Influence mechanism of trace K element on NO_x adsorption of coal-based carbon materials at low temperature

In this paper, Zhundong coal was used as the precursor of carbon material followed by activation by hydrothermal coupling with trace amount of K element. The influence of K concentration on the adsorption performance of as-prepared carbon material of NO_x at low temperature was studied. The experimental results showed that when the concentration of K₂CO₃ in the activation solution was 0.0067 g/mL, the sample had good NO_x adsorption performance, and the saturated NO_x adsorption time was 3200 s. The pore structure of the sample developed well with the specific surface area of 708.6 m²/g. The samples were characterized by XPS, SEM and the adsorption process was studied by FT-IR. It was found that excellent adsorption properties of Zhundong coal derived carbon material were related with the surface structure. DFT method was employed to verify the reaction mechanism. The results showed that K could promote the formation of C–O bond which was the key factor for promoting the NO_x adsorption. The best method and optimal process parameters for preparing Zhundong coal-based carbon materials by hydrothermal coupling with trace amount of K were obtained.