Physically (steam) and chemically (KOH) activated carbons prepared from Luscar coal and biochar were used for removal of low concentrations of hydrogen sulphide (1 mol%) in methane. A modification method including acid treatment and thermal desorption in an inert atmosphere was used and the effects of this modification on the porous structure, surface chemistry, and ash content were studied. It increased total pore volume of activated carbons prepared from coal and biochar by 43% and 11%, respectively. Acid treatment changed the surface chemistry of activated carbons. Also, thermal desorption removed most of the acidic groups, especially carboxylic groups. The break-through times corresponding to 80% removal of H2S using modified activated carbons prepared from coal and biochar were increased to 102 and 131 min, respectively. Also, the production of SO2 as an undesirable by-product was less than 1.9% of H2S fed into the reactor.