Device for treating wastewater containing hexavalent chromium ions

Abstract

The utility model discloses a device for treating wastewater containing hexavalent chromium ions, which comprises an anode reaction zone, a cathode reaction zone, a buffer zone, an electrocoagulation reaction zone and an inclined tube settling zone which are communicated in sequence, a suspended partition plate is arranged between the anode reaction zone and the cathode reaction zone, a graphite plate array is arranged in the anode reaction zone, and the graphite plate array is arranged in the inclined tube settling zone. A porous carbon material is arranged in the cathode reaction zone, the cathode reaction zone is communicated with the buffer zone, the buffer zone is communicated with the electrocoagulation reaction zone, an iron pole plate array is suspended in the electrocoagulation reaction zone, the electrocoagulation reaction zone is communicated with the inclined tube settling zone, and the inclined tube settling zone is communicated with the inclined tube settling zone. And an inclined tube is suspended in the inclined tube settling region. According to the utility model, hexavalent chromium ions in water can be removed by only using electricity and a small amount of iron element, reducing agent chemicals and acid and alkali agents used for treating hexavalent chromium in the traditional process are greatly reduced, and the salt content of effluent is far lower than that of the traditional treatment process.

Description

TECHNICAL FIELD

[0001] The utility model relates to water treatment technical field, concretely is a device for treating wastewater containing hexavalent chromium ions. BACKGROUND

[0002] With the rapid development of modern industry, environmental problems gradually affect the normal life and development of human beings. Among them, heavy metal pollution is one of the most important pollutions in industry. Among the heavy metal pollutants, hexavalent chromium ions are common toxic heavy metals in wastewater, and the common sources of cadmium contaminated wastewater are electroplating, metallurgy, battery manufacturing and other industries. How to realize the economic and environmental protection and excellent adsorption performance of the adsorbent is one of the key factors for adsorbing and treating wastewater containing hexavalent chromium ions.

[0003] The existing hexavalent chromium ion removal process uses reducing agents for reduction, such as sodium bisulfate, which needs to be in an acid-base environment, and needs a large amount of acid-base reagent, and the salt content of the effluent is high.

[0004] Therefore, we propose a device for treating wastewater containing hexavalent chromium ions to solve the problems raised in the above. CONTENT OF THE UTILITY MODEL

[0005] The utility model aims at providing a device for treating wastewater containing hexavalent chromium ions to solve the problems raised in the above background.

[0006] To achieve the above purpose, the utility model provides the following technical scheme: a device for treating wastewater containing hexavalent chromium ions, comprising: an anode reaction zone, a cathode reaction zone, a buffer zone, an electric coagulation reaction zone and an inclined pipe precipitation zone connected in sequence;

[0007] A suspended partition is provided between the anode reaction zone and the cathode reaction zone, a graphite plate array is provided in the anode reaction zone, and at least one graphite plate anode parallel to the side wall is connected to the positive electrode of the external direct current power supply;

[0008] A porous carbon material is provided in the cathode reaction zone and connected to the negative electrode of the external direct current power supply;

[0009] A first water outlet is provided above the porous carbon material in the cathode reaction zone, and the first water outlet is connected to the buffer zone;

[0010] The buffer zone is connected to the electric coagulation reaction zone through a second water outlet, and an iron electrode plate array is suspended in the electric coagulation reaction zone;

[0011] A third water outlet is provided in the middle of the electric coagulation reaction zone, the third water outlet is connected to the inclined pipe precipitation zone, an inclined pipe is suspended in the inclined pipe precipitation zone, a plurality of hoppers are provided at the bottom of the inclined pipe precipitation zone, a sludge discharge port is provided at the bottom of the hopper, and a fourth water outlet is provided at the upper part of the inclined pipe precipitation zone.

[0012] Preferably, the anode reaction zone, the cathode reaction zone, the buffer zone, the electric coagulation reaction zone and the inclined tube precipitation zone are integrally connected by a box.

[0013] Preferably, the anode reaction zone is provided with a water inlet, an exhaust valve and a gas pressure gauge.

[0014] Preferably, the porous carbon material includes graphite sponge, graphene sponge, graphite felt, carbon material particle filler, and is connected with an external direct current power negative electrode.

[0015] Preferably, the number of the iron electrode plate array is not less than three, and the two electrode plates at the two ends are respectively connected with the positive electrode and the negative electrode of the direct current power source, and the electrode plate spacing is within 5-15mm.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] Only electricity and a small amount of iron elements can remove hexavalent chromium ions in water, greatly reducing the reducing agent chemicals, acid and alkali reagents used in the traditional process for treating hexavalent chromium, and the salt content of the effluent is far lower than that of the traditional treatment process. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 is a side perspective view of the utility model;

[0019] Fig. 2 is a top view of the utility model.

