Abstract:

Nearly 25% of the total area in Beijing is fluvo-aquic soils, whose adsorption characteristics of tetracycline antibiotics have not been investigated. This research, with the help of OECD Guideline 106, investigated the absorption characteristics of oxytetracycline in the fluvo-aquic soils in Beijing. Our research found that the adsorption kinetics of oxytetracycline in the fluvo-aquic soils is correspond to Elovich equation. The initial concentration of oxytetracycline will affect the adsorption rate. Absorption rate reaches the maximum when the concentration is 2 mg/L and the minimum when 10 mg/L. For absorption percentage, as initial concentration increases, the adsorption percentage first increases and then decreases. The relationship between temperature and average absorption rate is negatively correlated. In our experimental context, the adsorption isotherm is consistent with both linear adsorption isotherm equation and Freundlich isotherm equation. The adsorption is a spontaneous endothermic reaction. Fluvo-aquic soils adsorption capacity of oxytetracycline has a positive relation with the content of silt and clay. Adsorption of oxytetracycline on fluvo-aquic soils was affected by initial concentration, temperature, and soil properties. It is helpful to control pollution of oxytetracycline and protect soils if the mechanisms are understood deeply.

Key words: oxytetracycline, fluvo-aquic soils, adsorption, Beijing