Trgo M, Perić J, Medvidović N Vukojević
University of Split, Faculty of Chemical Technology, Teslina 10/V, 21000 Split, Croatia.
J Hazard Mater. 2006 Aug 25;136(3):938-45. doi: 10.1016/j.jhazmat.2006.01.032. Epub 2006 Feb 28.
The kinetics of zinc and lead ions removal by modified zeolite-clinoptilolite has been investigated. The rate of the ion exchange process for lead ions is faster than for zinc ions, as well as the time needed to reach the equilibrium. The ion exchange capacity of zeolite of lead ions is doubly higher than that of zinc ions. Diffusion models according to the Vermeulen's approximation, the parabolic diffusion model and the homogeneous diffusion model have been tested with the experimental data of ion exchange for zinc and lead. For both systems examined, the best fit of the models proposed with the experimental data was shown by the Vermeulen's approximation and the homogeneous diffusion model with t-->t(infinity). The diffusion coefficients are calculated from kinetic models of lead ions they are of the order of 10(-6)cm(2)/min, constant for all examined initial concentrations and not dependent on time. The diffusion coefficients in the system of zinc ions is of the order of 10(-8)cm(2)/min, also independent of initial concentrations, but decreasing with time from the beginning of ion exchange to the equilibrium.
研究了改性斜发沸石-斜发沸石去除锌离子和铅离子的动力学。铅离子的离子交换过程速率比锌离子快，达到平衡所需的时间也比锌离子短。沸石对铅离子的离子交换容量是锌离子的两倍。根据弗尔梅伦近似、抛物线扩散模型和均匀扩散模型的扩散模型已用锌和铅的离子交换实验数据进行了测试。对于所研究的两个系统，所提出的模型与实验数据的最佳拟合由弗尔梅伦近似和t→t(∞)时的均匀扩散模型给出。从铅离子的动力学模型计算出扩散系数，其量级为10(-6)cm(2)/min，对于所有研究的初始浓度都是常数，且与时间无关。锌离子系统中的扩散系数量级为10(-8)cm(2)/min，也与初始浓度无关，但从离子交换开始到平衡随时间减小。
