Electrochemical systems and methods for removing and recovering phosphorus, in the form of phosphates, from aqueous solutions are provided. The removal of the phosphates takes place in an electrochemical cell having an electrode that includes bismuth (Bi), zinc (Zn), copper (Cu), iron (Fe), or an oxide thereof. During the removal of phosphates from aqueous solution, the metal (Bi, Zn, Cu, or Fe) and/or metal oxide of the electrode is converted into its corresponding metal phosphate within the electrode via a reversible conversion reaction. The phosphate stored in the electrode during the removal step is subsequently released into a recovery solution via electrochemical reduction of the metal phosphate back into a metal.

Disclosed herein are methods and systems that relate to electrochemically oxidizing metal halide with a metal ion in a lower oxidation state to a higher oxidation state; halogenating an unsaturated hydrocarbon or a saturated hydrocarbon with the metal halide with the metal ion in the higher oxidation state; and oxyhalogenating the metal halide with the metal ion from a lower oxidation state to a higher oxidation state in presence of an oxidant. In some embodiments, the oxyhalogenation is in series with the electrochemical oxidation, the electrochemical oxidation is in series with the oxyhalogenation, the oxyhalogenation is parallel to the electrochemical oxidation, and/or the oxyhalogenation is simultaneous with the halogenation.

A hydrogen production system according to the present invention can reduce the power consumed for hydrogen production, has no consumption of cell potential, and can produce hydrogen even by spontaneous reaction to show high hydrogen production efficiency. Furthermore, a composite electrode separator according to the present invention is configured such that an electrode part, a gas-liquid diffusion layer, and a separation plate as a plurality of parts are integrated into one element while the hydrogen production system is included in the electrode part, so that the application of the composite electrode separator to a stack can reduce the number of parts applied to the stack to simplify stack assembling and reduce the stack volume and can increase the operation current density due to a reduction in electrolyte resistance, thereby enabling high-efficiency and high-current driving. Furthermore, a composite hydrogen production stack according to the present invention can not only produce hydrogen gas and electric power together or produce only electric power by adjusting the amount of oxygen, but also produce only hydrogen gas through ammonia water electrolysis. Furthermore, an ammonia fuel cell according to the present invention, by using ammonia as fuel, is an eco-friendly energy source and relatively easy to supply as fuel, has a narrower explosion range than hydrogen, can be liquefied at a low pressure to be easy to store and transport, facilitates leakage detection due to the distinctive smell of ammonia, and can attain wastewater disposal and electricity production simultaneously when ammonia wastewater is utilized.

Apparatuses for the generation of carbon dioxide and hydrogen from a water having a carbonate species are disclosed. The apparatus includes an anodic compartment having an anode disposed on a first side of the anodic compartment and a cathodic compartment having a cathode disposed on a first side of the cathodic compartment. The apparatus further includes a first cation permeable fluidic separator disposed on a second side of the anodic compartment and a second cation permeable fluidic separator disposed on a second side of the cationic compartment. A center compartment is defined between the first cation permeable fluidic separator and the second cation permeable fluidic separator. The apparatus further includes a flow control system configured to independently control flow of water through each of the anodic compartment, the cathodic compartment, and the center compartment. Methods of generating hydrogen, carbon dioxide, and oxygen from seawater using the apparatus are also disclosed.

A method for producing a hydrocarbon including: preparing a molten salt containing a carbonate of a first metal; obtaining precipitates containing a first metal carbide by applying a voltage to the molten salt; and obtaining a gas containing the hydrocarbon and a hydroxide of the first metal by hydrolyzing the first metal carbide.

A method for producing a hydrocarbon including: preparing a molten salt containing a carbonate of a first metal; obtaining precipitates containing a first metal carbide by applying a voltage to the molten salt; and obtaining a gas containing the hydrocarbon and a hydroxide of the first metal by hydrolyzing the first metal carbide.

A method of removing impurities using an electrochemical membrane apparatus comprising introducing a leaching solution into an electrochemical membrane reactor. The leaching solution of the electrochemical apparatus comprises copper, aluminum, iron, cobalt, manganese, and nickel. The electrochemical membrane reactor comprises at least one positive electrode and at least one negative electrode, and the leaching solution is in contact with the at least one negative electrode. A current is applied through the electrochemical membrane reactor to adjust a pH of the leaching solution and copper is deposited on the at least one negative electrode. The aluminum and the iron are removed from the leaching solution, and the cobalt, the manganese, and the nickel are recovered from the leaching solution. An electrochemical membrane apparatus including an electrochemical membrane reactor is also disclosed.

Power is provided to an electrochemical cell. The electrochemical cell includes an anode side and a cathode side. A solution is flowed to the anode side. The solution includes hydrogen sulfide dissolved in water. Water is flowed to the cathode side. The water flowed to the cathode side can be in the form of steam. Providing power to the electrochemical cell facilitates production of sulfur dioxide on the anode side. Providing power to the electrochemical cell facilitates production of hydrogen on the cathode side. A membrane separating the anode side from the cathode side prevents flow of hydrogen sulfide, water, and sulfur dioxide from passing through the membrane while allowing hydrogen cations and oxygen anions to pass through the membrane. Sulfur dioxide is flowed out of the anode side. Hydrogen is flowed out of the cathode side.

An energy utilization system includes a circulation circuit. The circulation circuit includes a pump, a heating section, an electrolytic reduction apparatus, and a thermal energy recovery section. The pump receives a heating medium and outputs the heating medium. The heating section heats the heating medium by using renewable energy or energy obtained from waste heat. The electrolytic reduction apparatus heats an electrolytic solution with heat from the heating medium. The circulation circuit circulates the heating medium. A method for producing a carbon-containing material includes heating a heating medium circulating in a circulation circuit by using renewable energy or energy obtained from waste heat, and performing electrolytic reduction by heating an electrolytic solution with heat from the heating medium that has been heated.

Power is provided to an electrochemical cell. The electrochemical cell includes an anode side and a cathode side. Hydrogen sulfide in a liquid state is flowed to the anode side. An operating temperature and an operating pressure are maintained within the anode side, such that the hydrogen sulfide in the anode side is at a supercritical state. Providing power to the electrochemical cell facilitates electrolysis of the hydrogen sulfide to produce sulfur and protons on the anode side. Providing power to the electrochemical cell facilitates reduction of protons to produce hydrogen on the cathode side. A membrane separating the anode side from the cathode side prevents flow of hydrogen sulfide and sulfur from passing through the membrane while allowing hydrogen cations to pass through the membrane. Sulfur is flowed out of the anode side. Hydrogen is flowed out of the cathode side.