Interactions of tetracycline with Cd (II), Cu (II) and Pb (II) and their cosorption behavior in soils

Tetracycline (TC), a common antibiotic, can behave as an efficient ligand with cations, but the effect of its interaction with heavy metal cations on the mobility of both species in soils has not been well evaluated. In this study, the complexation affinities of TC with Cd (II), Cu (II) and Pb (II) were examined using potentiometric titration and spectroscopic methods. The cosorption behavior of TC and metal ions onto three selected Chinese soils was evaluated using batch adsorption experiments. The presence of metal cations promoted TC adsorption through an ion bridging effect in the order Cu (II) > Pb (II) > Cd (II), which is in accordance with their complexation ability with TC. The addition of TC affects metal adsorption differently depending on the solution pH and metal type. Therefore, it is necessary to consider the complexation ability of TC and divalent metal cations when evaluating their mobility in soils. -- Highlights: •The complex affinity with TC has an order of Cu(II) > Pb(II) > Cd(II). •The complexation constants of TC with the three metals are obtained. •The cosorption behavior in soils greatly depends on the complexation affinity. -- The interaction between tetracycline and metal cations can influence the adsorption behavior of these species in soils, depending on their complexation ability