Planar carbon fiber and noble metal oxide electrodes and methods of making the same

Planar electrodes include a carbon fiber cloth which is woven or braided from a plurality of PAN-derived carbon fibers and which is mounted in a frame. The frame is preferably made of an inert plastic material such as TEFLON, PVC, or DELRIN and the carbon fiber cloth is preferably affixed to the frame with metal strips and fasteners. The metal strips are preferably titanium or a noble metal and the fasteners are preferably made of the same metal as the strips. The metal strips form a low impedance electrical contact with the carbon fiber cloth and enable the electrode to be coupled to a wire lead or electrical contact for use in an electrochemical circuit. According to a second embodiment, the carbon fiber cloth is sandwiched between two metal frames. According to a third embodiment, the carbon fiber cloth is sandwiched between two plastic frames with conductive foil strips or titanium strips forming an electrical contact with the carbon fiber cloth. The carbon fiber cloth may be coated with a noble metal oxide either before or after attachment to the frame. The electrodes according to the invention are ideally suited for use in a nitrate removal system as cathodes and anodes. When used as anodes, several layers of carbon fiber cloth are mounted in a frame. A nitrate removal system incorporating electrodes according to the invention is also disclosed.