Chang C Y, Tsai W T, Ing C H, Chang C F
Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan, ROC.
J Colloid Interface Sci. 2003 Apr 15;260(2):273-9. doi: 10.1016/s0021-9797(02)00174-1.
In the present study, a hydrophobic zeolite was used as an adsorbent for the adsorption of polyethylene glycol (PEG) in water solution and electroplating solution at 25 degrees C. The adsorption capacities were determined through the adsorption isotherms in a thermostated shaker. The rate of adsorption, on the other hand, was investigated in a batch adsorber under controlled process parameters such as initial PEG concentration (30, 70, 110, 150, 200, and 300 mg x dm(-3)), agitation speed (200, 800, and 1000 rpm), and adsorbent particle size (0.72, 1.44, and 2.03 mm). A batch kinetic model, according to a pseudo-second-order mechanism, has been tested to predict the rate constant of adsorption, equilibrium adsorption capacity, time of half-adsorption, and equilibrium concentration by the fitting of the experimental data. The results of the adsorption isotherm and kinetic studies show that the adsorption process can well be described with the Langmuir and Freundlich models and the pseudo-second-order equation, respectively. Comparing the values of adsorption parameters of PEG in water solution and electroplating solution, there are no significant differences. In addition, the effective diffusion coefficient of the PEG molecule in the microporous adsorbent has been estimated at about 3.20 x 10(-8) cm(2)s(-1) based on the restrictive diffusion model.
在本研究中，一种疏水性沸石被用作吸附剂，用于在25摄氏度下吸附水溶液和电镀液中的聚乙二醇（PEG）。吸附容量通过在恒温振荡器中的吸附等温线来测定。另一方面，吸附速率是在间歇式吸附器中，在诸如初始PEG浓度（30、70、110、150、200和300 mg·dm⁻³）、搅拌速度（200、800和1000 rpm）以及吸附剂粒径（0.72、1.44和2.03 mm）等受控工艺参数下进行研究的。根据拟二级动力学机制的间歇动力学模型，通过拟合实验数据来预测吸附速率常数、平衡吸附容量、半吸附时间和平衡浓度。吸附等温线和动力学研究结果表明，吸附过程分别可以用朗缪尔模型和弗伦德利希模型以及拟二级方程很好地描述。比较PEG在水溶液和电镀液中的吸附参数值，没有显著差异。此外，基于限制扩散模型，估计PEG分子在微孔吸附剂中的有效扩散系数约为3.20×10⁻⁸ cm²·s⁻¹。
