High-efficiency adsorption of Cr(VI) and RhB by hierarchical porous carbon prepared from coal gangue

Coal gangue (CG) is one of the largest industrial solid wastes in the world produced during the process of coal mining. The accumulation of CG is easy to cause ion leakage, which is harmful to the environment and human body. The recovery and utilization of CG are imminent. In the process, a hierarchical porous carbon (HPC) adsorbent with excellent adsorption property for Cr(VI) and rhodamine B (RhB), was prepared from CG by a two-step method and characterized by SEM, TEM, XRD, XPS, TPD and BET. The results revealed that the specific surface area of HPC is up to 2012.7 m2 g−1, and its adsorption capacities for Cr(VI) and RhB are reached 320.51 and 3086.42 mg g−1. The adsorption mechanism of RhB was the synergetic effect of physics and chemistry. While XPS results suggested that hierarchical porous carbons (HPCs) only have a chemisorption effect on Cr(VI). This study provided an idea for the preparation of HPCs from CG to remove inorganic and organic pollutants such as heavy metal Cr(VI) and RhB in water.