The invention permits, without the consumption of energy, emission of negative ions to purify the environment. In addition, the invention has biocidal action to eliminate microorganisms and bacteria. Furthermore, the invention emits infrared radiation to dry out walls, ceilings and objects in the room, thereby removing moisture. To those ends, the invention comprises a frame (1, 2) and a first body (3) that emits negative ions, which comprises a first anodized aluminium plate (7) and a second anodized aluminium plate (8), which are covered with a ceramic paint with silver-doped zeolites, which, in addition to emitting negative ions, constitutes a nanosilver-based biocidal compound. Said aluminium plates (7, 8) are heated uniformly by a wire (6) in order to emit infra-red radiation