土壤有机质对土霉素在土壤中吸附-解吸的影响

采用批量平衡方法,研究了土霉素在原土及去除有机质土壤中的吸附和解吸.结果表明,土霉素在原土和去除有机质土壤中的吸附和解吸等温线均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,在不同土壤以及不同土壤处理中的拟合相关系数(r)均达到极显著水平.去除有机质能够降低土霉素在土壤中的吸附容量(lgKf),但增加了吸附强度(1/n).土霉素在土壤上的解吸过程存在明显的滞后现象,在所设土霉素浓度范围内,土霉素在褐土和红壤中的平均滞后系数(HIa)分别为0.039和0.015;去除有机质后的褐土和红壤对土霉素的解吸滞后现象显著增强(P<0.01),其HIa分别增加到0.068和0.028.

Effect of soil organic matter on adsorption and desorption of oxytetracycline in soils.

Batch equilibrium experiments were used to investigate the adsorption and desorption of oxytetracycline (OTC) in cinnamon soil and red soil with or without soil organic matter (SOM). Results showed that all adsorption and desorption isotherms were of deviation from the linear model. All experimental adsorption and desorption data could be best described by the Freundlich model, and all coefficients (r) were up to a very significant correlation. Removal of SOM could reduce OTC adsorption capacity (lgKf) and increase OTC adsorption strength (1/n) in soil. The apparent adsorption-desorption hysteresis was found with the average hysteresis index (HIa) 0.039 and 0.015 in cinnamon soil and red soil. The removal of SOM could significantly increase HIa (P <0.01) in cinnamon soil and red soil to 0.068 and 0.028, respectively.