中文摘要：

以OECD Guideline 106为基础,采用批平衡方法研究不同Ca^2＋离子强度（0.01、0.03、0.05、0.08和0.10 mol/L的CaCl2溶液）和不同阳离子（0.01 mol/L的NaCl、KCl、NH4Cl、MgCl2、CaCl2、ZnCl2和AlCl3溶液）对诺氟沙星在4种土壤（潮土、黄棕壤、水稻土和红壤）中的吸附-解吸影响.结果表明,随着溶液中Ca^2＋离子浓度的增加,诺氟沙星在土壤中的吸附参数Kf值逐渐减小并趋于稳定,两者间存在显著负相关（p≤0.05）.同时,Ca^2＋离子浓度的增加对低浓度诺氟沙星溶液的吸附影响相对高浓度而言不明显.低pH下,诺氟沙星主要以阳离子形态存在,吸附以阳离子吸附或氢键为主;在兼性离子状态时,则主要以静电吸附和偶极力为主.这是造成4种土壤中诺氟沙星吸附差异的根本原因.在不同离子强度下,土壤溶液中二价Ca^2＋离子存在则对诺氟沙星的活性吸附位点造成竞争性吸附,从而降低诺氟沙星的土壤吸附量.同时,不同阳离子导致诺氟沙星的土壤吸附存在差异.其影响趋势主要为价态的影响,即价态越高,竞争吸附能力越强：M＋（Na^＋、K^＋、NH^4＋）＜M^2＋（Ca^2＋、Mg^2＋、Zn^2＋）＜M^3＋（Al^＋）.

英文摘要：

On the basis of OECD Guideline 106, batch sorption methods were employed to reveal the effect of Ca^＋2 ion strength and different cations （0.01 mol/L solution of NaCl, KCl, NH4Cl, MgCl2, CaCl2, ZnCl2 and AlCl3 ） on norfloxacin （NOR） sorptlon-desorption process in four tested soils （Ustic Cambosols, Udic Argosols, Gleyic-Stagnic Anthrosols and Ali-Perudic Ferrosols）. Results indicate that sorption coefficient K1 values of NOR gradually decrease to a steady state with the increased concentration of calcium ion in solution. There exists a significantly negative correlation between Ca^2＋ ion strength and Kf value （p ≤0.05）. Compared with higher NOR concentrations, the effect of calcium ion concentration is negligible to the sorption at lower NOR concentrations. At the low pH, cationic form of NOR is predominant in equilibrium solutions, so cation sorption and hydrogen bonding could be the main sorption mechanism. Whilst at the zwitterlonic form of NOR （pH 6.3 - 8.4）, electrostatic adsorption or dipole moment may control the sorption process. This causes the different sorption behavior of NOR in the four soils. Thus, the calcium ion in solutions is competitively adsorbed to the active sorption sites so as to decrease the NOR sorption amount. Moreover, the different cations result in difference of NOR sorption. Cations of higher valencies are adsorbed more strongly to surface active sorotion sites, with the following order：M＋（Na^＋、K^＋、NH^4＋）〈M^2＋（Ca^2＋、Mg^2＋、Zn^2＋）〈M^3＋（Al^＋） .