Biogas is a common renewable energy resource. A very important stage of biogas upgrading, studied in the present work, is its purification from H2S traces. The selective absorption of H2S and CO2 into oxido-alkaline solutions containing hydrogen peroxide and into amine solutions was compared by performing absorption test runs in a cables-bundle scrubber at 293.15 K and atmospheric pressure. The absorption rate and selectivity for H2S over CO2 were determined for various solute partial pressures, different alkaline absorbents and hydrogen peroxide concentrations in the scrubbing liquid, and different pH values. Higher H2S-selective absorption performances with oxido-alkaline solutions than with amine solutions could be observed provided that the solution is at a low pH value (9.5) and contains a sufficient hydrogen peroxide concentration.