WO2021260020A1

WO2021260020A1 - Electrolyzing vane device for the electrochemical treatment of effluents

Info

Publication number: WO2021260020A1
Application number: PCT/EP2021/067176
Authority: WO
Inventors: Emmanuel Mousset
Original assignee: Centre National De La Recherche Scientifique
Priority date: 2020-06-26
Filing date: 2021-06-23
Publication date: 2021-12-30
Also published as: FR3111887A1; EP4182273A1; FR3111887B1

Abstract

Disclosed is an electrochemical device for the electrochemical treatment of effluents comprising at least one electrolyzing vane, wherein the at least one electrolyzing vane comprises two electrodes separated by a spacer having a thickness of between 1 and 1000 µm, preferably between 20 and 800 µm, more preferably between 50 and 500 µm, wherein the at least one electrolyzing vane is movably mounted on a supporting unit.

Description

DESCRIPTION

TITLE: Electro-blade device for the electrochemical treatment of effluents.

Technical area

The present invention relates to the field of the electrochemical treatment of liquid effluents or of sludge. The present invention relates, in particular, but not exclusively, to advanced oxidation electrochemical treatment (PEOA) processes.

State of the prior art

Processes for the electrochemical treatment of water are known in the state of the prior art. In particular, advanced oxidation electrochemical treatment processes (PEOA) are known.

In the state of the prior art, for the purposes of implementing PEOAs, the use of electrochemical cells of the filter press type is known.

Also known in the state of the prior art, the use of standard electrochemical cells which are placed in perfectly stirred reactors during the implementation of PEOA.

One aim of the invention is in particular:

- eliminate organic and / or inorganic pollution and / or disinfect a liquid or viscous fluid, and / or

- to consume less electrical energy during the electrochemical treatment of effluents, and / or

- not to consume electrical energy during the electrochemical treatment of effluents, and / or

- to propose a device and a method which allow better efficiency during the electrochemical treatment of effluents, that is to say a better effluent elimination rate and / or a better effluent reduction rate and / or reduced processing time, and / or

- not to add reagents or additives during the electrochemical treatment of effluents, and / or

- to implement the electrochemical treatment in effluents having a conductivity of less than 5 mS / cm without adding electrolyte support, and / or

- limit the discharge of toxic and / or polluting by-products, and / or

- recovering inorganic species present in the fluid to be treated, for example rare and / or heavy metals.

Presentation of the invention

To this end, an electrochemical device is proposed for the electrochemical treatment of effluents comprising at least one electro-blade, the at least one electro-blade comprising, preferably consisting of, two electrodes separated by a spacer having a thickness between 1 and 1000 μm, preferably between 20 and 800 μm, more preferably between 50 and 800 μm, said at least one electro-blade being mounted movably on a support unit.

Preferably, the at least one electro-blade comprises a single pair of electrodes separated by a spacer.

Preferably, the at least one electro-blade comprises less than three electrodes. Preferably, the at least one electro-blade comprises only two electrodes and the spacer.

Preferably, each of the electro-blades among the at least one electro-blade constitutes an electrochemical cell.

The at least one electro-blade can have, in whole or in part, a planar or curved shape. The at least one electro-blade can have a parabolic or ovoid shape.

The at least one electro-blade can be included in a plane. The at least one electro-blade can extend in a plane.

The at least one electro-blade can extend along a curved surface, such as for example a parabola. In this case, the plane along which the electro-blade extends can be defined as a set of planes each defined at any point along an axis, for example a chord of the at least one electro-blade or a line of camber of at least one electro-blade, along which the electro-blade extends, preferably radially.

Preferably, the two electrodes of an electro-blade are an anode and a cathode. In this case, the anode can extend, at least partly, preferably entirely, on a face of the electro-blade which is opposite to a face on which the cathode extends, at least in part, preferably entirely.

Preferably, the thickness of the spacer constitutes the distance between the two electrodes. The thickness of the spacer can vary within the at least one electro-blade and / or from one electro-blade to another.

Preferably, the at least one electro-blade constitutes a solid assembly or a compact assembly or is in one piece. Thus, preferably, the distance, or the distance profile, when the distance varies within the same electro-blade, between the electrodes is constant.

The spacer is arranged to transport ionic charges between the two electrodes. The spacer can be a semi-permeable or semi-permeable membrane.

The spacer is designed not to short-circuit the two electrodes. The spacer can be a fluid, a solid or a gel.

The solid spacer can be porous or non-porous.

The spacer can form an airtight volume between the two electrodes.

The spacer can be a gas or a liquid. The spacer may be a volume intended to receive the effluent to be treated and / or to allow circulation of the effluent to be treated between the two electrodes. The spacer can be a gas, in particular when the electro-blade is not immersed in the effluent and / or can be the effluent, in particular when the electro-blade is immersed in the effluent. Preferably, the spacer may comprise an insulating material or be made of an insulating material.

Preferably, the thickness of the spacer is:

greater than 1 μm, preferably 5 μm, more preferably 10 μm, more preferably 15 μm, more preferably 20 μm, more preferably 25 μm, more preferably 30 μm pm, even more preferably at 40 pm and most preferably at 50 pm, and / or

-lower than 1000 µm, preferably 900 µm, more preferably 800 µm, more preferably 750 µm, preferably 700 µm, preferably Still more than 650 µm, more preferably 600 µm, still more preferably 550 µm and most preferably 500 µm.

The at least one electro-blade can be mobile in one or more directions.

The at least one electro-blade can be mounted to move in translation and / or in rotation.

