The invention relates to a process for removing and recovering mercury, an impurity, from a hydrocarbon feedstream containing oxygen, such as introduced during hydraulic fracturing. Mercury is selectively removed to very low levels of concentration from fluid streams such as natural gas, cracked gas, hydrogen or naphtha by passage of the stream through an adsorbent bed containing particles of a zeolitic molecular sieve preferably having pore diameters of at least 3.0 angstroms and in which the zeolite crystallites are formed into an aggregate (cylindrical or beads) which contain ionic or elemental silver. These adsorbent particles maintain their capacity for removal of mercury despite the presence of oxygen.