This study presents the adsorption of sulfate by clinoptilolite and magnetic nanotubes (MNT) from the Gamasiab river (Kermanshah, Iran) samples. The samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results showed that selective methods were implemented properly for nanoparticle preparation. During the process operating, time was considered as the most significant factor in sulfate removal. Moreover, adsorbent to pollutant ratios (D/C), and pH was selected as control variables. The design of the experiment was used to find the optimal conditions for the use of adsorbents. The optimum adsorption points were obtained for the MNT at pH 8.97 and D/C = 6.12 and the clinoptilolite at pH 10.68 and D/C = 22.07. The effect of pH on the adsorbents indicated that the adsorbent performance in the alkaline condition has the highest efficiency. Hence, for MNTs, increasing pH value increased the adsorbance amount. To investigate the effect of D/C, the rate of adsorption showed an ascending trend. In addition, the equilibrium data were defined by Langmuir and Freundlich isotherm models, respectively. Freundlich isotherm well described the process of adsorbing sulfate by clinoptilolite with a correlation coefficient of 0.918. While the Langmuir isotherm was consistent with the adsorption process of sulfate by MNT with a correlation coefficient of 0.9728. The efficiency of sulfate adsorption for clinoptilolite and MNT in the natural river samples was calculated 91.5% and 97.8%, respectively. The results showed the superiority of MNT adsorption capability in river water conditions.

中文翻译：

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改性斜发沸石和磁性纳米管去除硫酸盐的性能评估及在天然河流样品中的潜在应用

本研究展示了来自 Gamasiab 河（伊朗克尔曼沙赫）样品的斜发沸石和磁性纳米管 (MNT) 对硫酸盐的吸附。样品已通过 X 射线衍射 (XRD)、透射电子显微镜 (TEM) 和傅里叶变换红外光谱 (FT-IR) 进行表征。结果表明，纳米颗粒制备的选择性方法得到了适当的实施。在工艺操作过程中，时间被认为是去除硫酸盐的最重要因素。此外，吸附剂与污染物的比率 (D/C) 和 pH 值被选为控制变量。实验设计用于寻找使用吸附剂的最佳条件。MNT 在 pH 8.97 和 D/C = 6.12 和斜发沸石在 pH 10.68 和 D/C = 22.07 时获得了最佳吸附点。pH 值对吸附剂的影响表明，在碱性条件下的吸附性能具有最高的效率。因此，对于 MNTs，增加 pH 值会增加吸附量。为了研究 D/C 的影响，吸附速率呈上升趋势。此外，平衡数据分别由 Langmuir 和 Freundlich 等温模型定义。Freundlich 等温线很好地描述了斜发沸石吸附硫酸盐的过程，相关系数为 0.918。而朗缪尔等温线与 MNT 吸附硫酸盐的过程一致，相关系数为 0.9728。计算得出，天然河流样品中斜发沸石和 MNT 的硫酸盐吸附效率分别为 91.5% 和 97.8%。