致 TMP 吸附减少。衰减全反射傅里叶变换红外（ATR-FTIR）分析表明 TMP 与海洋沉积物之间形成了氢键。TMP 在海洋沉积物上的吸附是非平衡过程，可以用二级动力学模型来描述。我们的分析表明，化学非平衡是控制过程，颗粒内扩散也参与了 TMP 的吸附。观察到中等的解吸百分比（LZB 为 16.4-22.8%，BHB 为 32.5-42.0%）。总的来说，研究结果表明，在模拟沿海/河口地区 TMP 的归趋和运移时，需要考虑环境因素和时间相关过程。
