Tsai W T, Lai C W, Hsien K J
Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan.
Chemosphere. 2004 May;55(6):829-37. doi: 10.1016/j.chemosphere.2003.11.043.
In the present study, the activated bleaching earth was used as adsorbent for the herbicide paraquat adsorption in a batch adsorber. The rate of adsorption has been investigated under the controlled process parameters like agitation speed, initial paraquat concentration, adsorbent dosage and temperature. A batch kinetic model, based on the assumption of 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 fittings of the experimental data. The results of the kinetic studies show that the adsorption process can be well described with the pseudo-second order equation. Based on the isotherm data obtained from the fittings of the adsorption kinetics, Freundlich model appears to fit the adsorption better than Langmuir model. In addition, the effective diffusion coefficient has also been estimated based on the restrictive diffusion model.
在本研究中，活性漂白土被用作吸附剂，在间歇式吸附器中吸附除草剂百草枯。在搅拌速度、百草枯初始浓度、吸附剂用量和温度等可控工艺参数下研究了吸附速率。基于准二级反应机理假设的间歇动力学模型，通过对实验数据的拟合，用于预测吸附速率常数、平衡吸附容量、半吸附时间和平衡浓度。动力学研究结果表明，吸附过程可以用准二级方程很好地描述。根据吸附动力学拟合得到的等温线数据，Freundlich模型似乎比Langmuir模型更适合该吸附过程。此外，还基于限制性扩散模型估算了有效扩散系数。
