Qiu Tian, Yang Jian-Guo, Bai Xue-Jie, Wang Yu-Ling
National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology Xuzhou Jiangsu 221116 China
School of Chemical Engineering and Technology, China University of Mining and Technology Xuzhou Jiangsu 221116 China.
RSC Adv. 2019 Apr 25;9(22):12737-12746. doi: 10.1039/c9ra00343f. eCollection 2019 Apr 17.
Herein, synthetic graphite materials with hierarchical pores and large specific surface area were successfully prepared by one-step impregnation with lignite as the carbon source, sulfuric acid (HSO) as the oxidant, and phosphoric acid (HPO) as the activator. The microstructural characteristics of synthetic graphite were investigated X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Moreover, the pore parameters were studied by nitrogen adsorption-desorption. The results showed that synthetic graphite had a perfect orderly layered structure with high graphitization degree and a well-developed multistage pore structure with pore sizes ranging from nanometer to micrometer. The specific surface area and pore volume were 415.29 m g and 0.67 cm g, respectively. The results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that the impregnation pretreatment provided polar groups containing oxygen to the surfaces. These unique characteristics make synthetic graphite possess good adsorption capacity for dye pollutants (the adsorption rate of the methyl orange solution was 99.9% within 60 min at 50 °C, and the pH value of the solution was 3). The effects of temperature and pH value on the adsorption capacity were studied. The repeatability of the adsorption performance was also tested, and the adsorption rate was 84.6% of the initial adsorption rate after five cycles.
在此，以褐煤为碳源、硫酸（H₂SO₄）为氧化剂、磷酸（H₃PO₄）为活化剂，通过一步浸渍法成功制备了具有分级孔隙和大比表面积的合成石墨材料。利用X射线衍射（XRD）、拉曼光谱、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了合成石墨的微观结构特征。此外，通过氮气吸附-脱附研究了孔隙参数。结果表明，合成石墨具有完美的有序层状结构，石墨化程度高，且具有发达的多级孔隙结构，孔径范围从纳米到微米。比表面积和孔体积分别为415.29 m²/g和0.67 cm³/g。傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）结果表明，浸渍预处理为表面提供了含氧极性基团。这些独特的特性使合成石墨对染料污染物具有良好的吸附能力（在50℃下60分钟内甲基橙溶液的吸附率为99.9%，溶液pH值为3）。研究了温度和pH值对吸附容量的影响。还测试了吸附性能的重复性，五个循环后吸附率为初始吸附率的84.6%。
