Copper supported on activated carbon from hydrochar of pomelo peel for efficient H2S removal at room temperature: Role of copper valance, humidity and oxygen

•Porous activated carbon was obtained by KOH activation of pomelo peel hydrochar.•Cu0-loaded activated carbon has higher removal capacity than other copper species.•The desulfurization process involves catalytic oxidation and reactive adsorption.•Removal capacity under moist condition is higher than oxygen or nitrogen condition.•The terminated formation of sulphide and sulfate were earlier than elemental S.