Department of Materials Science and Engineering, and Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
Department of Organic Materials and Fiber Engineering, Soongsil University, 369 Sangdo-ro, Dongjak-gu, Seoul 06978, South Korea.
J Environ Manage. 2018 Jan 15;206:740-748. doi: 10.1016/j.jenvman.2017.10.051. Epub 2017 Nov 20.
We develop mesoporous magnetic clusters (MMCs) functionalized with hydrophilic branched polyethylenimine (b-PEI), later called b-MG, and MMCs functionalized with positively charged b-PEI (p-MG). These materials efficiently remove Pb(II) and Cr(VI) from wastewater. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and nitrogen adsorption-desorption analysis results clearly indicate that hydrophilic b-PEI and positively charged b-PEI are successfully attached to the MMC surfaces. Wide-angle X-ray diffraction, high-resolution transmission electron microscopy, and field-emission scanning electron microscopy analyses confirm that the crystal structures and morphologies of the MMCs are maintained well even when wet chemical modification processes are used to introduce hydrophilic b-PEI and positively charged b-PEI to the MMC surfaces. Langmuir and Sips isotherm models are applied to describe Pb(II) adsorption behavior of the b-MG and Cr(VI) adsorption behavior of the p-MG. The isotherm models indicate that the maximum adsorption capacities of b-MG and p-MG, respectively, are 216.3 and 334.1 mg g, respectively. These are higher than have previously been found for other adsorbents. In reusability tests, using magnetic separation and controlling the pH, the Pb(II) recovery efficiency of the b-MG is 95.6% and the Cr(VI) recovery efficiency of the p-MG is 68.0% even after the third cycle.
我们制备了功能化的介孔磁性纳米簇（MMC），其表面接枝有亲水性的支化聚乙烯亚胺（b-PEI），简称 b-MG，以及带正电荷的 b-PEI（p-MG）。这些材料能有效地从废水中去除 Pb(II) 和 Cr(VI)。傅里叶变换红外光谱、X 射线光电子能谱、热重分析和氮气吸附-脱附分析结果清楚地表明，亲水性的 b-PEI 和带正电荷的 b-PEI 已成功地接枝到 MMC 表面。广角 X 射线衍射、高分辨率透射电子显微镜和场发射扫描电子显微镜分析证实，即使在使用湿化学修饰过程将亲水性 b-PEI 和带正电荷的 b-PEI 引入 MMC 表面时，MMC 的晶体结构和形貌也能很好地保持。Langmuir 和 Sips 等温吸附模型分别被用来描述 b-MG 对 Pb(II)的吸附行为和 p-MG 对 Cr(VI)的吸附行为。这些等温吸附模型表明，b-MG 和 p-MG 的最大吸附容量分别为 216.3 和 334.1 mg g-1，高于之前报道的其他吸附剂。在可重复使用性测试中，通过磁分离并控制 pH 值，b-MG 对 Pb(II)的回收效率为 95.6%，p-MG 对 Cr(VI)的回收效率为 68.0%，即使在第三次循环后也是如此。
