Hierarchically porous carbon derived from metal-organic frameworks for separation of aromatic pollutants
Hierarchically porous carbon derived from metal-organic frameworks for separation of aromatic pollutants
复制标题
用于分离芳香族污染物的金属有机骨架衍生的多级多孔碳
DOI：
10.1016/j.cej.2018.04.051
复制
发表时间：
2018
影响因子：
15.1
通讯作者：
Zhang Wei-xian
中科院分区：
文献类型：
--
作者：
Teng Wei;Bai Nan;Chen Zehan;Shi Junming;Fan Jianwei;Zhang Wei-xian
多孔碳是有机污染物分离处理中最重要、最常用的吸附剂。任何吸附剂都需要具有可接近的大表面积、物理和化学稳定性以及低成本的制造方法等特性。本文通过对结晶金属有机骨架（MOF-5）的热解和石墨化制备了层次化多孔碳（HPC），以增强对芳香族污染物的吸附。经过高温（950 °C）处理的材料具有大表面积（1512 m2/g），高孔隙率（0.94 cm3/g）和分层多孔结构。生成的4 nm左右的介孔提高了微孔和大孔的连通性，使多孔材料成为吸附有机污染物（如芳烃）的理想材料。研究了吸附剂剂量、pH、离子强度、接触时间和初始浓度对对硝基苯酚（PNP）吸附的影响。吸附等温线和动力学表明，吸附是一个自发的吸热吸附过程，具有单层表面覆盖。石墨层对芳香环的π电子有很高的亲和力，因此表面位置富含电子。层次化多孔活性炭（HPC）的吸附能力比传统活性炭高出近100%。
Porous carbon is the most important and most common adsorbent for the separation and treatment of organic pollutants. Characteristics such as accessible and large surface area, physical and chemical stability, and low-cost manufacturing method are desired for any adsorbent. Herein, a hierarchically porous carbon (HPC) was prepared by pyrolysis and graphitization of crystalline metal–organic frameworks (MOF-5) for enhanced adsorption of aromatic contaminants. The material treated at high temperature (950 °C) possesses large surface area (1512 m2/g), high porosity (0.94 cm3/g), and hierarchically porous structures. The generated mesopores around 4 nm improve the interconnectivity of micro- and macropores to make the porous material ideal for sorption of organic pollutants such as aromatic hydrocarbons. Effects of adsorbent dose, pH, ionic strength, contact time, and initial concentration on the adsorption ofp-nitrophenol (PNP, as a model) were investigated. Adsorption isotherms and kinetics suggest that the adsorption is a spontaneous and endothermic physisorption process with monolayer surface coverage. The surface sites are electron-rich due to the graphitic layer, which has high affinity toward π electrons of the aromatic ring. The adsorption capacity of the hierarchically porous carbon (HPC) is nearly over 100% higher that of conventional activated carbon.