A system (1) for generating hydrogen gas comprises a reaction vessel (101) containing an aqueous solution (102) and a cathode (105) and an anode (107) each positioned at least partly in the reaction vessel (101). The system (1) comprises first and second ultrasonic transducers (215-220) which emit ultrasonic waves in the direction of the cathode (105) and the anode (107) respectively. Each ultrasonic transducer (215-220) is driven by a respective transducer driver (202) to optimise the operation of the system (1) for generating hydrogen gas by sonoelectrolysis.

An optimised bio-electrochemical reactor for treating a liquid effluent containing a biodegradable organic pollution. At least one of the anode and cathode compartments of the reactor is a microbial biofilm compartment (12) including a multi-stage current collector immersed in an electrolyte comprising electroactive microorganisms. This current collector includes at least two stages, each defining a chamber acting as a container for a biocompatible granular support material and letting the fluid pass through. The effluent circulates inside the compartment (12) according to an X direction crossing the stages of the current collector. In operation, the support material (17) is in a fluidised state resulting either from the circulation of the effluent, or from the circulation of a fluidisation gas allowing optimising the active surface of the electrode and, consequently, the treatment of the effluent.

An optimised bio-electrochemical reactor for treating a liquid effluent containing a biodegradable organic pollution. At least one of the anode and cathode compartments of the reactor is a microbial biofilm compartment (12) including a multi-stage current collector immersed in an electrolyte comprising electroactive microorganisms. This current collector includes at least two stages, each defining a chamber acting as a container for a biocompatible granular support material and letting the fluid pass through. The effluent circulates inside the compartment (12) according to an X direction crossing the stages of the current collector. In operation, the support material (17) is in a fluidised state resulting either from the circulation of the effluent, or from the circulation of a fluidisation gas allowing optimising the active surface of the electrode and, consequently, the treatment of the effluent.

A method for electrolysis of water using a device having a reversible cell for the production of hydrogen and oxygen is disclosed. The method includes preparing an aqueous alkaline solution of KOH having a concentration of potassium hydroxide (KOH) of between 35% and 55% w/v in a mixer; heating the aqueous alkaline solution to between 150 C. and 374 C.; increasing the pressure to maintain the aqueous alkaline solution in the liquid phase at a minimum pressure condition of between 2.2 bar and 129.1 bar; passing the water through the hydrophobic layer of each electrode and reaching the catalyst layer to catalyse a reduction phase of the hydrogen or an oxidation phase of the oxygen and the porous electrode layer to carry out the reduction and oxidation; and collecting the released gaseous hydrogen and oxygen.

The embodiments of the present disclosure relate to a method and apparatus for producing a CNM product that may comprise carbon nanotubes (CNTs). The method and apparatus employ carbon dioxide (CO.sub.2) and a carbonate electrolyte that is lithium-free as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, a graphene-defect agent may be introduced into the electrolysis reaction.

The embodiments of the present disclosure relate to a method and apparatus for producing a CNM product that may comprise carbon nanotubes (CNTs). The method and apparatus employ carbon dioxide (CO.sub.2) and a carbonate electrolyte that is lithium-free as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, a graphene-defect agent may be introduced into the electrolysis reaction.

A membraneless electrolysis cell, which includes a solid body, the solid body having a central cavity, two housings, at least one secondary cavity, at least one duct for providing a material, two ducts for admitting two electrolyte flows, and at least one supply duct. The cell configuration allows a material, in particular a reagent, to be fed selectively to the anode or cathode, separate from the electrolyte flow.

Disclosed is a purification method of electrolytic gas generated from an electrolysis cell having a cathode and an anode. In a step of performing electrolysis of an electrolyte solution supplied into the electrolysis cell and repeating the electrolysis while circulating the electrolyzed electrolyte solution via an circulation tank disposed outside the electrolysis cell, a bag-shaped membrane pack, which is made from a specific porous membrane material, is of a shape having an opening at a top end thereof and closed at an entire side wall and entire bottom wall thereof and has a large permeation area at the entire side wall and entire bottom wall, is disposed in an interior of the circulation tank, thereby enabling to perform the electrolysis while purifying the electrolyte solution in which a portion of the electrolytic gas generated by the electrolysis is dissolved and bubbles of another portion of the electrolytic gas coexist.

The present disclosure concerns a process and a system for the electrochemical reduction of oxalic acid to glyoxylic acid. The process involves withdrawing a portion of oxalic acid-depleted catholyte from the process and contacting it with a quantity of solid oxalic acid to provide a concentrated oxalic acid solution which is re-entered into the process.

The present disclosure concerns a process and a system for the electrochemical reduction of oxalic acid to glyoxylic acid. The process involves withdrawing a portion of oxalic acid-depleted catholyte from the process and contacting it with a quantity of solid oxalic acid to provide a concentrated oxalic acid solution which is re-entered into the process.