Abstract: An electrolytic process and apparatus is disclosed for oxidizing or reducing inorganic and organic species, especially in dilute aqueous solutions, and for water purification and treatment. The electrolytic reactor includes an anode, cathode and a packed bed of particulate ion exchange material which, preferably, is modified by converting a portion of the transfer sites to semiconductor junctions which act as mini anodes, or cathodes, to significantly increase the capacity of the reactor to oxidize or reduce the species to be treated, or split water. The ion exchange material may be a monobed of either modified anion exchange material or modified cation exchange material, or a mixed bed of both, and can be in direct contact with either the anode or cathode, or separated from both. Under the influence of direct current, free radical hydroxyl, free radical hydrogen, regenerant hydroxyl ion and/or regenerant hydrogen ion are generated.