College of Environmental Science & Engineering, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
J Hazard Mater. 2010 Aug 15;180(1-3):499-507. doi: 10.1016/j.jhazmat.2010.04.059. Epub 2010 Apr 20.
This paper reports on the development of organovermiculite-based adsorbent for removing Congo Red (CR), a model anionic dye, from aqueous solution. The organovermiculite was prepared using hexadecyl trimethylammonium bromide (HDTMAB) with variations in cation exchange capacity (CEC) and was then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results from the adsorption experiments showed that with the organic modification of 50, 100, and 200% CEC, the adsorption capacity of vermiculite towards CR was greatly improved from 2.6 to 74.07, 175.44 and 192.31 mg/g, respectively, at 298 K. The adsorption isotherm experiment was conducted at different temperatures (298, 308 and 318 K), and it was found that the uptake of CR increased with increasing temperature. Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to fit the equilibrium data better. The adsorption kinetics was found to follow the pseudo-second-order model. In addition, various thermodynamic parameters such as changes in enthalpy, entropy, and the Gibbs free energy were calculated, showing adsorption to be an endothermic yet spontaneous process. The results indicated that the organovermiculite may be an effective adsorbent for the removal of anionic dyes from wastewater.
本文报道了一种基于有机蛭石的吸附剂的开发，用于从水溶液中去除刚果红（CR），这是一种典型的阴离子染料。该有机蛭石是用十六烷基三甲基溴化铵（HDTMAB）制备的，其阳离子交换容量（CEC）有所变化，并用 X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）进行了表征。吸附实验结果表明，在 298 K 时，有机改性蛭石的 CEC 为 50%、100%和 200%时，对 CR 的吸附容量分别从 2.6 提高到 74.07、175.44 和 192.31mg/g。在不同温度（298、308 和 318 K）下进行了吸附等温线实验，发现 CR 的吸附量随温度升高而增加。应用了 Langmuir 和 Freundlich 等温模型，发现 Langmuir 模型更适合平衡数据。吸附动力学符合准二级模型。此外，还计算了各种热力学参数，如焓变、熵变和吉布斯自由能，表明吸附是一个吸热但自发的过程。结果表明，有机蛭石可能是一种从废水中去除阴离子染料的有效吸附剂。