Preferably, the at least one electro-blade is mounted movably relative to the support unit. The device may have a state, called the working state, in which it is in operation. Preferably, the at least one electro-blade is movably mounted on the support unit in an operating state of the device. Preferably, the at least one electro-blade is movably mounted on the support unit when the device is in working order. In other words, the at least one electrode is preferably mounted movably on the support unit when effluents are being processed. Preferably, the at least one electro-blade is movably mounted on the support unit when the apparatus is not in working order.

Preferably, the mobile arrangement of the electro-blade allows: a setting in motion of a fluid, in which the at least one electro-blade is intended to be immersed, at least in part, by the 'at least one electric blade, and / or

- A setting in motion of at least one electro-blade by the fluid.

In the present application, it can be understood by at least one electro-blade: a single electro-blade, one electro-blade from among several electro-blades, several electro-blades or each electro-blade of the device.

The thickness of the spacer according to the invention allows, among other things:

- to decrease the current densities necessary for the electrochemical treatment, and / or - to decrease the ohmic drop between the two electrodes of the at least one electro-blade, to decrease the potentials applied between the two electrodes, and consequently contributes to avoid the phenomenon of clogging, and / or

- improve the transfer and transport of material between the two electrodes of the at least one electro-blade, and / or - To generate highly reactive species, for example hydrogen peroxide at the cathode, without adding species to the solution to be treated, for example by using the oxygen generated at the anode. The device may include a connecting element to which the at least one electro-blade is fixed, the connecting element is:

- connected, by means of a fixed or mobile link, to the support unit, and

- Arranged to transmit a force from the support unit to the at least one electro-blade or vice versa. The connecting element may comprise a connecting shaft or a fastening element, such as for example an internal thread or a fastening clips. The fixing element may be provided in the at least one electro-blade.

Preferably, the at least one electro-blade extends, at least in part, radially with respect to the connecting element. The link member can be attached to the support unit.

Preferably, the fixed or movable connection connecting the connecting element to the support unit can be rectilinear or annular or of the ball, slide or pivot type or be a sliding connection. The at least one electro-blade forms a non-zero angle with one or more directions in which the at least one electro-blade is movable.

Preferably, the at least one electro-blade is arranged, relative to the at least one connecting element, so as to form a non-zero angle with one or more directions in which the at least one electro-blade is mobile.

When the device comprises at least two electro-blades; several or each of the electro-blades can be mobile:

- at a given instant, in one or more different directions or each in a different direction, or - at any time, in several different directions or each in a different direction.

The at least one electro-blade can be mobile, at a given instant or at any instant, in the same direction.

Preferably, each of the electro-blades among the at least one electro-blade can form a non-zero angle with one or more directions in which or in which the at least one electro-blade is mobile or arranged to be set in motion.

Preferably, at least one surface of the at least one electro-blade forms a non-zero angle with one or more directions in which the at least one electro-blade is movable. More preferably, at least part of a surface of the at least one electro-blade forms a non-zero angle with one or more directions in which the at least one electro-blade is movable.

Preferably, the angle formed between said at least one electro-blade and the direction or directions in which the at least one electro-blade is movable is greater than 10 °, preferably less than 80 °, more preferably between 20 ° and 80 °, more preferably between 30 ° and 50 °.

A tangential flow and / or a radial flow and / or an axial flow of fluid are generated, concomitantly and at any time in an operating state of the device, at at least one surface of the electro-blade by:

the non-zero angle formed between the at least one electro-blade and the direction or directions in which the at least one electro-blade is movable, and

- the mobile nature of the electro-blade. The tangential and / or radial and / or axial flows are defined with respect to the at least one surface of the electro-blade.

A flux comprising a tangential component and a radial component can be generated at the level of at least one surface of the electro-blade.

The synergy between the non-zero angle formed between the at least one electro-blade and the direction (s) in which the at least one electro-blade is mobile and the mobile aspect of the electro-blade makes it possible to optimize the generation of the tangential flow and / or the radial flow and / or the axial flow of fluid generated at at least one surface of the electro-blade and offers better homogeneity and better control of the tangential flow and / or the radial flow and / or the axial flow of fluid generated at at least one surface of the electro-blade.

The synergy between the non-zero angle formed between the at least one electro-blade and the direction (s) in which the at least one electro-blade is mobile and the mobile aspect of the electro-blade has the effect of 'entrain gases (gas bubbles) by the movement of at least one electro-blades, and therefore of the electrodes. The entrainment of gases (gas bubbles) allows: - minimize the clogging of the electrodes and the spacer, and / or

- improve charge transfer and / or faradic reactions and / or highly reactive species generated at the electrodes, and / or

- to increase the transfer of material to the surface of the electrodes.

The at least one electro-blade can be arranged so as not to have a surface extending entirely along a plane forming a non-zero angle with a direction of movement of the electro-blade.

The at least one electro-blade can be arranged to present at least one surface extending along a plane forming a non-zero angle with a direction of movement of the electro-blade.

Preferably, a surface along which the at least one electro-blade mainly extends forms a non-zero angle with the direction (s) in which the at least one electro-blade is movable.

It can be understood by surface of at least one electro-blade:

the surface, preferably the largest surface, of the cathode and / or of the anode along which the electro-blade extends.

Preferably, at least part of a surface of each of the at least one electro-blade forms a non-zero angle with a direction of movement of the electro-blade.

The at least one electro-blade can be arranged, relative to the connecting element, so that a minimum angle formed between a surface or at least a part of the surface or each point of the surface of the au at least one electro-blade and an axis along which the connecting element mainly extends, called the connecting axis, is less than 85 °.

