DE10057347C2 - Device for decontaminating, in particular, heavy metals and / or arsenic and / or their compounds, from water - Google Patents

Description

The invention relates to a device for Decontamination of heavy metals in particular and / or Arsenic and / or their compounds from water.

The removal of heavy metals in particular and / or Arsenic and / or their compounds from water for production of drinking water is currently only unsatisfactory possible. The pollution of the drinking water with z. B. Arsenic is particularly in regions with accordingly contaminated groundwater mostly near or above the permissible values. There are already numerous devices known for the purification of water, but with respect to the Arsenic removal are not effective. For example, DE 33 36 460 A1 describes a method and an apparatus for Purification of water by means of electrolysis, which too cleaning water on electrodes from 2- or 3-valued Metals of different polarity is passed. Iron or is preferably used as the electrode material Aluminum used.

It is still a facility for processing Waste water known by means of electrolysis, in which  alternating electrodes made of steel and aluminum can be combined (DE 43 15 117 A1) or iron and / or Find aluminum electrodes application (DE 43 29 272 C1). The However, use of aluminum electrodes has a high one pH value, which is particularly negative removal of arsenic.

In this respect, the pH value is more favorable in the solutions disclosed in DE 694 16 698 T2, WO 99/11577 A1, DE-OS 22 01 070 and JP 7- 256272 A, in which carbon dioxide is used. The CO ₂ is generated by the use of graphite electrodes or supplied from the outside during the electrolysis. However, the composition of the electrodes used is not optimal in order to achieve a low pH and thus a high degradation of arsenic. The fixed, immovable arrangement of the electrodes is extremely disadvantageous in all devices of the prior art. This makes their handling particularly difficult when maintaining and cleaning the device.

The object of the invention is a device for Decontamination, especially heavy metals and / or arsenic and / or their compounds from water by electrolysis develop which one without polluting the environment high arsenic degradation with good efficiency guaranteed and with a simple technical structure quick and easy maintenance of the electrodes.  

This object is achieved by the features of 1. Patent claim solved.

The device for decontaminating, in particular, heavy metals and / or arsenic and / or their compounds from water by electrolysis has a container in which electrodes of different polarity are arranged, a combination of electrodes

• - made of iron, aluminum and graphite

or

• - Made of aluminum and graphite

Application.

The electrodes are towards the bottom of the container with their Bottom in spaced groove-shaped electrically insulated recesses and added to their opposite side by single electrical insulating spacers spaced from each other, wherein the spacers attached to the electrodes and the Electrodes in the groove-shaped recesses unfolded are stored.

The electrodes are preferred in a frame added to the towards the bottom of the tank has groove-shaped recesses. The electrodes are inclined at an angle to the vertical container wall and are against a stop on the frame.

The spacers are preferred on the electrodes releasably attached. To do this, they either become bracketed or nub-shaped.  

The spacers are preferably via a rope or a Chain linked together. You can continue Have projections that in corresponding recesses of the Intervene electrodes.

Depending on its size, one or several frames with plate-shaped electrodes arranged his. They are aligned in the direction of flow or to the direction of flow at a defined angle sloping.

The ratio of the number of aluminum electrodes: iron electrodes: graphite electrodes is 60-96: 2-30: 2-30 or the ratio of aluminum electrodes: graphite electrodes 60-98: 2-40.

With the solution according to the invention, one becomes constructive relatively simple device for decontaminating especially heavy metals and / or arsenic and / or their Connections created from drinking water. It will through the use of graphite electrodes and in particular by realizing a certain relationship of electrodes used possible to adjust the pH of the to bring cleaning water to a level which Oxidation of toxic substances favors. The number the various electrodes (iron, aluminum, graphite) can easily be determined by appropriate tests. In certain cases it is also possible to use electrodes to do without iron.  

By attaching the electrodes by means of groove-shaped Formations on the lower side of the floor and individual Spacers on the top of the electrodes can these are opened individually and moved against each other. The plate-shaped electrodes are simply inserted into the Recesses of the frame used and on the opposite side by spacers from each other spaced. The spacers are z. B. bracket-shaped (U-shaped) and become simple stuck over the upper edge of the electrode. Preferably two spacers (right and left) attached. It is also possible to use the spacers only to be provided on every second plate.

The first plate that is used can be easy be placed at an angle to a stop on the frame, which eliminates the need for complex position fixation. The special design of the device ensures a easy handling and assembly as well as with little effort feasible maintenance.

The invention is based on Exemplary embodiments and associated drawings explained.

