Three-dimensional electrode electrochemical wastewater treatment small-scale test device

Abstract

The utility model relates to a three-dimensional electrode electrochemical wastewater treatment small-scale test device which comprises a baffled reactor, a peristaltic pump, four polar plates, a particle electrode, a direct-current power supply, a lead for connecting the direct-current power supply and the polar plates, and a filling lattice basket for containing the particle electrode, the particle electrode is a plurality of recycled aluminum tank particles which are formed by cutting and bending a recycled aluminum tank and have the size of one cubic centimeter, and surface oxidation films of the recycled aluminum tank particles are cleaned by hydrochloric acid. The recycling aluminum pot particles serving as the particle electrode are easy and convenient to manufacture and low in cost; pollutants are easy to clean and recycle after being attached to the particle electrode; the filling basket can prevent short-circuit current caused by contact between the particle electrode and the polar plate; the treatment effect of the recycled aluminum tank particles as the particle electrode on the nanofiltration concentrated solution is obviously better than that of particle electrodes made of other materials.

Description

Technical Field

[0001] The utility model relates to the technical field of three-dimensional electrode electrochemical wastewater treatment, in particular to a small-scale test device for three-dimensional electrode electrochemical wastewater treatment. Background Art

[0002] Three-dimensional electrode electrochemical technology has been applied by many domestic and foreign scholars in the field of wastewater treatment. At present, most studies use granular activated carbon as the particle electrode. Granular activated carbon (GAC) is the most widely used particle electrode. The surface of activated carbon contains a large number of functional groups and a unique pore structure, which makes it have good adsorption performance. In addition, under the action of the electric field, activated carbon particles can undergo a reduction reaction on the inductive cathode side to convert O2 into H2O2. On the other hand, activated carbon can also catalyze the decomposition of H2O2 to produce -OH to further remove pollutants in the water. However, its electrocatalytic activity is not high enough, which can easily lead to pore blockage and reduce the degradation efficiency. After multiple runs, a large number of intermediate products will be enriched into a dense pollution layer covering the surface of the activated carbon, hindering the electrocatalytic reaction and resulting in poor treatment effect.

[0003] In order to improve the ability of the three-dimensional system to treat wastewater, some researchers directly filled metal catalysts into the three-dimensional reaction device to cause the Fenton reaction in the reaction device, which can increase the -OH yield. Although the filling of metals or metal oxides improves the treatment effect of the three-dimensional electrode system, there are phenomena such as catalyst loss and large consumption of particle electrodes during the reaction process, which leads to increased costs; and the intermediate products attached to the surface of the particle electrode are difficult to clean, and the particle electrode is not easy to be recycled and reused. Utility Model Content

[0004] In order to overcome the above-mentioned defects, it would be advantageous for the utility model to provide a three-dimensional electrode electrochemical wastewater treatment pilot device with extremely low cost and excellent effect.

[0005] To this end, the utility model provides a three-dimensional electrode electrochemical wastewater treatment pilot device, including a baffled reactor, a peristaltic pump, four plates, a particle electrode, a DC power supply, and wires connecting the DC power supply and the plates, wherein the utility model also includes a filling grid basket for containing the particle electrode, wherein the particle electrode is a plurality of recycled aluminum can particles of one cubic centimeter in size which are cut and bent from recycled aluminum cans and whose surface oxide film has been cleaned with hydrochloric acid.

[0006] Furthermore, the filling grid basket is a frame basket made of a mesh sheet of PE material and having an opening on the top.

[0007] Furthermore, the thickness of the mesh sheet is set to 1.6 mm, and the mesh holes of the mesh sheet are set to 4 mm*4 mm.

[0008] Furthermore, when the effective volume of the baffled reactor is set to 2.0 L, the thickness of the filling grid is set to 1.0 to 2.5 cm, and the filling volume of the recycled aluminum can particles in the filling grid is 378 to 945 cm 3 The thickness of the filling grid is preferably 1.0 cm, and the filling volume of the recycled aluminum can particles in the filling grid is 378 cm 3 .