The connecting element may extend along a straight line, a series of straight segments forming a non-zero angle between them and / or a curve. Preferably, the connecting element extends along an axis, called the connecting axis. In this case, the link axis can be considered as the axis extending between a link point, or fixing point, of the link member on the support unit and the point of fixing of the link member. connection on the electro-blade.

It can be understood by "mainly", in particular in the sense "... extend mainly according to ...", the principal component according to which extends the object in question. In other words, the surface or at least part of the surface or each point of the surface of the at least one electro-blade and the connecting axis are not mutually perpendicular.

Preferably, the minimum angle formed between a surface or at least a part of the surface or each point of the surface of the at least one electro-blade and the direction (s) in which the main direction or which extends mainly the connecting element is between 30 and 45 °.

The synergy between the spatial and / or geometric arrangement of the at least one electro-blade and the mobile aspect of the at least one electro-blade allows, among other things:

- an improvement in the transfer and mass transport from the solution to the two electrodes of the at least one electro-blade, and / or

- Better homogenization and better mixing of the fluid in which the at least one electro-blade is intended to be immersed.

The spacer can be arranged to allow the diffusion of the species between the two electrodes of the at least one electro-blade.

The spacer can comprise a porous solid material.

The term “porous material” can be understood to mean a material comprising at least one pore and / or at least one perforation.

Preferably, the spacer is made of a porous solid material.

The spacer can be an ion exchanger. The term “ion exchanger” can be understood to mean a semi-permeable membrane, an ion selective membrane or an ion exchange resin.

Preferably, the spacer is made of a non-conductive material.

The at least one electro-blade can be supplied, electrically, individually.

Each electrode of the at least one electro-blade can be supplied in mono-polar mode or in bipolar mode. Preferably, each electrode of the at least one electro-blade is supplied in mono-polar mode. The at least one electro-blade can extend, at least in part, in a radial direction with respect to the connecting axis.

Preferably, the at least one electro-blade extends mainly radially with respect to the link axis. The at least one electro-blade can extend radially along a straight line or a curve.

By way of example, if the at least one electro-blade has a helical shape, the straight line along which the at least one electro-blade extends radially can be the chord of the at least one electro-blade or the camber line of at least one electro-blade.

Preferably, the at least one electro-blade extends from the axis of the link and mainly in a direction forming a non-zero angle with the said link axis.

Preferably, the at least one electro-blade extends from the link axis in a direction forming a right angle with said link axis.

Preferably, the connecting axis is an axis of rotation of the at least one electro-blade.

The device can comprise a conversion means arranged to convert a movement of the at least one connecting element into electricity intended to supply electrically the at least one electro-blade.

By way of example, the conversion means can comprise a rotor and a stator.

The movement of the at least one connecting element can be generated by a force exerted on the at least one electro-blade by a moving fluid. Preferably, the fluid is in motion relative to the support unit and / or relative to the connecting element and / or relative to the at least one electro-blade. Preferably, the moving fluid is the effluent to be treated. The at least one connecting element can be a transmission shaft designed to be rotated and to transmit a torque from then the support unit to the at least one electro-blade or vice versa.

The transmission shaft can be arranged to be rotated and / or in translation, preferably relative to the support unit and / or relative to or in the fluid. The electro-blade can be mobile, according to a translational and / or rotational movement, preferably relative to the support unit and / or relative to the connecting element and / or relative to or in the fluid . The device may comprise several electro-blades, a material of one or each of the electrodes of an electro-blade being different from a material of one or each of the electrodes of another of the electro-blades.

The device may comprise: - an electric machine capable of operating in motor mode and / or in generator mode, the connecting element being connected to a rotor of the electric machine, and / or

- a generator arranged to supply at least one electro-blade, and / or

- a rotating connector on which the connecting element is mounted. The connecting element can be connected directly or indirectly to the rotor of the electric machine.

One or each of the electrodes of the at least one electro-blade can comprise: - carbon and / or metal oxides such as, for example, lead dioxide, PbÜ2, and / or tin dioxide, SnÜ2, and / or substoichiometric titanium dioxide, (TiOx, x <2, for example T14O7) and / or boron doped diamond (BDD); preferably for the implementation of PEOAs, or

- stainless steel and / or iron and / or aluminum; preferably for the implementation of electrocoagulation methods, or

- BDD and / or mixed metal oxides and / or carbon; preferably for the implementation of electro-oxidation processes, or

- porous conductive materials having a specific surface greater than 0.1 m ² . Preferably, the cathode can comprise, preferably can be made of, a material exhibiting a strong overvoltage in the evolution of hydrogen.

Preferably, the cathode may comprise, preferably may be made of, a carbonaceous material such as, for example, carbon felt, carbon fiber. activated carbon, graphite, or may comprise, preferably may consist of, stainless steel.

Preferably, the anode may comprise, preferably may be made of, a material exhibiting a strong oxygen evolution overvoltage. Preferably, the anode can comprise, preferably can be made of, a carbonaceous material such as, for example, diamond doped with boron and / or PbO2 and / or SnO2 and / or TiOx (x <2) and / or iron and / or aluminum and / or mixed metal oxides.

One or each of the electrodes of the at least one electro-blade can be:

- porous, preferably only one of the electrodes among the two electrodes of the at least one electro-blade is porous, and / or

- Perforated, preferably the other of the electrodes among the two electrodes of the at least one electro-blade is perforated.

Preferably, a perforated electrode comprises through openings, preferably the openings extend along a thickness of the electrode, greater than 500 µm in size.

