四环素类抗生素在黑土和白浆土中吸附规律研究

Adsorption behaviour of tetracycline antibiotics in black soil and albic soil

文章采用批量平衡方法研究四环素和土霉素在黑土和白浆土中吸附规律。结果表明,土壤对四环素类抗生素吸附平衡时间为24 h;对比Elovich方程、双常数方程和抛物线方程,一级动力学模型对两种抗生素在土壤中吸附动力学行为拟合效果最好。从吸附热力学结果上看,黑土和白浆土对四环素吸附能力均高于土霉素;Freundlich模型对吸附数据非线性拟合良好,平均拟合相关系数为0.988,四环素和土霉素在土壤中吸附强度(1/n)差异性显著,但均小于1,四环素和土霉素吸附等温线为"L型"。四环素和土霉素在黑土和白浆土中|ΔG|均小于40k J·mol^(-1),四环素和土霉素在黑土和白浆土中吸附过程主要是物理吸附为主自发反应,四环素和土霉素在黑土和白浆土中移动性极低,对环境造成污染。

The paper studied the adsorption behavior of tetracycline and oxytetracycline in black soil and albic soils with a batch equilibrium method. The results showed that adsorption equilibrium could be achieved after 24 h of vibration, so that the time of 24 h could be used as an adsorption equilibrium time of adsorption of tetracycline antibiotics in soil. The first order kinetic model had better fitting effect on adsorption kinetics of the two antibiotics in soil, comparing to Elovich equation, dual constant equation and parabolic equation. From the view of the thermodynamics of adsorption, black soil and albic soils had larger adsorption capacity for tetracycline than that for oxytetracycline; Freundlich model had good nonlinear fitting on the adsorption data, with an average fitting correlation coefficient of 0.988. There were large difference in strength of absorption （l/n） in soils between tetracycline and oxytetracycline, while the value of 1In were all less than 1, indicting that the adsorption isotherms of tetracycline and oxytetracycline in black soil and albic soil belonged to ＂L＂ type. The values of IAGI were less than 40 kJ·mol^-1, which indicated that the adsorption of tetracycline and oxytetracycline in albic soil and black soil were mainly spontaneous physical processes. Also, we found that tetracycline and oxytetracycline had quite low mobility in albic soil and black soil, easy to cause environmental pollution.