Show it:

Fig. 1 frame for insertion of the electrodes,

Fig. 2 electrodes with spacers in side view,

FIG. 2a clip,

Fig. 2b electrodes acc. Fig. 2 in side view,

Fig. 3 unfolded electrodes,

Fig. 4 combination of electrodes made of different materials,

Fig. 5 top view of a container having 4 frames,

Fig. 6 section AA through the container.

In Fig. 1, a frame 1 is shown with four vertical struts 1.1 . Two shorter horizontal second struts 1.2 and two longer horizontal third struts 1.3 are arranged in the direction of the floor between the vertical first struts 1.1 . In the longer horizontal third struts 1.3 there are groove-shaped recesses N, so that these struts 1.3 are comb-like. Opposite horizontal fourth struts 1.4 are arranged in alignment at the upper end of the first struts 1.1 above the horizontal second struts. Two further horizontal fifth struts 1.5 run at right angles to it. on the fourth strut shown here on the right are two stops 2 . intended. It is indicated by dashed lines that a plate-like electrode 3 is mounted in the grooves N. The electrode 3 lies against the stops 2 at an angle α. However, it is also possible for a fourth strut 1.4 of the frame 1 to serve directly as a stop 2 for the first electrode 3 . Furthermore, a plurality of mutually parallel struts 1.3 with mutually aligned grooves N can be arranged in the base region in order to ensure a more stable positioning of the electrodes 3 . Alternatively, a base plate (not shown) with grooves N can also be used.

The electrodes 3 thus sit on their lower edge 3.1 in the grooves N. The upper edges 3.2 are gem. Spaced Fig. 2 and 2b by means of spacers 4 (see. Fig. 2a) in the manner of brackets from each other. In FIG. 2 this is the side view and in Fig. 2b shows the front view of the electrode 3 with spacers 4. The spacers 4 are U-shaped, engage with their two parallel legs 4.1 over the upper edge 3.2 of the electrode 3 and determine the upper distance of the electrodes 3 by the width b of the parallel legs 4.1 . In order to ensure a parallel arrangement of the electrodes, the width L1 of the legs 4.1 of the spacers 4 must correspond approximately to the distance L2 of the grooves N. It is sufficient if spacers 4 are only arranged on every second electrode. In order not to cause a short circuit, the spacers 4 consist of an electrically non-conductive material, e.g. B. plastic. The frame should also be made of an electrically non-conductive material or be encased with it, e.g. B. plastic coated. The spacers 4 can be connected to one another with a rope 5 or a chain. The rope 5 is guided, for example, through a bore 4.2 of the spacer 4 .

In Fig. 3 it is shown schematically that the flexible storage of the electrodes 3 in the grooves N can be easily unfolded to carry out any maintenance or cleaning work. A possibility of combining electrodes made of different materials is shown in FIG. 4. A total of 20 electrodes are provided in a frame, 16 electrodes made of aluminum in a first region, 2 electrodes made of iron in region b and 2 electrodes in region c are made of graphite. The ratio of the number of electrodes made of aluminum to electrodes made of iron to electrodes made of graphite is therefore 80:10:10. In this example, a spacer 4 was attached to each electrode 3 . The width L1 of the mutually parallel legs 4.1 has been adjusted accordingly. There was no rope in this variant.

The grooves have not been shown in FIGS. 3 and 4.

An arrangement of a total of 4 frames 1 with electrodes 3 in a round container 6 is shown in FIG. 5 in plan view and FIG. 6 in section AA according to FIG. Fig. 5. The four frames 1 are each offset by 90 ° to each other. A stirrer 7 is provided in the container 6 for circulating the water W to be cleaned.

The supply line 8 for the water to be cleaned and a separate discharge line 9 of the clear phase and a discharge line 10 of the sludge phase are present, the pump 11 being arranged between the supply line 8 and the discharge lines 9 , 10 . A water supply 12 leads from the pump 11 into the container 6 . Furthermore, there is a suction 13 for pumping out the clear phase and a suction 14 for pumping out the sludge phase, which are also connected to the pump 11 . A shut-off valve 16 is additionally provided behind the pump 11 .

The valves are arranged as follows:

• a valve V1 in the feed line 8 before the suction 13 and 14 of the pump,
• a valve V2 between the suction 13 of the clear phase and the pump 11 ,
• a valve V3 between the suction 14 of the sludge phase and the pump 11 ,
• a valve V4 between the pump 11 and the water supply 12 to the container 6 ,
• - In the derivative 9 of the clear phase, a valve V5

and

• - In the discharge 10 of the sludge phase, a valve V6.

