为了更全面认识环丙沙星(CIP)在不同背景土壤中的迁移特性，在华北平原地下水灌溉农田区选择有机质组成特征和理化性质显著的两处土壤样品，从动力学和热力学两方面研究CIP在土壤中的吸附-解吸机制。结果显示，动力学实验数据更符合准二级动力学方程，等温模式呈非线性特征、Langmuir模型拟合效果最优。吸附动力学常数(K2，8 772。64vs2 846。37 g/(mg·h))、吸附平衡速率常数(K1，0。113 vs 0。094 L/mol)及最大吸附量(Qm，5 033 vs 3 167 mg/kg)参数均呈现出献县样品大于正定样品，指示献县土壤更快的吸附速率和更大的吸附容量。相应地，解吸实验得到的解吸率(5。98％vs 8。07％)、最大解吸量(6 592 vs 7 564 mg/kg)及由热力学计算所得吸附自由能△G(-25。08 vs-23。00kJ/mol)大小均一致反映出献县土壤相较正定土壤对CIP的吸附性能更强。综合实验研究结果和光谱特征、理化参数特征分析得出，献县土壤的高分子、高芳香性和多官能团的腐殖质成分以及更高黏粒含量是其吸附性能整体表现更强的重要因素，腐殖质分子的疏水作用和静电作用等物理吸附机制可能对献县土壤吸附CIP起到更加积极的作用。
Adsorption and Desorption Characteristics of Ciprofloxacin in Soil of Groundwater Irrigation Area
In order to better understand the migration characteristics of ciprofloxacin(CIP)in specific types of soils,two soil samples with significant organic matter composition and physical and chemical properties potentially influenced by different geological and environmental backgrounds were selected from the groundwater irrigated farmland area of the North China Plain,and the adsorption-desorption mechanism of CIP in soil was studied kinetically and thermodynamically.The findings show that the kinetic experimental data are more in line with the quasi-second-order kinetic equation and the isothermal models are nonlinear,of which the Langmuir model turns out the best fitting.The parameters of adsorption kinetics constant(K2,8 772.64 vs 2 846.37 g/(mg-h)),adsorption equilibrium rate constant(K1,0.113 vs 0.094 L/mol)and maximum adsorption capacity(Qm,5 033 vs 3 167 mg/kg)altogether exhibited higher values for Xianxian samples than those for the Zhengding,indicating faster adsorption rate and greater adsorption capacity of Xianxian soil.Correspondingly,the desorption rate(5.98％vs 8.07％),the maximum desorption amount(6 592 vs 7 564 mg/kg)and the adsorption free energy △G(-25.08 vs-23.00 kJ/mol)obtained from the desorption experiment consistently reflected that the soil in Xianxian County had better adsorption performance for CIP than the soil in Zhengding County.Based on the results of comprehensive experimental research and the analysis of spectral characteristics and physicochemical parameters,it is concluded that the high molecular weight,high aromaticity and multi-functional humus components of Xianxian soil and higher clay content are important factors for its overall better adsorption effect.The physical adsorption mechanism such as hydrophobic effect and electrostatic effect of humus molecules may play more active role in the adsorption of CIP antibiotics in Xianxian soil.
farmland soilgroundwater irrigationciprofloxacinadsorb-desorptionNorth China Plain
万方数据
维普
