环丙沙星在盐碱土中吸附特性的研究

发布时间：2018-08-10 17:13

【摘要】：采用OECD guideline 106批平衡吸附法研究环丙沙星在碱土中的等温吸附特性、吸附动力学、吸附热力学以及pH值和Ca~(2+)浓度对其吸附的影响。结果表明环丙沙星在盐碱土中的吸附较好地符合Freundlich方程(拟合系数R~2=0.981),不同初始浓度的环丙沙星在盐碱土中的吸附过程符合准二级动力学方程,吸附常数为1.17×10~(-3)~5.67×10~(-3)kg·min~(-1)·m L~(-1)。吸附过程可分为快速吸附和慢速平衡两个阶段,初始浓度分别为80、100、120 mg·L~(-1)的环丙沙星吸附平衡时间为24 h,平衡吸附比例分别为89.9%、92.2%、92.7%。吸附热力学参数ΔG0且ΔH=-3.58 5 k J·mol~(-1),表明环丙沙星在盐碱土上的吸附为自发的放热反应。随着溶液pH值的升高,盐碱土对环丙沙星的吸附能力不断减弱,当pH9后吸附能力快速减少。以不同浓度CaCl_2作为背景液,环丙沙星在盐碱土中的等温吸附曲线用Freundlich方程拟合效果较好,lgKf值随着CaCl_2背景溶液浓度的增加而减小,且环丙沙星初始浓度较小时其所受离子强度的影响相对较小。
[Abstract]:The adsorption characteristics, adsorption kinetics, adsorption thermodynamics, pH value and Ca~ (2+) concentration of ciprofloxacin in alkaline soil were studied by OECD guideline 106 batch equilibrium adsorption method. The adsorption process of ciprofloxacin in saline-alkali soil conforms to the quasi-second-order kinetic equation, and the adsorption constant is 1.17 (-3) ~ 5.67 (-3) kg (-1) (-1) (-1). The adsorption process can be divided into two stages: fast adsorption and slow equilibrium. The initial concentration of ciprofloxacin is 80,100,120 mg 65 The adsorption thermodynamic parameters G0 and H=-3.585 K J.mol~(-1) indicate that the adsorption of ciprofloxacin on saline-alkali soil is spontaneous exothermic reaction. With the increase of pH value of solution, the adsorption capacity of saline-alkali soil to ciprofloxacin decreases rapidly after pH 9. The isothermal adsorption curves of ciprofloxacin in saline-alkali soil were fitted well by Freundlich equation. The lgKf value decreased with the increase of CaCl_2 background solution concentration, and the influence of ionic strength on the isothermal adsorption curves of ciprofloxacin was relatively small when the initial concentration of ciprofloxacin was small.
【作者单位】： 吉林农业大学资源与环境学院;吉林省商品粮基地土壤资源可持续利用重点实验室;国家供水水质监测网长春监测站;
【基金】：吉林省科技厅重大科技攻关专项(20130204054SF0) 吉教科合字[2014]第467号
【分类号】：X53;S156.4
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