Activated carbons were synthesized from petroleum-based pitch and evaluated for the removal of trace siloxanes and hydrogen sulfide (H₂S) from gas streams. Oxidative stabilization followed by steam activation produced high specific surface area with enlarged mesoporosity (BET up to 1620.9 m² g⁻¹), as confirmed by N₂ sorption (BET/PSD), SEM, and elemental analysis. A GC/MS-based fixed-bed assay using 5 g of adsorbent, a 100 mL min⁻¹ challenge flow, and a 30 min readout was employed to quantify performance under consistent conditions. Under these tests, siloxanes were not detected at 30 min, and H₂S decreased to 0.38 ppm. Samples with greater mesopore volume while retaining high surface area showed higher 30 min removal. Surface-chemistry analysis indicated that oxygen functionalities introduced during stabilization facilitated pore development during subsequent steam activation without substantial loss of area. Taken together, the textural and adsorption results present a coherent picture in which a micro/mesopore architecture supports siloxane and H₂S control under the stated test conditions. The study records the key testing parameters and performance values to enable practical comparison of petroleum-pitch-derived activated carbons for gas purification.