Reinforced nitrogen oxide gas adsorption by sulfur ionic treatment

To obtain a material that adsorbs nitrogen oxide (NO x ) gas with high efficiency, we used sulfuric acid (H 2 SO 4 )-treated activated carbon (AC). The proposed H 2 SO 4 -treated AC was treated by dipping and spray coating in a H 2 SO 4 solution. For structural analysis, scanning electron microscopy and Brunauer–Emmett–Teller measurements were performed on general and H 2 SO 4 -treated ACs. The composition of the atoms on the surface and inner pore structure of both ACs was confirmed through energy dispersive X-ray spectroscopy measurements. From the structural analysis, it was confirmed that the structure of H 2 SO 4 -treated AC was similar to that of general AC, indicating that it was not affected by the H 2 SO 4 solution. There was no significant difference in the inner pore structures of general and H 2 SO 4 -treated ACs through specific surface area analysis, which indicates that the physical adsorption of NO x gas for the H 2 SO 4 -treated AC is similar to that of general AC. Based on the atomic composition analysis, it was confirmed that sulfur ions were largely present on the inner pore structure than the surface of H 2 SO 4 -treated AC. These results indicate that the chemical adsorption of sulfur ions and NO x gas in the inner pore structure occurred rather than physical adsorption. The results of this study are expected to be applicable to the field of materials that remove harmful gases.