Abstract: Process for production of hydrogen of high purity by photoelectrochemical means with low energy consumption. The process is carried out in an electrochemical cell which comprises at least one anodic chamber with an anode and at least one cathodic chamber with a cathode, in which the two chambers are separated by an ion-exchange membrane, where: i) the anodic chamber contains an aqueous anodic solution which comprises the Fe2+ion, and the aqueous solution is adjusted to a pH less than or equal to 5; ii) a sacrificial substance is added to the anodic chamber; iii) the anodic solution is irradiated with ultraviolet light and/or visible light; iv) the cathodic chamber contains an aqueous cathodic solution which has a proton concentration equal to or higher than 10?3 M; and v) electric current is fed between the anodic chamber and the cathodic chamber separated by the membrane, this membrane being a proton-selective ion-exchange membrane impermeable to the iron and impermeable to the sacrificial substance.

Abstract: The invention refers to a selective metal leaching process from the materials that contain them, in which said metals come into contact with a solution comprising said process two or more in this order, of the following leaching steps: (a), (b) or (c) in the following order: (a) Treatment of the material with an aqueous solution in the presence of oxygen; (b) Treatment of the remaining material with an aqueous solution in the presence of oxygen and ozone; (c) Treatment of the remaining material with an aqueous solution in the presence of oxygen, ozone and a third reagent. And optionally a step of separation of phases is carried out after every one of the previously steps (a), (b) or (c). Said process is used for the recovery of metals from scrap, ores, concentrates and mixtures of these.

Abstract: Irradiation can be carried out with direct or indirect sunlight. Ozonisation and irradiation can be carried out simultaneously or the irradiation can be carried out after ozonisation. The ozonisation can be carried out in the presence of a catalyst in homogeneous phase.

Abstract: The process comprises the oxidation, in an electrolytic cell provided with at least one anodes of pollutants which contaminate wastewaters, and is characterized in that oxygen is diffused in the electrolytic cell cathode or cathodes subjected to a voltage lower than 100 V in order to reduce said gas to a dissolution oxidizing species selected among hydrogen peroxide or hydroxyl and/or peroxydril (HO2·) radicals. The equipment for implementing said process comprises an elecrolytic cell continuously supplied and provided with an anode (1) and two oxygen diffusion cathodes (2) and is sealed on either side with a frame (3), said frames and cathodes delimiting the compartments (4) which are supplied with oxygen gas and/or gas mixtures containing oxygen through inlets (6); similarly, the cathode and the anode delimit the compartments (5) through which circulates the contaminated water entering through the inlet (5) and coming out through outlets (8).

Abstract: Process for the reduction of halogenated hydrocarbons and for obtaining their derivatives in an electrolytic cell which includes at least one cathode, at least one anode and a solution. A hydrogen-permeable membrane is arranged in the at least one anode such that the at least one anode constitutes a hydrogen-diffusion anode, and hydrogen or a hydrogen-containing gas is supplied to the hydrogen-permeable membrane. An electrolytic cell for the reduction of halogenated hydrocarbons includes at least one high overpotential cathode containing lead, cadmium, graphite, copper and/or tin, at least one hydrogen-diffusion anode containing palladium and a solution.