Akçay Mehmet
Department of Chemistry, Faculty of Science and Art, University of Dicle, TR 21280, Diyarbakir, Turkey.
J Colloid Interface Sci. 2006 Apr 1;296(1):16-21. doi: 10.1016/j.jcis.2005.08.031. Epub 2005 Oct 4.
The montmorillonite has been subjected to modification through ion-exchange reaction by tetrabutylammonium bromide (TBAB). The modified sample was studied by X-ray diffraction (XRD) technique, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA) methods. The basal spacing of modified montmorillonite was determined as 14.40 A. The IR spectra of modified montmorillonite showed CH vibrations. The characterization of tetrabutylammonium montmorillonite (TBAM) and the adsorption of p-chlorophenol (p-CP) on organomontmorillonite was studied as a function of the solution concentration and temperature. The observed adsorption rates were found to fit to the pseudo-second-order kinetics. The rate constants were calculated for temperatures ranging between 25.0-35.0 degrees C at constant concentration. The adsorption energy, E, and adsorption capacity, (q(m)), for phenolic compounds adsorbing on organomontmorillonite were estimated using the Dubinin-Radushkevich (D-R) equation. Thermodynamic parameters (delta g(a) = -11.063 and -11.802 kJ/mol, delta h(a) = -30.032 and -30.789 kJ/mol, delta s(a) = -0.0636 and -0.0637 kJ/mol K for 298 and 308 K, respectively) were calculated by a new approximation from the adsorption isotherms of p-CP on organomontmorillonite. These isotherms were modeled according to Freundlich and Dubinin-Radushkevich adsorption isotherms, through which the first-order and second-order coefficients (K(1ads) = 0.0152 and 0.0127 micromol/g min, K(2ads) = 0.0130 and 0.0108 L/min micromol, respectively) were obtained at 298 and 308 K.
蒙脱石已通过溴化四丁铵（TBAB）进行离子交换反应改性。采用X射线衍射（XRD）技术、傅里叶变换红外（FTIR）光谱和热重分析（TGA）方法对改性样品进行了研究。改性蒙脱石的层间距测定为14.40 Å。改性蒙脱石的红外光谱显示有CH振动。研究了四丁铵蒙脱石（TBAM）的表征以及对氯苯酚（p-CP）在有机蒙脱石上的吸附与溶液浓度和温度的关系。观察到的吸附速率符合准二级动力学。在恒定浓度下，计算了25.0 - 35.0℃温度范围内的速率常数。利用Dubinin-Radushkevich（D-R）方程估算了酚类化合物在有机蒙脱石上的吸附能E和吸附容量（q(m)）。通过对p-CP在有机蒙脱石上的吸附等温线采用新的近似方法计算了热力学参数（298 K和308 K时，ΔG(a)分别为 - 11.063和 - 11.802 kJ/mol，ΔH(a)分别为 - 30.032和 - 30.789 kJ/mol，ΔS(a)分别为 - 0.0636和 - 0.0637 kJ/mol K）。这些等温线根据Freundlich和Dubinin-Radushkevich吸附等温线进行建模，在298 K和308 K时分别得到一级和二级系数（K(1ads)分别为0.0152和0.0127 μmol/g·min，K(2ads)分别为0.0130和0.0108 L/min·μmol）。
