土壤粒度对土霉素在黑土和红壤上吸附的影响

为了探明土壤粒度对土霉素在土壤上吸附的影响,以性质差异显著的黑土和红壤为供试土壤,采用批量平衡法,研究了土霉素在不同粒度的2种土壤上的吸附行为。结果表明：（1）土霉素在不同粒度土壤上的吸附均分为快吸附和慢吸附2个过程,土壤类型和不同粒度的同种土壤对土霉素吸附速率存在差异,Elovich模型、双常数模型对动力学吸附过程拟合效果最好;（2）3种等温吸附方程模型都可以较好地拟合研磨度不同的2种土壤对土霉素的吸附,相关系数（R^2）在0.954～0.999之间,吸附参数kd、kf在2种土壤上均随着粒度的减小而增大。因此,在研究土霉素等四环素类抗生素在土壤上的吸附时选择合适的土壤粒度非常重要。

Influence of Particle Size on the Adsorption of Oxytetracycline on Black Soil and Red Soil

Oxytetracyline is widely used in the world as veterinary medicine to treat and prevent infectious bacterial diseases and to promote animal growth. Although the amount of oxytetracycline used in animal body is very low,it can be almost completely excreted from the body after a short time of residence and then easily enter into soil environment. The two contrasting soils including Black soil and Red soil were selected to investigate the influence of particle size of soil on the adsorption of oxytetracycline on to soils,using the method of batch equilibrium experiments. The results showed that adsorption processes of OTC on soils with different particle sizes consisted of quick adsorption and slow adsorption. Oxytetracycline adsorption consisted of fast and slow adsorption processes. Adsorption rate of OTC were related with soil types and particle sizes. Elovich kinetic model and Two-constant kinetic model could be used to well fit the kinetic processes of adsorption of oxytetracycline on to two soils. Freundlich model,Langmuir model,and linear model could be used to fit OTC isothermal adsorption on two soils at the different particle sizes. The correlation coefficient（R^2） were between 0.954-0.999. The values of kd,kf for adsorption of oxytetracycline on two soils both increased with the decreasing soil particle size. These results suggested that it was very important to select the appropriate particle size when the adsorption of antibiotics such as tetracyclines on to soils was investigated.