Preferably, the cathode and / or the anode is a porous and / or perforated material.

According to the invention, there is also proposed a use of the device for the treatment of effluents.

According to the invention, a use of the device is also proposed for carrying out advanced oxidation electrochemical treatment methods (PEOA).

According to the invention, there is also proposed a process for the electrochemical treatment of effluents comprising:

- an application of a potential difference or an injection of a current between two electrodes of at least one electro-blade, the electrodes of the electro-blade being separated by a spacer having a thickness between 1 and lOOOpm, - a setting in motion in a fluid of at least one electro-blade in one or more directions, and / or

- A setting in motion of the fluid in which the at least one electro-blade is immersed. The method can be implemented, subsequently or concomitantly, by means of several electro-blades.

The electro-blade can be at least one electro-blade of the device according to the invention.

Preferably, the fluid in which the electrode is set in motion contains effluents to be treated. More preferably, the effluent to be treated constitutes the fluid in which the electro-blade is set in motion.

The at least one electro-blade can be immersed, at least in part, in the fluid. Preferably, the at least one electro-blade is completely immersed in the fluid. The fluid may be in motion before it is brought into contact with the at least one electro-blade. The method may include contacting a flow of fluid with the at least one electro-blade. In other words, a flow of fluid can be brought into contact with the at least one electro-blade during the implementation of the method.

The method may include a step consisting in forming:

- a non-zero angle between the at least one electro-blade and the direction (s) in which the at least one electro-blade is set in motion, and / or - a non-zero angle between the at least an electro-blade and one or more directions according to which the fluid is in motion.

Preferably, a non-zero angle is formed between a surface of the at least one electro-blade and the direction or directions in which the at least one electro-blade is set in motion and / or the direction or directions. tions according to which the fluid is in motion. More preferably, a non-zero angle is formed between at least part of a surface of the at least one electro-blade and the direction or directions in which the at least one electro-blade is set in motion. and / or the direction or directions in which the fluid is moving. The method may include, when the electric blade is set in motion:

- an application of a force by at least one electro-blade on the fluid, and / or

- an application of a force by the fluid on the at least one electro-blade, and / or

- a setting in motion of the fluid by at least one electro-blade, and / or

- a setting in motion of at least one electro-blade by the fluid, and / or

- generation of a tangential flow and / or a radial flow and / or an axial flow of fluid at the level of at least part of a surface of the electro-blade,

- electrocoagulation and / or electro-flotation and / or electro-sorption and / or electro-oxidation, advanced or not, and / or electro-reduction, advanced or not, and / or electro-precipitation and / or electrodeposition and / or electrosynthesis and / or an electro-Fenton type process, and / or

- generation, by a conversion means, of electrical energy from the movement of the at least one electro-blade, and / or

a supply of at least one electro-blade with the electrical energy generated by the conversion movement.

It can be understood by advanced electro-oxidation a process implemented by means of an anode exhibiting a strong oxygen evolution overvoltage, typically greater than 1.9 volts compared to the normal hydrogen electrode (ENH) ( 1.9V / ENH), thus making it possible to produce powerful oxidants such as hydroxyl radicals which will be available for the degradation and mineralization of effluents. Conversely, non-advanced electro-oxidation can be understood as a process implemented by means of an anode exhibiting a low oxygen evolution overvoltage, typically less than 1.9 V / ENH. In this case, the available quantity of powerful oxidants such as hydroxyl radicals is limited or even zero. According to the same reasoning, it can be understood by advanced electro-reduction a process implemented by means of a cathode exhibiting a strong hydrogen evolution overvoltage, typically greater, in absolute value, than | -0.5 V / ENH | , which makes it possible to produce powerful reducing agents (example: superoxide ion) which will be available for the degradation and mineralization of effluents. Conversely, non-advanced electro reduction can be understood as a process implemented by means of a cathode exhibiting a low hydrogen evolution overvoltage, typically lower, in absolute value, than | -0.5 V / ENH | . In this case, the available quantity of powerful reducing agents is limited or even zero.

The at least one electro-blade can exert a pushing force on the fluid.

Preferably, the method comprises applying a force to the at least one electro-blade by the moving fluid in which the at least one electro-blade is immersed.

Preferably, the tangential flow and / or the radial flow and / or the axial flow of fluid at the level of at least part of a surface of the electro-blade are generated concomitantly.

Preferably, the tangential flow and / or the radial flow and / or the axial flow of fluid at the level of at least part of a surface of the electro-blade are generated by:

- the setting in motion of the fluid by at least one electro-blade, and / or

- the setting in motion of at least one electro-blade by the fluid.

Preferably, the fluid is set in motion by the at least one electro-paddle relative to the support unit and / or to the connecting element and / or to the at least one electro-paddle.

Preferably, the at least one electro-blade is set in motion by the fluid relative to the support unit and / or to the connecting element and / or to the at least one electro-blade.

The setting in motion of at least one electro-blade can be operated:

- by hydraulic pressure exerted on at least one electro-blade, and / or

- By application of a force, on the at least one electro-blade, by means of a device for setting in motion to which the at least one electro-blade is connected.

Preferably, the hydraulic pressure is exerted on the at least one electro-blade by a flow of moving fluid, for example by the effluents to be treated, in which the at least one electro-blade is immersed. The support unit may include the device for setting in motion to which the at least one electro-blade is connected. Preferably, the device for setting in motion is a device capable of exerting a force on the connecting element. Preferably, the device for setting in motion is a device designed to set the connecting element in rotation. The device for setting in motion can be a thermal or electric motor. Preferably, the device for setting in motion is an electrical machine with a support unit, able to operate in motor mode or in generator mode, to which the at least one electro-blade is connected.

