Patents

The invention provides an electrochemical coagulation process for the removal of nitrate from drinking water, wherein the nitrate is removed by adsorption of metal hydroxide, formed by in-situ anodic oxidation. The electrochemical coagulation process of the invention, for the removal of nitrate from drinking water, obviates the drawbacks of the commonly used treatments processes such as electrochemical method and membrane techniques. The electrochemical coagulation process consists of an electrochemical flow cell fitted with an anode and cathode of aluminum alloy with an inter-electrode distance of 0.1 to 0.2cm. Drinking water containing 250 to 800 mg/l of nitrate at a pH in the range of 2-13 and at a temperature between 20-80oC is electrolyzed at anode and cathode current densities between 0.1 - 0.5 A. dm-2. The aluminum hydroxide formed from the anode during electrolysis adsorbs the nitrate present in the water and removed by filtration. The removal efficiency of this method is up to 99%.