A process for the removal of heavy metals, particularly arsenic, from water comprises filling an electrolytic cell 1 with water which is to be treated, wherein the electrolytic cell is equipped with a plurality of electrodes 2 subdivided into anodes and cathodes. The anodes are dissolved under the action of an electric current flowing from the anodes to the cathodes. Oxygen, or a gas containing oxygen, is injected into the space between every anode and cathode couple. Suitably, the anodes and cathodes are made of iron or iron alloy. Therefore, ferrous hydroxide can be generated at the anode, which may then be oxidised by oxygen dissolved in the water to form ferric hydroxide. The ferric hydroxide may then adsorb arsenic. The electrodes can be in the form of vertical parallel plates or inclined parallel plates. Alternatively, the electrodes may be made of expanded mesh and placed horizontally. Preferably, the gas containing oxygen is air. The electrolytic cell can operate in batch mode or continuous flow mode, in both cases the cell is equipped with an inlet 3 and an outlet 4.