Air preoxidation and Fe-catalyzed cooperative effect for preparation of high-performance coal-based granular activated carbon: Enhancing low-concentration CH4 recovery and utilization

Low-cost and efficient recovery of low-concentration CH4 is important in enhancing energy utilization and mitigating climate issues. The primary objective of this study was to develop a novel coal-based granular activated carbon through an improved preparation process. By utilizing anthracite as a precursor and coal tar as a binder, the present investigation highlights the cooperative effects of air preoxidation and Fe catalysis on the development and regulation of the pore structure in activated carbon. The efficiency of the modified activated carbon in separating CH4/N2 was tested and compared to that of commercial activated carbon. The modified activated carbon ACAFe exhibited an equilibrium separation factor of 3.23 for CH4/N2 at 25 °C. At 25 °C and 400 kPa, a single-column vacuum pressure swing adsorption (VPSA) process enriched CH4 from 40 mol% to 53.49 mol% and provided a CH4 recovery rate of 76.39%. ACAFe also demonstrated excellent cyclic regenerability. In conclusion, the cooperative effect of air preoxidation and Fe catalysis is an operationally simple, cost-effective, and highly efficient process with considerable industrial potential for recovering and utilizing low-concentration methane from unconventional natural gas sources.