3种四环素类抗生素在褐土上的吸附和解吸

以OECD Guideline 106为基础,采用批量平衡方法研究3种四环素类抗生素在褐土上的吸附和解吸作用.结果表明,3种四环素类抗生素的吸附和解吸不同程度地偏离线性模型,其中Freundlich模型可以对吸附和解吸数据进行良好的非线性拟合,平均拟合相关系数为0.991;其中金霉素的吸附等温线呈“S型”,土霉素的吸附等温线呈“L型”,而四环素的吸附等温线呈线性.在2种褐土中,金霉素吸附容量(lgKf) (4.307和4.003)高于四环素,而四环素lgKf (3.252和3.198)高于土霉素lgKf (2.932和2.724).对于同一种抗生素,在2种褐土中的吸附容量和吸附强度并无显著差异性.此类抗生素在褐土中的吸附均以物理性吸附为主.土霉素在褐土中的滞后系数显著高于四环素和金霉素(P<0.01),而四环素和金霉素的解吸滞后系数之间无显著差异.

Adsorption and desorption of three tetracycline antibiotics in cinnamon soils of China

On the basis of the OECD Guideline 106, batch adsorption methods were employed to reveal the adsorption and desorption process of three tetracycline antibiotics in cinnamon soils. The Freundlich model was the best isotherm to describe all experimental datas of adsorption and desorption, and the average fitting correlation coefficient was 0.991. Among three antibiotics, chlortetracycline adsorption isotherms resembled S-type curves, oxytetracycline adsorption isotherms resembled the L-type curves, and tetracycline adsorption isotherms resembled the linear curves according to adsorption strength (1/n). For two soils, the adsorption capacity (lgKf) was in the order chlortetracycline (4.003 and 4.307) > tetracycline (3.198 and 3.252) > oxytetracycline (2.724 and 2.932). The dominant mechanism of three tetracycline antibiotics adsorption was physical adsorption in cinnamon soils. HI of oxytetracycline was significantly higher than that of tetracycline and chlortetracycline (P0.05) between tetracycline and chlortetracycline for HI.