SK282156B6 - Replaceable compact operating electrode and three-electrode flow electrochemical cell with replaceable porous operating electrode - Google Patents

Abstract

Disclosed is a replaceable compact working electrode consisting of irregular particles of conductive material that is closed from two sides by a porous fabric, and a three-electrode flow electrochemical cell with a replaceable compact porous working electrode and a hydrodynamically separated compartment on the auxiliary and reference electrodes.

Description

Technical field

The invention relates to a replaceable compact working electrode and a flow-through electrochemical cell with a replaceable compact porous working electrode and a hydrodynamically separated space for the auxiliary and reference electrodes.

BACKGROUND OF THE INVENTION

Electrochemical cells are mainly used for analytical purposes to determine various substances. They are also used for electrochemical synthesis and for purification of solutions and waste water. The electrochemical efficiency of these targets depends primarily on the nature of the working electrode, the hydrodynamic conditions of the electrolysis, and the cell design. In particular, efficient electrolysis can be achieved in flow-through arrangements. There are basically two ways to achieve high electrochemical conversions in flowing solutions: a) Using thin film targets where the solution flows over the working electrode surface in a layer corresponding to the diffusion layer thickness, b) The solution flows through the porous electrode, where the total effective electrode area to volume ratio solution in contact with it can also be large. The first solution is technically very demanding and disadvantageous in terms of practical applications for the lengthy and cumbersome preparation and regeneration of the working electrode. Cells with flow-through porous electrodes may be easier to prepare, but there are considerable problems with their regeneration and homogeneity of the potential difference between the electrode and the solution in the electrode volume, which in fact depends on the electrochemical selectivity and cell efficiency. Another problem is the hydrodynamic separation of the auxiliary and reference electrode compartments from the treated solution, while ensuring a low ohmic resistance between them. Since the regeneration of porous electrodes, e.g. grinding and polishing the surface is virtually impossible, the worn electrode must be replaced with a new one. Replacing a worn electrode must therefore be simple and inexpensive.

SUMMARY OF THE INVENTION

These problems and drawbacks are overcome by the solution according to the invention, which is based on a replaceable compact working electrode consisting of irregular particles of an inert conductive material which is closed on two sides by a porous substance. In a preferred embodiment, the particle size is in the range of 1 to 1000 µm. Another advantageous embodiment is that the conductive contact is fastened to the electrode body.

The flow electrolysis is performed in the volume of this porous electrode. The electrode is compact and replaceable. The auxiliary and reference electrodes are separated from the working space by an ion exchange membrane.

Another embodiment of the present invention is a three-electrode flow electrochemical cell with a hydrodynamically separated auxiliary space in which the auxiliary and reference electrodes are located, said cell as a working electrode comprising a replaceable compact electrode having irregular pores to pass the solution to be subjected to electrochemical conversion. and an integrated auxiliary space with a replaceable body for the electrochemical reaction products of the auxiliary electrode that are hydrodynamically separated from the working electrode.

The electrochemical cell enables a new and higher electrolysis effect to be achieved by designing the turbulence of solution flowing through the electrode pores, even at lower flow rates, due to irregular and sharp edges of particles of different sizes, thereby increasing the transfer rate and hence electrochemical efficiency. The flat disc shape of the electrode and the parallel auxiliary electrode ensure homogeneity of the working electrode potential and hence a high selectivity of electrolysis, similar to the use of small and geometrically suitably positioned electrodes. The working electrode is compact and easy to replace, allowing easy and quick replacement after wear.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show a cross-section of an electrochemical cell (Fig. 1) and an overall view thereof (Fig. 2).

DETAILED DESCRIPTION OF THE INVENTION

The removable disk working electrode 3 comprises an electrode material and a conductive contact inside. The electrode material is prepared from an electrically conductive material. The particle size is in the range of 1 to 1000 µm. The conductive contact is fixed to the electrode body. The electrode is closed on both sides with a porous substance. The auxiliary and reference electrodes are mounted in a replaceable body 8 which is inserted into the auxiliary space. The electrodes are fixed with parts 1, 10. Sealing rings 2, 4, 7 and 9 are used to seal the electrodes.

The sample solution or base electrolyte flows through the working electrode. The working space and auxiliary space are hydrodynamically separated from each other by means of an ion exchange membrane 6. This prevents the electrolyte or sample from being mixed with the auxiliary electrolyte and the products resulting from the electrochemical reaction at the auxiliary electrode.

The auxiliary space is filled with an auxiliary electrolyte, which is replaced as necessary via the inlets in the part 10.

The electrical contact of the electrodes is provided by the movable pushbuttons 12, 15 and 22, the spring bolts 13, 16 and 21 and the contacts 14, 17 and 20 screwed into the cell.

Industrial usability

Said cell is useful for analytical purposes, namely for detection and determination of electroactive substances, for cleaning solutions from heavy metals, as well as for electrochemical treatment of solutions, such as removal of organic substances by oxidative electrolysis. It is also useful for performing electrochemical syntheses.

Claims (4)

A replaceable compact working electrode, characterized in that it consists of irregular particles of an inert conductive material which is closed on two sides by a porous substance. A replaceable compact working electrode according to claim 1, characterized in that the particle size is in the range of 1 to 1000 µηι. SK 282156-6 A replaceable compact working electrode according to claim 1 or 2, characterized in that a conductive contact is fastened to the electrode body. A three-electrode flow electrochemical cell with a hydrodynamically separated auxiliary space containing an auxiliary and reference electrode, characterized in that it comprises, as a working electrode, a replaceable compact electrode (3) according to claim 1, which comprises irregular pores for solution passage; is to undergo an electrochemical conversion, and an integrated auxiliary space with a replaceable body (8) for electrochemical reaction products of the auxiliary electrode that are hydrodynamically separated from the working electrode.