The invention provides a process for removal of hydrogen sulphide, iron pentacarbonyl and nickel tetracarbonyl from a feed synthesis gas stream, the process comprising the steps of: (a) removal of hydrogen sulphide and of iron pentacarbonyl by contacting the feed synthesis gas stream with an absorbing liquid comprising water, physical solvent and an amine, to obtain a synthesis gas stream depleted of hydrogen sulphide and depleted of iron pentacarbonyl; (b) adsorption of nickel tetracarbonyl by contacting the synthesis gas stream depleted of hydrogen sulphide and depleted of iron pentacarbonyl with solid adsorbent comprising activated carbon to obtain solid adsorbent enriched in nickel tetracarbonyl and a purified synthesis gas stream.