Zhang Manlin, Yao Qingfeng, Lu Chao, Li Zenghe, Wang Wenxing
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
ACS Appl Mater Interfaces. 2014 Nov 26;6(22):20225-33. doi: 10.1021/am505765e. Epub 2014 Oct 23.
It would be of significance to design a green composite for efficient removal of contaminants. Herein, we fabricated a facile and environmentally friendly composite via direct assembly of surface passivated carbon dots with abundant oxygen-containing functional groups on the surface of the positively charged layered double hydroxide (LDH). The resulting LDH-carbon dot composites were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and N2 adsorption-desorption technique. The adsorption performances of the resulting LDH-carbon dot composites were evaluated for the removal of anionic methyl blue dye. Taking advantage of the combined benefits of LDH and carbon dots, the as-prepared composites exhibited high uptake capability of methyl blue (185 mg/g). The adsorption behavior of this new adsorbent fitted well with Langmuir isotherm and the pseudo-second-order kinetic model. The reasons for the excellent adsorption capacity of methyl blue on the surface of the LDH-carbon dot hybrid were further discussed. A probable mechanism was speculated to involve the cooperative contributions of hydrogen bonding between methyl blue and carbon dots and electrostatic attraction between methyl blue and LDH, in the adsorption process. This work is anticipated to open up new possibilities in fabricating LDH-carbon dot materials in dealing with anionic dye pollutants.
设计一种用于高效去除污染物的绿色复合材料具有重要意义。在此，我们通过将表面钝化的、具有丰富表面含氧官能团的碳点直接组装在带正电的层状双氢氧化物（LDH）表面，制备了一种简便且环境友好的复合材料。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱、高分辨率透射电子显微镜（HRTEM）、扫描电子显微镜（SEM）和N2吸附 - 脱附技术对所得的LDH - 碳点复合材料进行了表征。评估了所得LDH - 碳点复合材料对阴离子甲基蓝染料的吸附性能。利用LDH和碳点的综合优势，所制备的复合材料表现出对甲基蓝的高吸附能力（185 mg/g）。这种新型吸附剂的吸附行为与朗缪尔等温线和伪二级动力学模型拟合良好。进一步讨论了甲基蓝在LDH - 碳点杂化物表面具有优异吸附容量的原因。推测在吸附过程中，可能的机制涉及甲基蓝与碳点之间的氢键以及甲基蓝与LDH之间的静电吸引的协同作用。这项工作有望为制造用于处理阴离子染料污染物的LDH - 碳点材料开辟新的可能性。
