Competitive adsorption of antibiotic tetracycline and ciprofloxacin on montmorillonite

As antibiotics continue to be released into soils, it poses a potential threat to human and animal health. The migration-transformation of contaminants in soils is strongly affected by adsorption on clay. Tetracycline (TC) and ciprofloxacin (CIP) which are extensively used have been attracted attention recently. Based on adsorption kinetics, isotherm, FT-IR, XRD and molecular simulation, the intercalation and environmental behavior of TC or CIP by montmorillonite (Mt) as single or mixed substance were studied and the adsorption mechanism was also proved. In the mixed system, the relationship between TC and CIP was a competition, but no preferential adsorption. The interaction between antibiotics in interlayer and the adsorption energies were simulated and calculated by molecular simulation to reveal the experimental results.