地学前缘 ›› 2019, Vol. 26 ›› Issue (4): 279-286.DOI: 10.13745/j.esf.sf.2019.5.31

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不同形态洛美沙星在高岭土上的吸附特性

卞馨怡,毕二平   

  1. 水资源与环境工程北京市重点实验室; 中国地质大学(北京) 水资源与环境学院, 北京 100083
  • 收稿日期:2019-02-20 修回日期:2019-03-28 出版日期:2019-07-25 发布日期:2019-07-25
  • 通讯作者: 毕二平(1969—),男,博士,教授,博士生导师,主要从事污染水文地质与环境有机化学研究。
  • 作者简介:卞馨怡(1994—),女,硕士,水文地质学专业,主要研究方向为地下水环境。
  • 基金资助:
    国家自然科学基金项目(41472231)

Sorption characteristics of different forms of lomefloxacin on kaolinite

BIAN Xinyi,BI Erping   

  • Received:2019-02-20 Revised:2019-03-28 Online:2019-07-25 Published:2019-07-25
  • Supported by:
     

摘要: 本研究采用批实验方法探究了不同形态洛美沙星(LOM)在高岭土上的吸附特性。LOM吸附动力学结果符合准二级反应动力学方程,吸附等温数据可用Langmuir方程很好地拟合。随着溶液pH值增大,洛美沙星吸附量先增大后减小,且pH值在洛美沙星pKa1与pKa2间吸附量达到最大。不同形态LOM在高岭土上的吸附量排序为LOM±>LOM+>LOM-。溶液离子强度和无机阳离子种类对LOM+在高岭土上的吸附影响十分微弱,但均明显抑制了LOM±的吸附,且离子强度越大,抑制作用越明显。不同无机阳离子抑制程度排序为Mg2+>Ca2+>K+>Na+。LOM+在高岭土上的吸附机理主要是内层络合和阳离子交换;LOM±在高岭土上的吸附机理主要是阳离子交换、氢键作用和静电引力作用;LOM-与高岭土表面存在较大静电斥力,导致吸附量很小,可能是外层表面络合引起少量的吸附。

 

Abstract: We carried out batch experiments to investigate the sorption characteristics of different forms of lomefloxacin (LOM) on kaolinite. Sorption kinetics were pseudo-second-order, and all equilibrium data could be well described by the Langmuir equation. As solution pH increased, the amount of LOM sorption increased first and then decreased. Maximum sorption was achieved at pH values between pKa1 and pKa2 of LOM. The sorption capacity of different forms of LOM on kaolinite ranked as LOM±>LOM+>LOM-. The ionic strength of LOM solution and inorganic cations had little effect on LOM+ sorption, but both factors significantly inhibited LOM± sorption. The sorption capacity of LOM± decreased with increasing ionic strength, and the inhibition potency of different inorganic cations was in the order of Mg2+>Ca2+>K+>Na+. The sorption mechanisms were mainly inner-sphere complexation and cation exchange for LOM+ or cation exchange, hydrogen bonding and electrostatic attraction for LOM± on kaolinite. LOM- sorption on kaolinite is very small due to strong repulsive electrostatic effect; the small sorption may resulted from outer-sphere surface complexation.

Key words: lomefloxacin, kaolinite, sorption, different forms

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