To fill the container 6 with the water W to be cleaned, the valves V1 and V4 are open and the valves V2, V3, V5, V6 are closed. The water W thus flows through the supply line 8 via the pump 11 and the water supply 12 into the container.

After the cleaning process, while maintaining the current flow in the electrodes 3 and thereby forming a flake layer 17 on the water W, the clear phase of the water is pumped out of the container until the flake layer has reached a certain low point. For this purpose, the valves V2 and V5 are open and the valves V1, V3, V4, V6 are closed, as a result of which the water is led via the suction 13 and the pump 11 to the discharge line 9 for the clear phase.

Now the valves V3 and V6 are opened to pump out the sludge phase from the bottom region of the container, the valves V1, V2, V4, V5 being closed. Due to the suction 14 reaching into the middle of the bottom of the container 6 , the flake sludge is led via the pump 11 to the discharge line 10 for the flake sludge.

In FIG. 6, the height level for the water supply 12, shown for the suction 13 of the clear phase and for the extraction 14 of the slurry phase.

Alternatively, it is also possible, in the case of flakes that have sunk to the bottom area of the container 6, to first suction this flake sludge with the suction 14 and to convey it to the discharge 10 and then to promote the clear phase with the same suction 14 to the discharge 9 for the clear phase. The valve control must be adjusted accordingly. Different suction systems can also be used to extract the sludge and clear phases.

Instead of a round container there are also others Container shapes, e.g. B. elongated basin in the manner of a Swimming pool, can be used.

The connections of the electrodes were in the aforementioned Embodiments and drawings not specified. Usually these are alternating between a plus and Negative pole connected.

The water W to be cleaned flows through the circulation movement of the stirrer 7 through the electrodes 3 of different polarity for a defined period of time (2 to 120 minutes) at 2 to 24 V and 100 to 10000 A, the heavy metals and / or arsenic being produced by the electrolysis taking place and / or their compounds are oxidized. The flocculations rise to the surface and are then separated. A pH of 5.5 is advantageous for removing arsenic from water (especially drinking water).

By using electrodes 3 made of graphite in the area c, CO _{2 is} generated, which causes the pH to decrease. Alternatively, it would also be possible to supply the CO ₂ to the water W from the outside.

The flocculations rise to the water surface during the cleaning process and settle there in the manner of a flake layer 17 ( FIG. 6). In this state, as already described above, while maintaining the electrolysis, the clear phase is first pumped down to a preselected water level and then the remaining sludge phase located on the tank bottom is suctioned off. The clear phase is completely cleaned using a sand filter and during the sludge phase the water is separated from the flakes in a chamber filter press.

However, belt presses or automatic ones can also be used Quick filters are used.

Claims (12)

1. Device for the decontamination of, in particular, heavy metals and / or arsenic and / or their compounds from water by electrolysis with a container in which electrodes of different polarity are arranged,
being a combination of electrodes
made of iron, aluminum and graphite
or
made of aluminum and graphite
Applies,
and the electrodes are accommodated with their underside in the direction of the container bottom in spaced apart, groove-shaped, electrically insulated recesses and are spaced apart on their opposite side by individual electrically insulating spacers, the spacers being fastened to the electrodes and the electrodes being mounted in the groove-shaped recesses so as to be able to be opened apart. 2. Device according to claim 1, characterized in that that the electrodes are accommodated in a frame. 3. Device according to claim 2, characterized in that the frame towards the bottom of the container has groove-shaped recesses.   4. Apparatus according to claim 2 or 3, characterized characterized that the electrodes at an angle are inclined and rest on a stop of the frame. 5. Device according to one of claims 1 to 4, characterized characterized in that the spacers releasably attached to the Electrodes are attached. 6. Device according to one of claims 1 to 5, characterized characterized that the spacers are bracket-shaped are trained. 7. Device according to one of claims 1 to 5, characterized characterized that the spacers are knob-shaped are trained. 8. Device according to one of claims 1 to 5, characterized characterized that the spacer protrusions have, which in corresponding recesses of Intervene electrodes. 9. Device according to one of claims 1 to 8, characterized characterized that the spacers by a rope or a chain are connected.   10. Device according to one of claims 1 to 9, characterized characterized that multiple frames in one container are arranged. 11. The device according to one of claims 1 to 10, characterized characterized that the ratio of the number of Aluminum electrodes: iron electrodes: electrodes made of graphite 60-96: 2-30: 2-30. 12. The device according to one of claims 1 to 10, characterized characterized by the ratio of electrodes Aluminum: electrodes made of graphite 60-98: 2-40 amounts.