A method of removing of recovering an elemental rare earth metal comprises placing a rare earth-containing material comprising a rare earth metal in a reaction solution comprising a reducing agent and a non-aqueous solvent comprising an ionic liquid or a eutectic mixture, reducing the rare earth metal with the reducing agent to form a metallic rare earth metal and cations of the reducing agent, transferring the cations of the reducing agent from the reaction solution to an electrochemical cell through an ion exchange membrane, and reducing the cations of the reducing agent in the electrochemical cell. Related methods of forming an elemental rare earth metal, and related systems are disclosed.

A method of removing of recovering an elemental rare earth metal comprises placing a rare earth-containing material comprising a rare earth metal in a reaction solution comprising a reducing agent and a non-aqueous solvent comprising an ionic liquid or a eutectic mixture, reducing the rare earth metal with the reducing agent to form a metallic rare earth metal and cations of the reducing agent, transferring the cations of the reducing agent from the reaction solution to an electrochemical cell through an ion exchange membrane, and reducing the cations of the reducing agent in the electrochemical cell. Related methods of forming an elemental rare earth metal, and related systems are disclosed.

A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.

A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.

An electrochemical process comprises a step E.sup.l of electrolysis of an electrolyte in order to produce gaseous oxygen and a step of converting oxidation-reduction chemical energy into electrical energy with production of H.sub.2. The electrolyte comprises M.sup.m+ ions of a metal M corresponding to the redox pair (M.sup.m+/M), and A.sup.a+ ions of a depolarization additive A corresponding to a redox pair (A.sup.a+/A). Current is supplied between the anode and the cathode, A.sup.a+ and M.sup.m+ are deposited on the cathode respectively in the form of A and M during the electrolysis and gaseous oxygen is released at the anode. The supply of current between the anode and the cathode is then cut off. Depolarization occurs corresponding to the conversion step C°, with production of H.sub.2 and dissolution of M and A into M.sup.m+ and A.sup.a+ at the electrode acting as the cathode during step E.sup.l and the produced H.sub.2 is collected.

A method for extracting metal ions from water is provided that includes disposing two electrically conductive electrodes in water, where the water includes a target ion species in solution, where at least one of the electrically conductive electrodes is a functionalized electrode having species-specific adsorption of the target ion species, and providing electrical current to the electrically conductive electrodes such that the one or more target ion species are deposited to metallic form or metal oxides at the functionalized electrode by one or more electrochemical reactions.

A method for extracting metal ions from water is provided that includes disposing two electrically conductive electrodes in water, where the water includes a target ion species in solution, where at least one of the electrically conductive electrodes is a functionalized electrode having species-specific adsorption of the target ion species, and providing electrical current to the electrically conductive electrodes such that the one or more target ion species are deposited to metallic form or metal oxides at the functionalized electrode by one or more electrochemical reactions.

A porous transparent electrode is formed where a film comprising of semiconducting nanoparticles is decorated with polyoxometalates (POMs) bonded to their surfaces. The semiconducting nanoparticles are transparent metal oxide. The semiconducting nanoparticles include tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), or titanium dioxide (TiO.sub.2). In an embodiment, the POM is [SiW.sub.12O.sub.40].sup.4−; [α-P.sub.2W.sub.18O.sub.62].sup.6−; or [α.sub.2-P.sub.2W.sub.17O.sub.61].sup.10−. The semiconducting nanoparticles bond to the POM through a combination of electrostatic interactions and hydrogen bonds. The porous transparent electrode can be placed in a protonated form or ion-paired with alkali metal cations or tetraalkylammonium cations.

A porous transparent electrode is formed where a film comprising of semiconducting nanoparticles is decorated with polyoxometalates (POMs) bonded to their surfaces. The semiconducting nanoparticles are transparent metal oxide. The semiconducting nanoparticles include tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), or titanium dioxide (TiO.sub.2). In an embodiment, the POM is [SiW.sub.12O.sub.40].sup.4−; [α-P.sub.2W.sub.18O.sub.62].sup.6−; or [α.sub.2-P.sub.2W.sub.17O.sub.61].sup.10−. The semiconducting nanoparticles bond to the POM through a combination of electrostatic interactions and hydrogen bonds. The porous transparent electrode can be placed in a protonated form or ion-paired with alkali metal cations or tetraalkylammonium cations.

An electrochemical process implements, in a decoupled manner, a first step of electrolysis of an electrolyte to produce gaseous oxygen in a chamber and a second step of electrochemical conversion of H+ ions into gaseous hydrogen in a chamber which contains a liquid phase and a gas phase not dissolved in the liquid phase. Gaseous hydrogen produced in the conversion step is partly present in the gaseous headspace of chamber and as bubbles in the electrolyte, and partly dissolved in the electrolyte which is saturated with hydrogen. The electrolyte has at least one redox pair (A/B) forming at least one intermediate vector enabling the decoupling of the first and second steps. The interface between the gas and liquid phases is increased during the second step to accelerate the diffusion, from liquid phase to gas phase, of the dissolved hydrogen able to supersaturate the electrolyte. Pressurized gaseous hydrogen is then collected.