Nanophotonics and Applications Lab, Physics Department, Faculty of Science, Beni-Suef University, Salah Salm Street, Beni-Suef, 62514, Egypt.
Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt.
Environ Sci Pollut Res Int. 2017 Oct;24(29):22954-22966. doi: 10.1007/s11356-017-9942-0. Epub 2017 Aug 17.
Raw kaolinite was used in the synthesis of metakaolinite/carbon nanotubes (K/CNTs) and kaolinite/starch (K/starch) nanocomposites. Raw kaolinite and the synthetic composites were characterized using XRD, SEM, and TEM techniques. The synthetic composites were used as adsorbents for Fe and Mn ions from aqueous solutions and natural underground water. The adsorption by the both composites is highly pH dependent and achieves high efficiency within the neutral pH range. The experimental adsorption data for the uptake of Fe and Mn ions by K/CNTs were found to be well represented by the pseudo-second-order kinetic model rather than the intra-particle diffusion model or Elovich model. For the adsorption using K/starch, the uptake results of Fe ions was well fitted by the second-order model, whereas the uptake of Mn ions fitted well to the Elovich model rather than pseudo-second-order and intra-particle diffusion models The equilibrium studies revealed the excellent fitting of the removal of Fe and Mn ions by K/CNTs and Fe using K/starch with the Langmuir isotherm model rather than with Freundlich and Temkin models. But the adsorption of Mn ions by K/starch is well fitted with Freundlich rather than Temkin and Langmuir isotherm models. The thermodynamic studies reflected the endothermic nature and the exothermic nature for the adsorption by K/CNTs and K/starch nanocomposites, respectively. Natural ground water contaminated by 0.4 mg/L Fe and 0.5 mg/L Mn was treated at the optimum conditions of pH 6 and 120 min contact time. Under these conditions, 92.5 and 72.5% Fe removal efficiencies were achieved using 20 mg of K/CNTs and K/starch nanocomposites, respectively. Also, K/CNTs nanocomposite shows higher efficiency in the removal of Mn ions as compared to K/starch nanocomposite.
高岭土原土被用于介孔偏高岭土/碳纳米管（K/CNTs）和高岭土/淀粉（K/Starch）纳米复合材料的合成。使用 XRD、SEM 和 TEM 技术对高岭土原土和合成复合材料进行了表征。将合成复合材料用作从水溶液和天然地下水中吸附 Fe 和 Mn 离子的吸附剂。这两种复合材料的吸附均高度依赖 pH 值，在中性 pH 范围内效率很高。用 K/CNTs 吸附 Fe 和 Mn 离子的实验吸附数据通过准二级动力学模型得到了很好的表示，而不是通过内扩散模型或 Elovich 模型。对于 K/Starch 的吸附，Fe 离子的吸附结果与二级模型拟合较好，而 Mn 离子的吸附与 Elovich 模型拟合较好，而不是准二级和内扩散模型。平衡研究表明，K/CNTs 和 K/Starch 对 Fe 和 Mn 离子的去除与 Langmuir 等温线模型拟合较好，而与 Freundlich 和 Temkin 模型拟合较差。但是，K/Starch 对 Mn 离子的吸附与 Freundlich 模型拟合较好，而不是 Temkin 和 Langmuir 等温线模型。热力学研究反映了 K/CNTs 和 K/Starch 纳米复合材料吸附的吸热和放热特性。用 pH 值为 6 和接触时间为 120min 的最佳条件处理受 0.4mg/L Fe 和 0.5mg/L Mn 污染的天然地下水。在这些条件下，用 20mg 的 K/CNTs 和 K/Starch 纳米复合材料分别实现了 92.5%和 72.5%的 Fe 去除效率。此外，K/CNTs 纳米复合材料在去除 Mn 离子方面比 K/Starch 纳米复合材料更有效。
