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研究了高岭石、针铁矿及其混合物(KGM)和复合物(KGC)的表面性质及吸附胡敏酸的特性.结果表明,4种物质的比表面积(SSA)表现为针铁矿>KGC>KGM>高岭石,KGM的SSA接近两种纯物质的平均值,而KGC的SSA明显升高.高岭石、针铁矿、KGM和KGC的等电点(IEP)分别为3.2、7.9、6.1和6.7;初始p H=5.0时,其表面Zeta电位分别为-13.9、38.2、14.3和19.7 m V.4种样品对胡敏酸的动力学吸附过程适合用准二级动力学模型描述,表明化学吸附是主要作用机制.一、二位Langmuir模型可较好地拟合等温吸附数据(R~2为0.962~0.993),其中二位Langmuir模型对KGM和KGC吸附数据的拟合度R~2分别为0.989和0.993;Freundlich模型对等温吸附数据的拟合度较低,但两种二元体的拟合度高于两种纯物质.初始p H=5.0时,高岭石、针铁矿、KGM和KGC对胡敏酸的吸附容量(q_(max))分别为6.02、61.83、35.13和42.10 mg·g~(-1);两种二元体的q_(max)都高于两种纯物质q_(max)的平均值,其中KGC的q_(max)明显升高.热力学参数表明,4种样品对胡敏酸的吸附均属于吸热反应,其中高岭石的吸附为非自发过程,其余样品的吸附为自发过程.
The surface properties of kaolinite, goethite and their mixtures (KGM) and complexes (KGC) and the properties of adsorbed humic acid were studied.The results showed that the specific surface area (SSA) of four materials was goethite> KGC> KGM> kaolinite, the SSA of KGM is close to the average value of two pure substances, while the SSA of KGC is obviously increased.The isoelectric point (IEP) of kaolinite, goethite, KGM and KGC are 3.2, 7.9, 6.1 and 6.7, respectively. The initial zeta potential of pH = 5.0 was -13.9, 38.2, 14.3 and 19.7 mV, respectively. The kinetic adsorption of humic acid by four samples was suitable for quasi-second order kinetic model , The chemical adsorption is the main mechanism.The first and second Langmuir models fit well the isothermal adsorption data (R ~ 2 = 0.962 ~ 0.993), and the two-position Langmuir model has good agreement with the KGM and KGC adsorption data R ~ 2 were 0.989 and 0.993, respectively, while the fitting degree of Freundlich model was lower for the isotherm data, but the fitting degree of the two binders was higher than that of the two pure materials.When initial p H = 5.0, kaolinite, The adsorption capacity (g_ (max)) of goethite, KGM and KGC for the humic acid were 6.02, 61.83, 35.13 and 42.10 mg · g -1, respectively. The q_ (max) In two pure The q_ (max) average value of qCmax of KGC was significantly higher than that of KGC.The thermodynamic parameters indicated that the adsorption of humic acid belongs to the endothermic reaction, and the sorption of kaolinite is a non-spontaneous process, The adsorption of the remaining samples was spontaneous.