用于去除有机染料的分级结构ZnO微球的简便合成

Simple synthesis of hierarchical ZnO microspheres for organic dyes removal

以六亚甲基四胺(HMTA)为结构导向剂,采用乙二醇辅助的溶剂热法制备了均匀分散的纳米片组装的三维分级结构ZnO微米球。可控实验证明,HMTA和溶剂在分级结构微米球的形成中起重要作用。通过二维纳米片组装来构建三维分级结构,不仅增加了产品的比表面积,而且还建立了更多的电荷传输通道。在暗室下,该样品可作为吸附剂去除水溶液中的一些有机染料。吸附结果表明,纳米片组装的分级结构ZnO微球对阴离子染料具有良好的去除率和选择性。特殊的分级结构、较大的比表面积和静电引力的协同作用,使ZnO微球对代表性染料刚果红(CR)经过5次循环吸附后的去除率仍可达95.67%。动力学研究证实,CR在ZnO微球上的吸附为物理吸附,符合准二级动力学和Langmuir等温线模型。

Uniform and dispersed 3D hierarchical nanosheets-assembled ZnO microspheres were fabricated by a simple ethylene glycol(EG)-assisted solvothermal route,in which hexamethylenetetramine(HMTA)was selected as a functional agent.A series of controllable experiments proved that HMTA and the solvent play vital roles in the formation of hierarchical microspheres.The assembly of 2D nanosheets to construct the 3D hierarchical structures not only increases the specific surface area of the products but also builds more charge transport channels.The samples were evaluated as adsorbents for the removal of some organic dyes from the aqueous solution in dark.Resultantly,the hierarchical nanosheets-assembled ZnO microspheres showed excellent removal rate and selectivity for anionic dyes.Taking Congo red(CR)as a representative dye,it can be removed 95.67%after five adsorption cycles due to the synergistic effects of hierarchical structures,large surface areas,and electrostatic attraction.The kinetics studies confirmed that the adsorption of CR onto ZnO microspheres is physisorption and followed the pseudo-second-order kinetic and Langmuir isotherm models.