SU1742218A1 - Apparatus for adsorption/desorption processes - Google Patents

Abstract

The essence of the invention is that the working electrode is made in the form of a roll of activated nonwoven carbon fiber material, provided with a metal mesh, laid between the layers of the roll and forming the outer shell of the electrode, and the device has a central metal perforated tube, 2 or more. Mt

Description

The invention relates to devices for adsorptive treatment of wastewater from organic impurities and the subsequent regeneration of the adsorbent and can be used to purify spent alkaline solutions and remove protective relief in the production of printed circuit boards.

The aim of the invention is to increase the efficiency of the device by providing a given potential throughout the volume of the adsorbent.

FIG. 1 shows a device, a longitudinal section; in fig. 2 shows section A-A in FIG. one.

The device contains a cylindrical conductive housing 1, which is an auxiliary electrode, with a housing 2 forming a jacket 3, through which heat carrier (water) can be passed to control the process temperature, and a replaceable working electrode 4 made of nonwoven carbon fiber in it, in the center of which metal perforated tube 5 passes to which a grid 6 of the same material is welded, which is with a current lead, a sandwich made of mesh and nonwoven activated carbon fiber material 7 is wound A reference electrode 8 is coaxially mounted inside the pipe 5. Inside the pipe 5, the electrode 8 is installed. The device is equipped with outlet nozzles of the solution 9, distribution devices 10-13 and nozzles of the input and output of the coolant 14 and 15, respectively.

The operation of the device can be divided into 2 cycles.

1 cycle of adsorption purification of spent alkaline solution.

The alkaline solution to be cleaned through the distribution device 10 and the pipe 5 enters the interior of the device, passes through an adsorbent - activated carbon fiber fabric, and is discharged through the connections 9 and the distribution device 12.

The housing 1, which serves as an auxiliary electrode, is connected to the positive pole of the external power source, and the pipe 5, to which the grid 6 is welded, is connected to the other pole.

A predetermined potential at the working electrode (carbon fiber material) is measured relative to the chlorine-secondary

WITH

WITH

h

4 GO

Yu

00

electrode 8, located in the geometric center of the electrode, using a direct current source - a potentiostat (it is not shown in Fig. 1), which allows the processes of adsorption - desorption in a potentiostatic mode

The working electrode 4 made of an activated carbon fiber material, as well as an auxiliary electrode, the device body, is fed from a potentiostat.

Next, adsorption under the conditions of electrochemical polarization of the activated carbon fiber material is carried out in a potentiostatic mode (in this case, in the potential range +0.15 -

+0.25 C).

The use of electrochemical treatment of the adsorbent in the anodic potential region (+ 0.15 - + 0.25 V) changes the interfacial tension at the phase boundary, and also reduces the electric charge of the surface of the carbon fiber material, which facilitates the adsorption of organic substances from alkaline solutions. . This allows the purification rate to be increased from 20 to 95-99%.

Both for any adsorption process, and for adsorption under the conditions of electrochemical polarization, when passing through an adsorbent - activated carbon fiber fabric - spent waste containing organic substances, the surface of the adsorbent can be completely filled with organic molecules, i.e. adsorbent surface saturation. With further transmission of the treated wastewater, there will be a leakage of organic substances, which will lead to a sharp decrease in the degree of adsorption treatment.

After the adsorbent is saturated with organic substances, the alkaline solution is stopped and the remaining solution inside the device returns by gravity back to the tank. Then the distribution devices 10 and 12 overlap.

U cycle adsorbent regeneration.

Through the switchgear 13, the device is filled with an electrolyte solution (in this case, 0.75-2.5 M sodium hydroxide solution) and the polarity of the electrodes is changed, i.e. the housing 1 is connected to the negative pole of the external current source, and the electrode is a positive pole and the regeneration of the activated carbon fiber material is carried out under the conditions of electrochemical polarization

potentiostatic mode (in this case, in the field of potentials -0.04 - -0.08

B) Water is passed through a shirt with a temperature of 50 ° C. In this case, the opposite effect is achieved - adsorption will be difficult, and organic substances will be desorbed from the adsorbent. In the process of polarization, the electrode surface is recharged due to the redistribution of the potential jump at the electrode – solution interface (the dependence of the electrode surface charge on the applied potential is described by the Lippmann equation). At the zero charge point (+0.15 - +0, 25 V) the maximum adsorption of organic substances is achieved, and when the potential of the La in the cathode region (-0.04 -0.08 V) is shifted, the surface charge of the adsorbent electrode increases, which leads to a change in the surface tension and desorption of organic matter. of substances from the adsorbent surface.

After the end of the regeneration cycle, the switchgear 11 is opened, the electrolyte is drained and the switchgears 11 and 13 are closed, and water with a temperature of 18-20 ° C is passed through the jacket.

And so the cycles are repeated.

The use of the proposed device provides in comparison with the prototype the following advantages:

1. The quality and speed of purification of solutions from organic impurities increases.

2. The number of adsorption-regeneration cycles is increased without changing the adsorbent.

3. The energy consumption per unit of concentration of removed organic pollutants is reduced by 1.3 times,

The adsorption-desorption processes of the proposed method are carried out at lower potential values (adsorption at potentials + 0.15 - +0.25 V; desorption at potentials -0.04 - -0.08 V) compared with the known method, resulting in lower power consumption for these processes.

Claims (1)

Claims The device for carrying out adsorption-desorption processes, comprising a cylindrical body with a fixed adsorbent layer, an electrode and a current source, characterized in that, in order to increase the efficiency of the device by providing a predetermined potential throughout the adsorbent, roll of activated non-woven carbon fiber material, equipped with a metal mesh, laid between the layers of the roll and forming the outer the shell of the electrode, and the central metal perforated tube to which the metal mesh is attached, while the tube is provided with a coaxially mounted reference electrode, and the housing with a jacket with nozzles for supplying heat transfer fluid, with the housing being connected to a current source. 0Y FIG. 2