四环素在土壤中的吸附与解吸以及镉在其中的影响

采用批平衡实验方法,研究了四环素（TC）在褐土和红壤中的吸附和解吸,以及Cd2＋对四环素在两种土壤上吸附和解吸的影响。结果表明,四环素在褐土和红壤中的吸附可以用Freundlich等温吸附方程拟合,所得lgKf分别为3.039和3.169,这表明四环素在红壤中的吸附能力较强。此外,四环素在两种土壤上的解吸过程都存在滞后现象,所得lgKf,des分别为3.292和3.877,这将可能威胁到土壤环境和人体健康。常见重金属Cd2＋的存在会促进四环素在两种土壤上的吸附,在红壤中表现显著（P〈0.05）;同时红壤中四环素的lgKf,des有所增加,而在褐土中的变化不大。

Adsorption and Desorption of Tetracycline and Effect of Cadmium on These in Two Typical Soils of China

Tetracycline（TC ） has been extensively used in human infection medicines and veterinary medicines, especially in China. Heavy metals and antibiotics often coexist in soil due to land application of anmial wastes and other sources of inputs. On the basis of the OECD Guideline 106, batch sorption methods were employed to reveal the effect of Cd2＋ on TC sorption and desorption process in two tested soils （cinnamon soil and red soil）. Results showed that the Freundlich model was the best isotherm to describe the experimental datas of adsorption and desorption. The lgKf on cinnamon soil and red soil were 3.039 and 3.169, respectively, which showed that red soil had more stronger sorption capacity for TC than cinnamon soil. Heavy metals Cd2＋ could promote TC sorption on two tested soils, especially in red soil（P〈0.05 ）. The appararent sorption-desorption hysteresis were found in two soils, and the lgKr.des on two soils were 3.292 and 3.877 respectively. The lgKf.des in red soil increased with the addition of Cd2＋, but little change in cinnamon soil. It is important to consider the interaction of Cd2. and TC when modeling the fate of Cd2＋ and TC in soil.