摘要
以蒙脱石为吸附剂进行水中2种喹诺酮类抗生素(环丙沙星和诺氟沙星)的静态吸附试验,考察初始浓度、pH值和阳离子强度对吸附性能的影响.结果表明,蒙脱石对环丙沙星和诺氟沙星的吸附过程均符合二级反应动力学方程,吸附速率常数分别为0.063和0.024 kg.mg-1.h-1.环丙沙星和诺氟沙星的吸附等温线均能较好地符合Freundlich方程,且lgKf值较大,具有较强的吸附能力.当溶液pH值小于环丙沙星和诺氟沙星的pKa2值时,具有较高吸附量;大于pKa2值时,吸附量急剧下降.环丙沙星和诺氟沙星阳离子以及兼性离子均可被蒙脱石吸附,在高pH值条件下,阴离子与蒙脱石表面络合可能是蒙脱石吸附去除环丙沙星和诺氟沙星的主要作用机制.Ca2+对吸附有重要影响,其浓度越高,环丙沙星和诺氟沙星的吸附量越低.
A static adsorption experiment was carried out to investigate the influence of initial concentration,pH,and cationic strength on adsorption of two kinds of quinolone antibiotics（ciprofloxacin and norfloxacin） on montmorillonite.The results showed that the adsorption process of ciprofloxacin and norfloxacin were consistent with pseudo-second-order kinetics,and the adsorption rate constants were 0.063 and 0.024 kg·mg-1·h-1 respectively.Adsorption isotherms were well described by Freundlich equation,and the high lgKf showed strong adsorption ability.When the solution pH was less than the pKa2 of ciprofloxacin and norfloxacin,the adsorption capacity was higher.The adsorption capacity decreased sharply when the solution pH was above the pKa2.Both cationic and zwitterionic forms of ciprofloxacin and norfloxacin could be adsorbed significantly.At higher pH,the complexation of anion on the montmorillonite surface might become the main mechanism.The concentration of Ca2＋ had a great influence on adsorption.The higher the concentration,the lower the adsorption capacity of ciprofloxacin and norfloxacin.
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2011年第6期64-68,共5页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(30671208,40773062)
中央高校基本科研业务费专项资金资助项目(21610410,21609709)
广东省自然科学基金重点资助项目(07117909)
广东省科技计划资助项目(2005B20801002,2006B20601003,2010B020311006)
广东省高校高层次人才项目
广州市科技计划资助项目(10A82070466)
东莞市科技计划资助项目(2007108101110)
惠州市科技研究计划资助项目(2009B010001009)
关键词
抗生素
喹诺酮类
水污染
蒙脱石
吸附
去除
动力学
antibiotics
quinolones
water pollution
montmorillonite
adsorption
removal
kinetics
