Department of Chemical Engineering, Faculty of Engineering, University of Kashan, Kashan, Iran E-mail:
School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), Tehran, Iran.
Water Sci Technol. 2021 Nov;84(9):2394-2405. doi: 10.2166/wst.2021.435.
In this research, natural bentonite and its acid-activated forms were employed as adsorbents for the adsorption of Ni ions from wastewater. Natural bentonite was activated with 2 M sulfuric acid, 4.5 h and 95 °C (the best acid-activated sample with the highest adsorption capacity) and the other 6 M sulfuric acid, 7.5 h and 95 °C (the worst acid-activated sample with the lowest adsorption capacity). The adsorption of Ni was studied through experiments including equilibrium contact time and selectivity. The equilibrium contact time for bentonite was obtained at 180 min. The Ni separation process along with Zn selectivity studies was considered through adsorption experiments. The results showed that there was a maximum amount of Ni adsorption in the absence of Zn for all samples. The results showed the best fit is obtained with the pseudo-second-order kinetic model. Working out different bentonite types to determine the best kinetic models, we explored the Langmuir and Florry-Huggins models provided a good fit with experimental data for acid-activated bentonites and the best results from linear forms of the adsorption isotherm models for fitting the experimental data of natural bentonite are obtained for Langmuir, Temkin and Freundlich models.
在这项研究中，天然膨润土及其酸化形式被用作吸附剂，从废水中吸附 Ni 离子。天然膨润土用 2 M 硫酸、4.5 小时和 95°C（吸附容量最高的最佳酸化样品）以及 6 M 硫酸、7.5 小时和 95°C（吸附容量最低的最差酸化样品）进行酸化。通过包括平衡接触时间和选择性在内的实验研究了 Ni 的吸附。膨润土的平衡接触时间为 180 分钟。通过吸附实验考虑了 Ni 分离过程以及 Zn 选择性研究。结果表明，对于所有样品，在没有 Zn 的情况下，Ni 的吸附量最大。结果表明，准二级动力学模型的拟合效果最好。通过探索不同的膨润土类型来确定最佳的动力学模型，我们发现对于酸化膨润土，Langmuir 和 Florry-Huggins 模型提供了与实验数据的良好拟合，而对于天然膨润土的实验数据，线性形式的吸附等温线模型中，Langmuir、Temkin 和 Freundlich 模型的拟合效果最好。
