Abstract: A system for chemical compounds collection, deposition and separation in a fluid stream includes: a stack of layers with a number of window openings, allowing the fluid stream to pass through, neighboring layers forming an angle 0??<90°, the angle and the distance between neighboring layers being variable and controlled, so as to control the velocity of the fluid stream; spreading apertures in between the layers, and adapted to spray liquid chemical solution inside the closed volume, so as to create a thin film on the surfaces of the layers and lateral walls of the closed volume; a system for generating droplets of chemical solution upstream of the stack, to be mixed in the fluid stream; particles of the chemical compounds being collected by impaction with the droplets, and by diffusion on the thin film, and counter flowing with the chemical solution.