The device according to the invention is preferably designed to implement the method according to the invention. Preferably, the device according to the invention is specially designed and arranged to implement the method according to the invention. Thus, any characteristic of the method according to the invention can be integrated into the device according to the invention.

Preferably, the method according to the invention is implemented by the device according to the invention. Preferably, the device according to the invention is specially designed and arranged to implement the method according to the invention so that any characteristic of the device according to the invention can be integrated into the method according to the invention.

Description of figures

Other advantages and features of the invention will become apparent on reading the detailed description of implementations and embodiments which are in no way limiting, and from the following appended drawings:

[Fig. 1] Figure 1 is a schematic side view of the device according to the invention,

[Fig. 2] Figure 2 is a schematic side view of the device according to the invention,

[Fig. 3] FIG. 3 illustrates a schematic representation in side view of an electro-blade according to the invention,

[Fig. 4] FIG. 4 is a graph showing the change in the amount of total organic carbon and total nitrogen as a function of time during the treatment of river water by the device according to the invention and by commercial disinfection tablets , [Fig. 5] FIG. 5 is a histogram illustrating the kinetic constant of degradation of paracetamol associated with the treatment of an aqueous solution of paracetamol by the device according to the invention, of a conventional electrochemical electro-oxidation assembly and of a filter -press, [Fig. 6] FIG. 6 is a graph showing the evolution of the quantity of paracetamol as a function of time during the treatment of an aqueous paracetamol solution by means of the device according to the invention and of a conventional electrochemical electro-oxidation assembly. ,

[Fig. 7] FIG. 7 is a graph illustrating the quantity of energy consumed as a function of time by the device according to the invention and by a filter press during the treatment of an aqueous solution of paracetamol under the same electrochemical conditions.

Description of the Embodiments Since the embodiments described below are in no way limiting, it is possible in particular to consider variants of the invention comprising only a selection of characteristics described, isolated from the other characteristics described (even if this selection is isolated at the same time). within a sentence comprising these other characteristics), if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art. This selection comprises at least one characteristic, preferably functional without structural details, or with only part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art. .

With reference to FIGURES 1 and 2, an electrochemical device 1 is described for the electrochemical treatment of effluents according to the invention. The device 1 comprises at least one electro-blade 2, two electro-blades 2 in the embodiment presented in FIGURES 1 and 2. Each electro-blade 2 comprises two electrodes 3 separated by a spacer 4 having a thickness between 1 and 1000 µm, this thickness is 500 µm in the embodiment shown in FIGURES 1 to 3. Each electro-blade 2 is movably mounted on a support unit 6 which is a rotating collector (or connector) 6 according to the embodiment. The device 1 comprises a connecting element 5, on which the electro-blades 2 are fixed. According to the embodiment presented, the connecting element 5 is a transmission shaft 5 which is arranged to be rotated and to be rotated. transmitting a force torque from the rotating collector 6 to the electro-blades 2 or vice versa. The transmission shaft 5 is connected, by means of a fixed link, to the support unit. The transmission shaft 5 is arranged to transmit a force from the rotating manifold 6 to the electro-blades 2 or vice versa.

According to the invention, each electro-blade 2 forms a non-zero angle with the direction or directions in which each electro-blade 2 is movable. That is to say that a surface 7 along which each electro-blade 2 mainly extends forms a non-zero angle with the direction or directions in which each electro-blade 2 is movable. In other words, in the case of a rotation of the electro-blades 2 around an axis 8, as presented according to the embodiment, the surface 7 forms a non-zero angle with respect to a plane 9 perpendicular to the axis of rotation 8.

According to the embodiment, the surfaces 71 of each electrode 3 in contact with the effluent to be treated are identical. The surfaces 71 are flat. The surfaces 71 are parallel to the surface 7 along which mainly extends each electro-blade 2. In other embodiments, these surfaces 71 may be different from one electro-blade 2 to another and / or within the same electro-blade 2 and may be different from the surface 7 along which mainly extends the electro-blade 2.

According to the invention, each electro-blade 2 is arranged, relative to the transmission shaft 5, so that a minimum angle formed between the surface 7 or at least part of the surface 7 or each point of the surface 7 of at least one electro-blade 2 and the direction or directions in which the transmission shaft 5 mainly extends is less than 85 °. According to the embodiment, the connecting axis 8 extends along a straight line 8 which coincides with the axis of rotation 8. Each electro-blade 2 extends, at least in part, in a radial direction with respect to to the connecting axis 8. According to the embodiment, each electro-blade 2 extends from the transmission shaft 5 mainly in a radial direction with respect to the connecting axis 8. According to the invention, the spacer 4 is arranged to allow the diffusion of the species between the two electrodes 3 of the electro-blades 2. The spacer 4 comprises a porous solid material. According to the embodiment, the spacer 4 is made of nylon 500 μm thick. The diameter of the pores of the spacer 4 is approximately 1 mm.

The thickness of the spacer 4 according to the invention makes it possible, in particular, to generate highly reactive species without adding species to the solution to be treated. By way of example, the reactive species generated at the anode can respectively be hydroxyl radicals, ozone and / or hypochlorite ions, chlorine dioxide and / or persulfate and / or percarbonate and / or perphosphate. These species can be generated respectively from water and / or chlorine and / or sulphated species and / or carbonate species and / or phosphate species present in the effluent to be treated without it being required. to add additional reagents.

