Abstract: Apparatus for regenerating activated carbon comprises a desorption tank having at its bottom an elongate channel-form passage sloping downwardly from an inlet end to an outlet end. A pulse voltage is applied to electrodes extending along the passage to regenerate the activated carbon as it flows from the inlet to the outlet. Flow of the activated carbon is intercepted by transverse weirs provided at spaced intervals along the length of the passage. An oscillatory swinging motion imparted to the tank by eccentrics on a rotating shaft promotes flow of the activated carbon along the passage from the inlet to the outlet and in particular causes carbon particles which have become lighter by virtue of regeneration to pass preferentially over the weirs and thereby progress more rapidly toward the outlet.