Abstract: A process and electrodialytic cell for electrodialytically regenerating an aqueous, spent electroless copper plating bath which contains alkali metal salts as reaction products of the electroless plating process. In the process, the spent copper plating bath is introduced into a regeneration compartment of an electrodialytic cell. Anions of the alkali metal salts in the spent copper plating bath are electrodialytically transferred through an anionic membrane into an acid formation compartment. Hydroxyl ions are electrodialytically transferred through the anionic portion of a bipolar membrane to a regeneration compartment to regenerate the bath. The electrodialytic cell of the invention has means for establishing and maintaining in a plurality of regeneration compartments the spent electroless copper plating bath.

Abstract: The method and apparatus for rinsing an electrodialysis electrode provides isolation from the fluid being electrodialyzed. The method utilizes the natural circulation of the liquid and provides an exchange between the anode and cathode liquids while maintaining electrical isolation to thereby improve the efficiency of the electrodialysis cell and reducing the power requirements. The method of rinsing makes use of the gas generated at the electrodes to provide a motivating fluid for circulating the electrode rinse liquid. Circulation of the fluid is carried out in the slug flow region to provide electrical isolation. In the multi chamber apparatus the chamber adjacent to both of the electrode chambers contains the dilute liquid and is positioned between the electrode chamber and the chamber containing the concentrated solution to prevent migration of ions from the concentrated solution into the electrode chamber to contaminate the electrode.

Abstract: A process is provided for regenerating a spent electroless copper plating bath which contains alkali metal salts resulting from the reduction of a water soluble copper salt under copper plating and reducing conditions. The regeneration is effected by means of the electrodialytic transfer of at least a portion of the anions in the spent plating bath through an anionic permselective membrane into the anode compartment of an electrodialytic cell. In the preferred embodiment, hydroxyl ions from the cathode compartment of the electrodialytic cell are concurrently transferred through a second anionic permselective membrane to replace the transferred anions, the replacement taking place in a compartment of the electrodialytic cell located between the two anionic permselective membranes.