According to the embodiment presented, the device 1 comprises a generator 10 arranged to supply the electro-blades. Each electrode 3 of each electro-blade 2 is supplied in mono-polar mode. According to the embodiment, and with reference to FIGURE 3, the electro-blade comprises a perforated anode 32 made of stainless steel. The perforations 321 of the anode 32 have a diameter of 5 mm. The perforations 321 of the anode 32 are spaced approximately 6mm lengthwise and crosswise. The cathode 31 is made of carbon felt and has a specific surface area of the order of 0.6 m ² .

The electro-blade 2 (the set of electrodes 3 and spacer 4) is porous and arranged so that the effluent and, at least part, of the species (pollutants or products to be treated (to be degraded, to be eliminated or to precipitate) contained in the effluent pass through the electro-paddle 2 during the movement of the latter in the effluent to be treated. In other words, the setting in motion of the electro-paddles generates an effluent flow 13 passing through the electro-blades 2. According to the embodiment, the cathode 31 is positioned on the side of the effluent flow 13,131 entering the electro-blade 2 and the anode 32 is positioned on the side of the effluent flow 13,132 leaving the electro-blade 2. In other words, considering the direction 14 in which the electro-blade 2 is mobile, the electro-blade 2 successively comprises the anode 32, the spacer 4 and the cathode 31. This arrangement improves the efficiency of the device 1 by forcing the species generated by electrochemistry at the cathode 31 to move towards the anode 32. Thus, the species reactive species, which by definition have a short lifespan, generated electrochemically at cathode 31 reach anode 32 before they are deactivated.

According to the embodiment, each electro-blade 2 is an assembly. The electrodes 3 and the spacer 4 are removable and interchangeable depending on the intended application, for example depending on the composition of the effluent to be treated and the treatment method used. Thus, the distance between the electrodes 3 can be modulated as needed by changing the spacer 4, the thickness of the spacer 4 and the electrodes 4.

By way of example, the electro-blade 2 can be assembled by means of a fixing system (not shown), for example a system of screws and tapped holes in one or more electrodes 3, by clamping the spacer 4 between the two electrodes 3 so that the electro-blades 2 each form an integral unit in one piece.

According to the invention, the electrochemical effluent treatment process comprises:

- an application of a potential difference or an injection of a current between the two electrodes 3 of the electro-blades 2,

- A setting in motion in a fluid, which is the effluent to be treated or the effluent during treatment according to the invention, of the electro-blades 2 in one or more directions.

The method comprises the step of forming a non-zero angle between the electro-blades 2 and the direction (s) in which the electro-blades 2 are set in motion.

According to the invention, the method comprises, during the setting in motion of the electro-blades 2, an application of a force by the electro-blades 2 on the effluent so as to impart a movement, in one or more determined directions. , to the effluent. This allows efficient and controlled agitation of the effluent. The force exerted by the electro-blades 2 on the effluent generates a tangential flow and a radial flow of the effluent at the level of the surface 7 of the electro-blade 2.

The setting in motion of the electro-blades 2 is effected by applying a force by means of a device for setting in motion to which the electro-blades 2 are connected via the transmission shaft 5. According to the embodiment, the device for setting in motion is the rotating collector 6 which is arranged to set the electro-blades 2 in rotation via the transmission shaft 5.

The setting in motion of the electro-blades 2 in the effluent helps to eliminate any clogging of the electrodes 3 by the entrainment of gases (gas bubbles), such as H2 and O2, generated by electrochemistry at the electrodes 3. The bubbles of gases entrained by the movement of the electro-blades 2, and therefore of the electrodes 3, act as unclogging. In addition, the presence of these gas bubbles at the surface limits the transfer of material to the surface of the electrodes 3. The entrainment of these gas bubbles when using the device 1 according to the invention makes it possible to increase. the transfer of material to the surface of the electrodes 3. The entrainment of these gas bubbles is not, or little obeyed, during the setting in motion of the effluent as is the case in the devices of the 'state of the art.

By way of non-limiting example, there is illustrated in FIGURE 2 a particular embodiment of the device 1 according to the invention. In FIGURE 2, anti-vortex elements 12 are shown in the form of an annular cylindrical wall, to which are fixed, for example every 90 °, rectangular counter-blades, extending on the outer part of the wall. a tank 11 in which the electro-blades 2 is intended to be immersed. There is also illustrated the diameter D of the treatment tank 11 intended to receive the effluents to be treated, the diameter d 'of the transmission shaft 5, the diameter d represents the distance separating the two radial ends of the electro-blades 2, H the height of effluents that the tank 11 is intended to receive, W the height of the electro-blades 2, Y the distance separating the lower edge of the electro-blades blades 2 from the bottom of the tank 11, L the radial length of the electro-blades 2, i.e. the distance separating the transmission shaft 5 from the radial ends of the electro-blades 2, b the thickness of l 'anti-vortex element 12 and b' the distance separating the anti-vortex element 12 from the p aroi of the tank 11. Always according to this non-limiting embodiment, the proportions presented below make it possible to obtain particularly advantageous performances, in particular in terms of transport and transfer of material: H is equal to D, D is equal to ((3/2) . d), d is equal to 5.W, D is equal to 3. Y, d is equal to 2.5L, d 'is equal to (d- (2.L)), b is equal to 0.1 . D and b 'is equal to 0.02. D. In addition, the surface 7 of the electro-blades 2 form an angle of between 30 and 45 ° with respect to the connecting axis 8.

