A process and apparatus wherein an adsorption media, containing contaminants adsorbed from a contaminated gas stream, are contained in a media chamber. This chamber is defined by a generally cylindrical vessel, and the adsorption media comprises a polymeric material in particulate or bead form. The media chamber is defined in surrounding relationship to an elongate hollow guide tube which extends longitudinally along the central axis of the chamber. A microwave generator supplies microwave energy into the guide tube which functions as a waveguide. This waveguide has a plurality of slots formed therein which functions as radiators for the microwave energy. The microwave energy passes radially outwardly from the waveguide into the surrounding media throughout the length thereof to effect uniform heating of the media both longitudinally and radially. This heating effects release of the contaminants from the adsorbent media, which volatiles are then sucked out of the media.