TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Electrode: In the electrode, the graphenes, mixture of graphenes and other nanostructured carbon-based materials, or mixture of graphenes and other non-nanostructured carbon-based materials, are compressed to form a compact structure. The mixture of graphenes and other nanostructured carbon-based materials are compressed with pressure higher then 300 kg/cm2. Preferred Components: The graphemes (60-90 wt.%) comprise the graphene-derivatives graphene-oxides and graphanes. The nanostructured carbon-based materials are fullerenes, carbon nanotubes, graphite nanoplates, carbon nanofibers or their mixtures. The non-nanostructured carbon-based materials are expanded graphite or other graphite-based compounds. The anode comprises a mixture of graphene and other carbon-based nanostructured material having graphene (60-90 wt.%). Preferred Process: The process further involves the treatment of the liquid waste by means of photocatalytic oxidation of at least one of the contaminants in the presence of photocatalyst material consisting of a combination of rutile and/or anatase and graphenes in contact with each other. In the process, the electric current has an intensity of 10-70 mA/cm2 of electrode. The voltage difference of 2-15 Volts is applied between the anode and the cathode. The salt is added to the liquid waste to adjust the conductivity of the liquid. The pH of the liquid to be treated is adjusted by adding an acid or a basic compound. In the process, when the liquid contains relevant amounts of oxidable substances, the addition makes the liquid pH acid; and when the liquid contains hydrocarbons, the addition makes the liquid pH basic. The magnetic field is applied to the liquid to be treated. The photocatalytic oxidation treatment occurs at the same time as the electrooxidation process. The photocatalytic oxidation treatment takes place downstream of the electrooxidation process.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The salt is sodium chloride or sodium sulfate. EXAMPLE - No suitable example is given.