Stabilization and Steam Activation of Petroleum-Based Pitch-Derived Activated Carbons for Siloxane and H2S Gas Removal

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.