[0020] In the figure: 1, anode reaction zone; 2, graphite plate array; 3, water inlet; 4, exhaust valve; 5, gas pressure gauge; 6, cathode reaction zone; 7, first water outlet; 8, porous carbon material; 9, buffer zone; 10, electric coagulation reaction zone; 11, iron electrode plate array; 12, second water outlet; 13, third water outlet; 14, inclined tube precipitation zone; 15, fourth water outlet; 16, inclined tube; 17, hopper; 18, sludge outlet. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0022] Please refer to Figs. 1-2The utility model provides a technical scheme: a device for treating wastewater containing hexavalent chromium ions, comprising an anode reaction zone 1, a cathode reaction zone 6, a buffer zone 9, an electric coagulation reaction zone 10 and an inclined pipe precipitation zone 14 connected in sequence, and an integrated anode reaction zone 1, cathode reaction zone 6, buffer zone 9, electric coagulation reaction zone 10 and inclined pipe precipitation zone 14 box;

[0023] The anode reaction zone 1 and the cathode reaction zone 6 are integrated, and a partition plate is arranged between the anode reaction zone 1 and the cathode reaction zone 6, and the partition plate is arranged in suspension, so that the anode reaction zone 1 and the cathode reaction zone 6 are communicated at the bottom.

[0024] The anode reaction zone 1 is provided with a water inlet 3, an exhaust valve 4 and a gas pressure gauge 5 for water inlet, exhaust and gas pressure monitoring, respectively.

[0025] The anode reaction zone 1 is provided with a graphite plate array 2, at least one graphite plate positive electrode of which is installed in parallel to the side wall and connected to the positive electrode of an external direct current power supply, so that the anode reaction zone 1 generates a loop with the cathode reaction zone 6 to make electrons flow, and oxygen bubbles are generated on the surface of the graphite plate array 2 to generate an oxidation water reaction, so that the reaction of the cathode reaction zone 6 is not affected, the gas is released through the partition plate, and the chromium ions reduced from hexavalent to trivalent in the cathode reaction zone 6 are prevented from being oxidized by the anode again.

[0026] The surface reaction of the graphite plate array 2 in the anode reaction zone 1 is as follows:

[0027] 4H2O-4e - →O2+4OH - .

[0028] The cathode reaction zone 6 is provided with a porous carbon material 8, the surface area of which is not less than 3 square meters per gram, and the porous carbon material 8 is connected to the negative electrode of an external direct current power supply, so that raw water containing hexavalent chromium enters the anode reaction zone 1 and the cathode reaction zone 6 through the water inlet 3 at the same time, the raw water containing hexavalent chromium passes through the porous carbon material 8 from the lower part to the upper part, and 70% to 90% of the hexavalent chromium in the raw water passing through the porous carbon material 8 is reduced to trivalent chromium.

[0029] The surface reaction of the electrode of the porous carbon material 8 in the cathode reaction zone 6 is as follows:

[0030] Cr2O7 2- +14H + +6e - →2Cr 3+ +7H2O

[0031] HCrO 4- +4H + +3e - →Cr 3+ +4H2O

[0032] 2H2O+2e- → H2 + 2H2O -

[0033] The above formula can be simplified as:

[0034] Cr 6+ + 3e - → Cr 3+

[0035] 2H + + e - → H2

[0036] The cathode reaction zone 6 is provided with a first water outlet 7 above the porous carbon material 8, the first water outlet 7 is communicated with the buffer zone 9, and the raw water passing through the porous carbon material 8 overflows from the first water outlet 7 into the buffer zone 9.

[0037] The bottom of the buffer zone 9 is communicated with the electric coagulation reaction zone 10 through a second water outlet 12, and an iron electrode plate array 11 is suspended in the electric coagulation reaction zone 10. The number of electrode plates of the iron electrode plate array 11 is not less than three, and the two electrode plates at the two ends are respectively connected to the positive electrode and the negative electrode of the direct current power supply. The distance between the electrode plates should be within 5-15 mm. The raw water passes upwards through the iron electrode plate array 11, and the remaining hexavalent chromium in the water is completely reduced to trivalent chromium in the electric flocculation reaction zone 10.

[0038] A third water outlet 13 is arranged in the middle of the electric coagulation reaction zone 10, and the third water outlet 13 is communicated with the inclined pipe sedimentation zone 14. An inclined pipe 16 is suspended in the inclined pipe sedimentation zone 14. A plurality of hoppers 17 are arranged at the bottom of the inclined pipe sedimentation zone 14, and a sludge discharge port 18 is arranged at the bottom of the hopper 17. A fourth water outlet 15 is arranged at the upper portion of the inclined pipe sedimentation zone 14.

[0039] All the trivalent chromium becomes chromium hydroxide flocculation, which overflows from above the iron electrode plate array 11 and enters the inclined pipe sedimentation zone 14 through the third water outlet 13, and completes the solid-liquid separation in the inclined pipe 16. The clear liquid overflows from the fourth water outlet 15 at the top, and the chromium hydroxide and the iron hydroxide solids are deposited and gathered in the hopper 17, and finally discharged through the sludge discharge port 18.

