Any metal having a low ?-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an ?-ray after heating the metal at 100? C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an ?-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

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.

Methods of regenerating a metal fuel in a regenerative electrochemical energy storage device are provided. The method includes: (a) providing an anode comprising oxidizable metal fuel; (b) regenerating dendritic metal fuel from the oxidized metal fuel, comprising enhancing dendrite formation of the metal fuel with an additive; and (c) storing the regenerated dendritic metal fuel, comprising suppressing corrosion of the regenerated particulate metal fuel with the additive. The regenerative electrochemical energy storage device may be regenerative metal-air fuel system or a rechargeable alkaline-metal battery. The metal fuel may be dendritic zinc.

An electrochemical reactor adapted to produce hydrogen on demand, including: a device for storing and supplying hydrogen, which includes: a solid-phase metal M layer, and an aqueous liquid electrolyte adapted to oxidise the layer of a metal solid-phase M; a main chamber; a control device, adapted to ensure a relative movement between the electrolyte and the metal M layer so as to be able to present the following two configurations: a withdrawal configuration wherein there is a separation between the electrolyte and the metal M layer; and a contact configuration in which there is contact between the electrolyte and the metal M layer in the main chamber.

This invention presents an electrochemical metallurgical technique for extracting metals and sulfur from metal sulfides, offering an adjustable composition and mechanical properties during electrode preparation. The metal sulfide anode, submerged in an electrolyte with a cathode made of materials like titanium, copper, stainless steel, lead, zinc, aluminum or graphite, undergoes electrolysis. This process oxidizes sulfur in the metal sulfide to the anode and releases metal ions into the electrolyte, where they're reduced at the cathode. The method yields metal at the cathode and sulfur at the anode, with minimal environmental impact, low investment, and straightforward process.

This invention presents an electrochemical metallurgical technique for extracting metals and sulfur from metal sulfides, offering an adjustable composition and mechanical properties during electrode preparation. The metal sulfide anode, submerged in an electrolyte with a cathode made of materials like titanium, copper, stainless steel, lead, zinc, aluminum or graphite, undergoes electrolysis. This process oxidizes sulfur in the metal sulfide to the anode and releases metal ions into the electrolyte, where they're reduced at the cathode. The method yields metal at the cathode and sulfur at the anode, with minimal environmental impact, low investment, and straightforward process.

Catalysts prepared from abundant, cost effective metals, such as cobalt, nickel, chromium, manganese, iron, and copper, and containing one or more neutrally charged ligands (e.g., monodentate, bidentate, and/or polydentate ligands) and methods of making and using thereof are described herein. Exemplary ligands include, but are not limited to, phosphine ligands, nitrogen-based ligands, sulfur-based ligands, and/or arsenic-based ligands. In some embodiments, the catalyst is a cobalt-based catalyst or a nickel-based catalyst. The catalysts described herein are stable and active at neutral pH and in a wide range of buffers that are both weak and strong proton acceptors. While its activity is slightly lower than state of the art cobalt-based water oxidation catalysts under some conditions, it is capable of sustaining electrolysis at high applied potentials without a significant degradation in catalytic current. This enhanced robustness gives it an advantage in industrial and large-scale water electrolysis schemes.

Catalysts prepared from abundant, cost effective metals, such as cobalt, nickel, chromium, manganese, iron, and copper, and containing one or more neutrally charged ligands (e.g., monodentate, bidentate, and/or polydentate ligands) and methods of making and using thereof are described herein. Exemplary ligands include, but are not limited to, phosphine ligands, nitrogen-based ligands, sulfur-based ligands, and/or arsenic-based ligands. In some embodiments, the catalyst is a cobalt-based catalyst or a nickel-based catalyst. The catalysts described herein are stable and active at neutral pH and in a wide range of buffers that are both weak and strong proton acceptors. While its activity is slightly lower than state of the art cobalt-based water oxidation catalysts under some conditions, it is capable of sustaining electrolysis at high applied potentials without a significant degradation in catalytic current. This enhanced robustness gives it an advantage in industrial and large-scale water electrolysis schemes.

A holistic system for sustained capture, confinement and depuration of acid mist generated in nonferrous metal electrodeposition processes utilizing lead anodes, for precluding zero release of gaseous fluid pollutants in the atmospheric air surrounding electrodeposition processes, providing an assured solution to acid mist control and total abatement in an effective, efficient manner and sustainable in time by immediate recovery and recycling back in the source generating the contaminant effluents as there are produced, according to a cell by cell strategy, and directly connecting each cell to a system for depuration, recovery and recycling the contaminants gaseous fluid flow extracted from each cell reducing them to innocuous levels in the discharge to the open atmosphere; complying the condition of 100% Null escape of acid mist from each individual cell to the working environment, simultaneously with minimum power usage, and substantial global gaseous fluid contaminant reduction, far exceeding present minimum sustainability standards, in terms of human health, energy usage and environmental protection.