Chinese Journal of Chemical Engineering ›› 2020, Vol. 28 ›› Issue (6): 1694-1700.doi: 10.1016/j.cjche.2019.12.017

• Energy, Resources and Environmental Technology • Previous Articles     Next Articles

CO2-hierarchical activated carbon prepared from coal gasification residue: Adsorption equilibrium, isotherm, kinetic and thermodynamic studies for methylene blue removal

Yuhong Kang1,2, Xianyong Wei1,2, Guanghui Liu1, Miao Mu2, Xiangrong Ma1,2, Yong Gao1,2, Zhimin Zong1   

  1. 1 Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China;
    2 Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization, School of Chemistry and Chemical Engineering, Yulin University, Yulin, Shaanxi 71900, China
  • Received:2019-07-16 Revised:2019-12-08 Online:2020-06-28 Published:2020-07-29
  • Contact: Xianyong Wei
  • Supported by:
    The authors greatfully acknowledged for the financial support from the National Natural Science Foundation of China (51762042), the (2019PT-18), the Science and Technology Program of Shaanxi Province (2017GY-136; 2018GY-086) and the Shaanxi Province Education Department Key Scientific Research Project (18JS123)

Abstract: Mineral matter in a residue (RCG) from coal gasification (CG) was removed by two-stage acid leaching. Hierarchical activated carbon (HAC) was prepared by activating RCG with CO2. The performance of HAC on removing methylene blue (MB) from an aqueous solution was investigated. HAC was characterized by N2 adsorption-desorption isotherm, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results show that HAC exhibits hierarchical pore structure with high specific surface area (862.76 m2·g-1) and total pore volume (0.684 cm3·g-1), and abundant organic functional groups. The adsorption equilibrium data of MB on HAC are best fitted to the Redlich-Peterson. The kinetic data show that the pseudo-first-order model is more suitable at low MB concentration, while the advantages of the pseudo-second-orderand the Elovich models are more obvious as the concentration increases. According to the thermodynamic parameters, the HAC-MB adsorption process is spontaneous and endothermic.

Key words: Residue from coal gasification, Hierarchical activated carbon, Physical activation, Adsorption models