Abstract: A process for increasing the active surface area of at least one electrode having a surface comprising a group VIII metal in an electrochemical cell, which also comprises at least one balancing electrode and an aqueous electrolyte which comprises nitrate ions, which comprises applying a sweeping voltage across the electrodes at a rate of at least 0.2 V/s, the sweeping voltage being from a lower voltage which is between the voltage at which hydrogen evolution occurs and ?0.7 V to an upper voltage which is between ?0.2 V and +0.3 V, all of the above voltages being with reference to a standard calomel reference electrode (VSCE).

Abstract: A process for removing nitrate ions from an aqueous solution thereof which comprises passing the solution through an electrochemical cell comprising at least one anode and at least one cathode and passing a current therebetween, wherein the cathode surface (s) comprise rhodium metal.