Kinetic and equilibrium studies in removing lead ions from aqueous solutions by natural sepiolite.
Kinetic and equilibrium studies in removing lead ions from aqueous solutions by natural sepiolite.
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DOI：
10.1016/j.jhazmat.2004.04.015
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发表时间：
2004-08
影响因子：
13.6
通讯作者：
N. Bektaş;Burcu Akman Ağim;S. Kara
中科院分区：
文献类型：
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作者：
N. Bektaş;Burcu Akman Ağim;S. Kara
在不同的实验条件下，研究了海泡石对水溶液中铅离子的去除能力。朗缪尔和Freundlich方程，这是常用的用于描述吸附平衡的废水处理应用程序，被施加到数据。计算并比较了该体系在不同pH、温度和粒径条件下的等温线模型常数和相关系数。吸附平衡过程符合Langmuir吸附等温式，在最佳实验条件下，最大吸附量为93.4mg/g。由温度关系确定了铅在海泡石上吸附的热力学参数（ΔG°、ΔH°和ΔS°）。具体参数的影响，如搅拌速度，粒度和初始浓度的动力学研究进行了检查。采用一级可逆反应、准一级反应和准二级反应对吸附动力学进行了测试，并计算了动力学模型的速率常数。采用准二级动力学模型得到的相关系数最好，表明铅的吸收过程符合准二级动力学方程。
The capacity of sepiolite for the removal of lead ions from aqueous solution was investigated under different experimental conditions. The Langmuir and Freundlich equations, which are in common use for describing sorption equilibrium for wastewater-treatment applications, were applied to data. The constants and correlation coefficients of these isotherm models for the present system at different conditions such as pH, temperature and particle size were calculated and compared. The equilibrium process was well described by the Langmuir isotherm model and the maximum sorption capacity was found to be 93.4mg/g for the optimal experimental condition. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) for lead sorption on the sepiolite were also determined from the temperature dependence. The influences of specific parameters such as the agitation speed, particle size and initial concentration for the kinetic studies were also examined. The sorption kinetics were tested for first order reversible, pseudo-first order and pseudo-second order reaction and the rate constants of kinetic models were calculated. The best correlation coefficients were obtained using the pseudo-second order kinetic model, indicating that lead uptake process followed the pseudo-second order rate expression.