中文摘要：

通过控制反应体系的pH值,探究了阳离子、兼性和阴离子形态的氧氟沙星（OFL,3种形态分别记为OFL＋,OFL±和OFL-）在凹凸棒土（ATP）上的吸附特征.实验结果表明,OFL＋主要通过与ATP表面的Ca2＋,Mg2＋进行阳离子交换吸附于ATP上,当其吸附量较高时,会存在少量的氢键;OFL±和OFL-可与ATP表面的铁氧化物、铝氧化物进行表面络合,也可与溶液中从ATP中溶解出的Ca2＋和Mg2＋形成络合物,再通过静电作用吸附于ATP上.在中性至微碱性（pH=7.107.70）条件下,由于Ca的电负性小于Mg,[Ca2＋-OFL]＋不能稳定地存在于溶液中,使得OFL±与Ca2＋进行阳离子交换而与Mg2＋形成络合物,再通过静电作用吸附于ATP上.当OFL主要以OFL-形态存在于溶液中时（p H=9.0010.00）,Ca2＋和Mg2＋均可与OFL-形成络合物,再通过静电作用吸附于ATP上.

英文摘要：

By controlling the p H of reaction system,the adsorption characteristics of different forms of ofloxacin（ i. e.,OFL±,OFL＋,and OFL-） to attapulgite（ ATP） were investigated. The experimental results showed that exchanging with Ca2＋and Mg2＋on the surface of ATP was the main sorption mechanism for OFL＋.When OFL＋adsorption quantity increased,there will be little amount of hydrogen bonding between OFL＋and ATP surface. OFL±and OFL-can form surface complexation with iron/aluminum oxide on the surface of ATP.Meanwhile,both OFL± and OFL-can form complexes with cations（ Ca2＋,Mg2＋） dissolved from ATP and then adsorbed on ATP by electrostatic attraction. Because of the lower electronegativity of Ca than Mg,[Ca2＋-OFL]＋cannot exist stably in neutral to weakly alkaline（ e. g.,pH = 7. 10—7. 70） solution,which results in the situation that OFL±exchange with Ca2＋but form complexes with Mg2＋then adsorbed to ATP by electrostatic attraction. When OFL-was the main form in solution（ pH = 9. 00—10. 00）,both Ca2＋and Mg2＋ can form complexes with OFL-and then adsorbed to ATP by electrostatic attraction.