[0040] The positive electrode reaction of the iron electrode plate array 11 in the electric coagulation reaction zone 10 is as follows:

[0041] Fe-2e - → Fe 2+

[0042] Cr 6+ + 3Fe 2+ → Cr 3+ + 3Fe 3+

[0043] 2H2O + 2e - → H2 + 2H2O -

[0044] Cr 3+ +3OH - → Cr(OH)3

[0045] Fe 3+ +3OH - → Fe(OH)3

[0046] The negative reaction of the iron electrode plate array 11 in the electrocoagulation reaction zone 10 is as follows:

[0047] Cr 6+ +3e - → Cr 3+

[0048] 4H2O-4e - → O2+4OH -

[0049] Cr 3+ +3OH - → Cr(OH)3

[0050] Fe 3+ +3OH - → Fe(OH)3

[0051] Using carbon particle fillers, graphite particles of 1-10 mesh size, treating raw water of a certain stainless steel factory, the carbon particle fillers are taken out after being soaked in a high concentration of hexavalent chromium solution, after excluding the possibility of surface adsorption, a voltage of 40-100V is applied, and a current of 1-2.5A is used for testing, and the data is shown in the following table:

[0052]

[0053] Working principle: raw water containing hexavalent chromium enters the anode reaction zone 1 and the cathode reaction zone 6 through the water inlet 3, the raw water containing hexavalent chromium passes through the porous carbon material 8 upwards, part of the raw water containing hexavalent chromium is reduced to trivalent chromium, and overflows into the buffer zone 9 through the first water outlet 7, and then enters the electrocoagulation reaction zone 10 through the second water outlet 12, the raw water passes through the iron electrode plate array 11 upwards, all the raw water containing hexavalent chromium is reduced to trivalent chromium, and flows into the inclined pipe sedimentation zone 14 through the third water outlet 13, and completes solid-liquid separation in the inclined pipe 16, the clear liquid overflows from the upper fourth water outlet 15, and the chromium hydroxide and iron hydroxide solids are precipitated and accumulated in the hopper 17, and finally discharged through the sludge outlet 18;

[0054] Only electricity and a small amount of iron elements are needed to remove hexavalent chromium ions in water, greatly reducing the use of reducing agent chemicals and acid and alkali reagents in traditional process treatment of hexavalent chromium, and the salt content of the effluent is much lower than that of the traditional treatment process.

[0055] Those aspects of the description which are not otherwise fully described are deemed to be part of the prior art to those of ordinary skill in the art.

[0056] While embodiments of the present application have been shown and described, it is to be understood that various other modifications can be made by those skilled in the art without departing from the spirit and scope of the present application, which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for treating wastewater containing hexavalent chromium ions, characterized by, It comprises an anode reaction zone (1), a cathode reaction zone (6), a buffer zone (9), an electric coagulation reaction zone (10) and an inclined pipe precipitation zone (14) connected in sequence. A hanging partition is arranged between the anode reaction zone (1) and the cathode reaction zone (6), and a graphite plate array (2) is arranged in the anode reaction zone (1), at least one graphite plate anode arranged parallel to the side wall is connected to the positive pole of an external direct current power supply; A porous carbon material (8) is arranged in the cathode reaction zone (6) and connected to the negative pole of the external direct current power supply; A first water outlet (7) is arranged above the porous carbon material (8) in the cathode reaction zone (6) and connected to the buffer zone (9); The buffer zone (9) is connected to the electric coagulation reaction zone (10) through a second water outlet (12), and an iron plate array (11) is suspended in the electric coagulation reaction zone (10); A third water outlet (13) is arranged in the middle of the electric coagulation reaction zone (10) and connected to the inclined pipe precipitation zone (14), an inclined pipe (16) is suspended in the inclined pipe precipitation zone (14), a plurality of hoppers (17) are arranged at the bottom of the inclined pipe precipitation zone (14), a sludge discharge port (18) is arranged at the bottom of each hopper (17), and a fourth water outlet (15) is arranged at the upper part of the inclined pipe precipitation zone (14).

2. The apparatus for treating wastewater containing hexavalent chromium ions according to claim 1, wherein The anode reaction zone (1), the cathode reaction zone (6), the buffer zone (9), the electric coagulation reaction zone (10) and the inclined pipe precipitation zone (14) are integrally connected through a box.

3. The apparatus for treating wastewater containing hexavalent chromium ions according to claim 1, wherein The anode reaction zone (1) is provided with a water inlet (3), an exhaust valve (4) and a gas pressure gauge (5).

4. The apparatus for treating wastewater containing hexavalent chromium ions according to claim 1, wherein The porous carbon material (8) is connected to the negative pole of the external direct current power supply.

5. The apparatus for treating wastewater containing hexavalent chromium ions according to claim 1, wherein The number of the iron plate array (11) is not less than three, and the two end plates are respectively connected to the positive pole and the negative pole of the direct current power supply, and the distance between the plates is within 5-15 mm.

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