Study of the sorption/desorption behavior of chlortetracycline on sediments in the upper reaches of the Yellow River

Abstract The presence of antibiotic in aquatic environments has become a topic of great concern with respect to both environment and global public health. However, to date, only a few studies have been carried out on the sorption behavior of antibiotics in aquatic environments. In this study, batch equilibrium experiments were conducted to explore the sorption/desorption behavior of Chlortetracycline (CTC) on the sediments in the Lanzhou section of the Yellow River. The results showed multilayer chemisorption on heterogeneous surfaces dominated by hydrophobic distribution and an obvious hysteresis phenomenon was observed. In addition, the sorption was found to be influenced by factors such as a continuous increase in the temperature, reduction in the initial concentration of CTC, and the increasing particle size of the sediments. The pH was found to affect the dissociation degree of CTC, and the sorptive amount was found to decrease with the increase in the pH value. The presence of other ions which with high valence state and concentration presenting an obvious inhibitory effect in the sorption process. Additionally, the large sorptive amount of antibiotics in the sediments due to the high Cation exchange capacity (CEC), organic matter, and clay particles indicated the influence of the physicochemical properties of sediments on the sorption behavior of antibiotics. This study preliminarily grasps the trend of CTC sorption/desorption on sediments, which is helpful in understanding the fate of CTC and assessing its ecological risks in the upper reaches of the Yellow River.