2种四环素类抗生素在凹凸棒石黏土中的吸附研究

Sorption Study of Two Tetracycline Antibiotics on Attapulgite

通过静态吸附实验,探究凹凸棒石黏土对四环素和土霉素的吸附动力学;采用准一级动力学、准二级动力学和颗粒内扩散模型拟合实验数据,分析吸附过程。测定凹凸棒石黏土对四环素和土霉素的动态吸附曲线和吸附容量,研究凹凸棒石黏土对水溶液中四环素和土霉素的动态吸附性能。探讨初始质量浓度对穿透曲线的影响,采用Thomas模型对动态试验数据拟合,获得相关参数。结果表明,凹凸棒石黏土能够有效去除水中的四环素和土霉素,且四环素的吸附容量高于土霉素,在初始浓度为400mg/L时,对四环素的饱和吸附量达74.5mg/g,对土霉素的饱和吸附量达69.2mg/g。穿透曲线呈S型,且随着初始浓度的增大,穿透点向左移,穿透时间缩短,平衡吸附量增加。

The adsorbing kinetics of attapulgite to tetracycline antibiotics is investigated by implementation of state adsorption experiments. The adsorption kinetics is tested for intraparticle diffusion,pseudo-first-order and pseudo-secondorder reactions and rate constants of kinetic models are calculated. The dynamic adsorption curve and adsorption capacity of attapulgite for tetracycline and oxytetracycline are determined for studying the adsorption ability. The effect of the initial concentration on breakthrough curve is studied. Moreover,Thomas model is applied to simulate column adsorption data and to obtain the characteristic parameters. The results show that attapulgite as an adsorbent to remove tetracycline and oxytetracycline from solution is efficient,and the adsorption capacity in the order tetracycline oxytetracycline. At the initial concentration of tetracycline antibiotics 400mg/L,the equilibrium absorption capacity of tetracycline and oxyteracycline is 74.5mg/g and 69.2mg/g respectively. S-shaped breakthrough curves are obtained at different initial concentrations. With increase of the initial concentration of tetracycline antibiotics,the breakthrough point moves to left,suggesting the decrease of breakthrough time,and equilibrium absorption capacity increases.