The device 1 according to the invention, called “ELR” in the remainder of the description, from which the results presented in FIGURES 4 to 7 were obtained, comprises a cathode 31 made of carbon felt 14 cm ² of geometric area, of trade name “RGV2000®” produced by the company Mersen, a Niobium anode 32 comprising a diamond coating doped with boron 12 μm thick and having a geometric surface area of 14 cm ² which is produced by the company DiaCCon and a spacer 4 of 500 μm thick nylon separating the anode 32 from the cathode 31.

With reference to FIGURE 4, the electrolysis treatment implemented by the ELR device 1 according to the invention is compared to the treatment carried out by commercial disinfection tablets based on “sodium troclosene” (C3Cl2N3Na03), at a mass concentration of 99.8 mg of sodium tro closene per gram of lozenge, and silver, at a concentration of 1.8 mg of silver per gram of lozenge. These lozenges bear the commercial name of “Katadyn®”. River water from the Moselle was treated by the ELR device 1 according to the invention and by the Katadyn tablets.

During the electrolysis treatment implemented by the ELR device 1 according to the invention, a decrease in the total amount of organic carbon (TOC) is observed. At the same time, 50% mineralization is obtained after 8 hours of treatment. The amount of total nitrogen (NT) also decreased and 20% nitrogen was removed by conversion to the volatile nitrogen species. During treatment with Katadyn® lozenges, the TOC and NT contents increase with the lozenges. In addition, it is known that the mineralization capacities are zero with disinfectant tablets. Indeed, the pas- Disinfectant filters are known to have disinfecting power only and, in addition, to produce toxic organohalogenated by-products. The results presented below, as illustrated in FIGURES 4 to 7, were obtained by the ELR device 1 according to the invention. The speed of rotation of the electro-blades 2 is 35 rotations per minute (rpm).

These results were compared with the results obtained by a filter press (FP) comprising the same electrodes 3 (anode and cathode) as those of the device 1 as described above. The distance between the anode and the cathode of the filter press is 500 µm. A filter press is a static electrochemical cell which comprises an anode and a cathode separated by a space inside which a flow of effluents to be treated passes by means of a pump. The results obtained by the ELR device 1 according to the invention were also compared with the results obtained by a conventional electrochemical device (DC) comprising the same materials of electrodes 3 (anode and cathode) as those of the device 1 as described below. above arranged face to face and separated by a distance of 500 µm. In this case, the stirring of the solution to be treated was carried out by means of a magnetic stirrer at a speed of 500 rpm.

A first test illustrates the results obtained for the treatment of an aqueous solution of paracetamol by electro-oxidation. Paracetamol is a wastewater pollutant. The solution includes a sodium sulfate carrier electrolyte. The paracetamol is at a concentration of 0.1 mM, the solution is maintained at a pH of 7 and the conductivity of the solution is 850 pS / cm. The total volume of treated solution is 4 liters. The current injected during the treatment is 200 mA.

With reference to FIGURE 5, there is illustrated the degradation kinetic constants (k) of paracetamol associated with each of the three devices. The constant k associated with the DC device is 790 min ^-1 , that associated with the FP device is 3200 min ¹ and that associated with the ELR device 1 according to the invention is 4240 min ^-1 . This result denotes the improvement made by the invention in terms of material transport and therefore treatment efficiency.

With reference to FIGURE 6, the difference between the reduction in the total concentration of paracetamol obtained by the ELR device 1 according to the invention and that obtained by the DC device is illustrated. It is noted that the quantity of paracetamol in solution decreases much more rapidly with the ELR 1 device than with the DC device. This result illustrates the gain obtained in terms of kinetics and degradation rate obtained by using the ELR device 1 according to the invention.

FIGURE 7 shows the difference in terms of energy consumption used during the treatment between the ELR device 1 according to the invention and the FP device. Note that for a treatment time of 90 minutes, the energy consumption of the FP device is twenty times higher than that of the ELR device 1 according to the invention.

Thus, in variants that can be combined with one another of the embodiments described above:

- the support unit 6 is:

• a motor on which is mounted, pivotally movable, the connecting element 5 so as to rotate, for example in the plane of FIGURE 1, at least one electro-blade 2; in this case no rotating collector is required, and / or · a rail on which is movably mounted the connecting element 5 so as to set in motion the at least one electro-blade 2; in this case no slip ring is required, and / or

- the link element 5 is connected, by means of a movable link, to the support unit 6, and / or - the device 1 comprises a conversion means (not shown) arranged to convert a movement of the au at least one connecting element 5 in electricity intended to supply electrically the at least one electro-blade 2, and / or

- the device 1 comprises an electric machine (not shown) capable of operating in motor mode and / or in generator mode, the connecting element 5 being connected to a rotor of the electric machine, and / or

- the device 1 comprises several electro-blades 2 extending, at least in part, radially from the transmission shaft 5 and distributed along the transmission shaft 5 along the connecting axis 8, and / or - the electrochemical effluent treatment process comprises setting the fluid in motion in which the at least one electro-blade is immersed, and / or

a material of one or each of the electrodes 3 of an electro-blade 2 is different from a material of one or each of the electrodes 3 of another of the electro-blades 2, and / or

the method comprises the step of forming a non-zero angle between the electro-blades 2 and one or more directions in which the effluent to be treated is in motion, and / or

- The method comprises, during the setting in motion of the electro-blades 2 an application of a force by the effluent to be treated on the electro-blades 2 so as to set the electro-blades 2 in motion or to modify, amplify or oppose the movement of the electro-blades 2, and / or

- the process comprises:

• electrocoagulation and / or electro-flotation and / or electro-sorption and / or electro-oxidation, advanced or not, and / or electro-reduction, advanced or not, and / or electro-precipitation and / or electrodeposition and / or an electrosynthesis and / or an electro-Fenton type process, and / or

• a generation, by a conversion means, of electrical energy from the movement of the electro-blades 2, and / or · a supply of the electro-blades 2 with the electrical energy generated by the conversion means, and / or

- The setting in motion of the electro-blades 2 is operated by hydraulic pressure exerted by the fluid (or the flow of fluid) in motion on the electro-blades 2.

