环丙沙星在潮土中的吸附特性

为了探明环丙沙星在潮土中的吸附特性,采用静态吸附试验,研究了环丙沙星在潮土中的吸附动力学、等温吸附特性以及pH值对其吸附过程的影响.结果表明,环丙沙星在潮土中的吸附过程可分为快速吸附和慢速平衡2个阶段.整个吸附过程符合二级反应动力学方程,吸附常数为1.138×10-3～2.849×10-2kg.(min.mg)-1.环丙沙星的吸附等温线能够较好地符合Freundlich方程和Langmuir方程,其中Freundlich方程的拟合效果更佳,吸附容量(lgKf)为2.725.研究发现,在pH值为4～9条件下,环丙沙星的吸附参数对数值lgKd呈随pH的增加先增加后降低的趋势,当pH值为5时,潮土对环丙沙星的吸附效果最好,lgKd为3.11,强酸性和碱性条件均不利于潮土对环丙沙星的吸附.由此推断阳离子吸附可能是潮土对环丙沙星吸附的重要机制之一.

Adsorption Characteristics of Ciprofloxacin in Ustic Cambosols

In order to understand the adsorption characteristics of ciprofloxacin in ustic cambosols, static adsorption experiments were used to investigate dynamic and isothermal adsorption characteristics of ciprofloxacin in ustic cambosols, influence of pH on the adsorption process. Results showed that the absorption process of ciprofloxacin can be divided into two stages: fast adsorption and slow balance. The adsorption processes followed the pseudo-second-order kinetics, with adsorption rate of 1.138×10^-3-2.849×10^-2 kg ·(min ·mg)^-1. Adsorption isotherms of ciprofloxacin in ustic cambosols were well described by the Freundlich and Langmuir equation, Freundlich equation is more applicable than Langmuir equation, with the adsorption capacity(lgK_f) of 2.725. Moreover, at the tested pH interval of 4-9, lgK_dvalues of ciprofloxacin increased and then decreased with the increase of pH in ustic cambosols; the maximum adsorption of ciprofloxacin in ustic cambosols can be obtained when the pH value was 5 with lgK_d value was 3.11; strong acid or alkali conditions were unfavorable to ciprofloxacin adsorption. It could be deduced that cationic adsorptions was one of the significant sorption mechanisms for ciprofloxacin in ustic cambosols.