Abstract: The invention concerns a method consisting: in passing the sea water through an electrically conductive catalyst (10), arranged in the cathode section of an electrolytic cell (1), comprising a cathode section (3) and an anode section (4) provided with, the former, with at least one cathode (11a, . . . ) and, the latter, with at least one anode (18) and separated by a wall (2) permeable only to the cations and in circulating, in the anode section (4), a conductive aqueous solution of a particular anolyte; in providing an electric voltage between the cathode and the anode of the cell (1) while maintaining the contents of the cathode and the anode sections at specific potentials, so as to produce, in the cathode section, consumption of oxygen dissolved in the treated water and in decomposing, in the anode section, an appropriate amount of solution for ensuring the electroneutrality of the treated water.

Abstract: Cerous 3.sup.30 values are converted into ceric 4.sup.+ values, in a conventional separator-free electrolytic cell, by emulsifying an organic phase containing a cerium 4.sup.+ extractant in an aqueous sulfuric phase which includes the cerium 3.sup.+ values to be converted; simultaneously electrolytically oxidizing the cerium 3.sup.+ values into cerium 4.sup.+ values in a zone of electrolysis including an anode and a cathode, whereby the cerium 4.sup.+ values formed are liquid/liquid extracted into the organic phase; separating the resulting emulsion into an aqueous phase and an organic phase enriched in cerium 4.sup.+ values; and recovering the enriched organic phase.