In addition, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations as long as they are not incompatible or exclusive of each other.

Claims

1. Electrochemical device (1) for the electrochemical treatment of effluents comprising at least one electro-blade (2), the at least one electro-blade comprising two electrodes (3) separated by a spacer (4) having a thickness between 1 and 1000 µm, preferably between 20 and 800 µm, more preferably between 50 and 500 µm, said at least one electric blade being movably mounted on a support unit and a surface (7) according to which s' mainly extends the at least one electro-blade forms a non-zero angle with the direction (s) in which the at least one electro-blade is movable.

2. Device (1) according to claim 1, comprising a connecting element (5) on which is fixed the at least one electro-blade (2), the connecting element is:

- connected, by means of a fixed or movable link, to the support unit, and - arranged to transmit a force from the support unit to the at least one electro-blade or vice versa.

3. Device (1) according to claim 1 or 2, wherein the non-zero angle formed between the at least one electro-blade and the direction or directions in which the at least one electro-blade is movable is. between 10 and 80 °.

4. Device (1) according to claim 2 or claim 3 taken in conjunction with claim 2, wherein at least one electro-blade (2) is disposed, relative to the connecting element (5), so that a minimum angle formed between a surface (7) or at least a part of the surface or each point of the surface of the at least one electro-blade and an axis along which mainly extends the element of link, said link axis (8), is less than 85 °.

5. Device (1) according to any one of the preceding claims, in which the spacer (4) is arranged to allow the diffusion of the species between the two electrodes (3) of the at least one electro-blade (2). .

6. Device (1) according to any preceding claim, wherein the spacer (4) comprises a porous solid material.

7. Device (1) according to claim 4 or any one of claims 5 to 6 taken in combination with claim 4, wherein the at least one electro-blade (2) extends, at least in part , in a radial direction relative to the connecting axis (8).

8. Device (1) according to claim 2 or any one of claims 3 to 7 taken in combination with claim 2, comprising conversion means arranged to convert a movement of the at least one connecting element (5 ) with electricity intended to supply electrically at least one electro-blade (2).

9. Device (1) according to claim 2 or any one of claims 3 to 8 taken in combination with claim 2, wherein the at least one connecting member (5) is a transmission shaft arranged to be rotated and to transmit a torque from the support unit to the at least one electro-blade (2) or vice versa.

10. Device (1) according to any one of the preceding claims, comprising several electro-blades (2), a material of one or each of the electrodes (3) of an electro-blade being different from a material of 'one or each of the electrodes of another of the electro-blades.

11. Device (1) according to claim 2 or any one of claims 3 to 10 taken in combination with claim 2, comprising:

- an electric machine capable of operating in motor mode and / or in generator mode, the connecting element (5) being connected to a rotor of the electric machine, and / or

- a rotating connector (6) on which the connecting element is mounted.

12. Device (1) according to any one of claims 1 to 11, comprising a generator (10) arranged to supply at least one electro-blade (2).

13. A process for the electrochemical treatment of effluents comprising:

- an application of a potential difference or an injection of a current between two electrodes (3) of at least one electro-blade (2) movable in one or more directions, the electrodes of at least one electro- blade being separated by a spacer (4) having a thickness between 1 and 1000 μm and a surface (7) along which extends mainly the at least one electro-blade forms a non-zero angle with the direction (s) according to the which at least one electro-blade is mobile,

- a setting in motion in a fluid of at least one electro-blade in one or more directions, and / or - a setting in motion of the fluid in which the at least one electro-blade is immersed.

14. The method of claim 13, comprising a step consisting in forming: - a non-zero angle between the at least one electro-blade (2) and the direction or directions in which the at least one electro-blade is. setting in motion, and / or

a non-zero angle between the at least one electro-blade and one or more directions in which the fluid is moving.

15. The method of claim 13 or 14, comprising, during the setting in motion of the electro-blade (2):

- an application of a force by the at least one electro-blade on the fluid, and / or - an application of a force by the fluid on the at least one electro-blade, and / or

- a setting in motion of the fluid by at least one electro-blade, and / or

- a setting in motion of at least one electro-blade by the fluid, and / or

- Generation of a tangential flow and / or a radial flow and / or an axial flow of fluid at the level of at least one surface (7) of the electro-blade.

16. A method according to any one of claims 13 to 15, comprising, during the setting in motion of the electro-blade (2) an electrocoagulation and / or electro-flotation and / or electro-sorption and / or an electro-sorption. -oxidation, advanced or not, and / or an electro-reduction, advanced or not, and / or an electro-precipitation and / or electrodeposition and / or an electrosynthesis and / or an electro-Fenton type process.

17. Method according to any one of claims 13 to 16, comprising, during the setting in motion of the electro-blade (2):

- generation, by a conversion means, of electrical energy from the movement of the at least one electro-blade, or

a generation, by a conversion means, of electrical energy from the movement of the at least one electro-blade and a supply of the at least one electro-blade with the electrical energy generated by the conversion means .

18. A method according to any one of claims 13 to 17, wherein the setting in motion of the at least one electro-blade (2) is carried out: - by hydraulic pressure exerted on the at least one electro-blade, and or