[0009] Furthermore, the filling basket is placed on the bottom surface of the baffled reactor and clamped between two adjacent plates along the thickness direction; the plate is fixed in the groove at the bottom of the baffled reactor, and the groove width is 5mm, which is exactly equal to the thickness of the plate.

[0010] Furthermore, the peristaltic pumps are respectively connected to the water inlet and the water outlet of the baffled reactor.

[0011] Furthermore, the four electrodes are connected in a single-pole parallel connection of anode-cathode-anode-cathode.

[0012] Still further, the hydrochloric acid is 10% hydrochloric acid.

[0013] The utility model has the following advantages: 1) the recycled aluminum can particles used as particle electrodes are easy to make and have extremely low cost; 2) since the recycled aluminum can particles are one cubic centimeter in size, that is, the particles are relatively large, they are easy to clean and recycle after the pollutants are attached; 3) the use of a filling grid basket to hold the recycled aluminum can particles can prevent the particle electrode from contacting the electrode plate, thereby avoiding short-circuit current; 4) the recycled aluminum can particles are used as particle electrodes, and because of their bending and folding, which makes them have a large specific surface area and are not easy to adhere, the treatment effect on nanofiltration concentrate is significantly better than that of particle electrodes made of other materials, that is, they have better organic matter removal rate and chromaticity removal rate, etc., and reduce energy consumption.

[0014] These and other aspects of the present invention will be more clearly explained by referring to the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The structure and further objects and advantages of the present invention will be better understood through the following description in conjunction with the accompanying drawings, in which the same reference numerals identify the same elements:

[0016] Figure 1 It is a structural schematic diagram of a small-scale test device for electrochemical wastewater treatment of a three-dimensional electrode according to a specific embodiment of the utility model;

[0017] Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure of a filling grid basket of a small-scale test device for three-dimensional electrode electrochemical wastewater treatment is shown;

[0018] Figure 3 yes Figure 1 The comparison chart of the chromaticity removal rate change of the three-dimensional electrode electrochemical wastewater treatment pilot device when the particle electrode material (ACP = recycled aluminum can particles, AP = metal aluminum particles, GAC = activated carbon particles) is changed;

[0019] Figure 4 yes Figure 1 The following is a comparison chart of COD removal rate changes of a three-dimensional electrode electrochemical wastewater treatment pilot device when the particle electrode material (ACP = recycled aluminum can particles, AP = metal aluminum particles, GAC = activated carbon particles) is changed;

[0020] Figure 5 yes Figure 1 The comparison chart of TOC removal rate changes of the three-dimensional electrode electrochemical wastewater treatment pilot device when the particle electrode material (ACP = recycled aluminum can particles, AP = metal aluminum particles, GAC = activated carbon particles) is shown;

[0021] Figure 6 yes Figure 1 The energy consumption (kWh / kgCOD) comparison chart of the three-dimensional electrode electrochemical wastewater treatment pilot device when the particle electrode material (ACP = recycled aluminum can particles, AP = metal aluminum particles, GAC = activated carbon particles) is changed;

[0022] Figure 7 yes Figure 1 The comparison chart of chromaticity removal rate of the three-dimensional electrode electrochemical wastewater treatment pilot device changing with time at different particle electrode filling volumes is shown;

[0023] Figure 8 yes Figure 1 The comparison chart of COD removal rate of the three-dimensional electrode electrochemical wastewater treatment pilot device changing with time at different particle electrode filling volumes is shown;

[0024] Fig. 9 yes Figure 1 The TOC removal rate comparison chart of the three-dimensional electrode electrochemical wastewater treatment pilot device with different particle electrode filling volumes over time;

[0025] Fig.10 yes Figure 1 The energy consumption (kWh / kgCOD) comparison chart of the three-dimensional electrode electrochemical wastewater treatment pilot device at different particle electrode filling volumes;

[0026] Fig.11 yes Figure 1 The sludge volume (mL) of the three-dimensional electrode electrochemical wastewater treatment pilot device at different particle electrode filling volumes is shown. DETAILED DESCRIPTION

[0027] The specific implementation of the present utility model will be described below in conjunction with the accompanying drawings.

[0028] First, before describing the specific implementation methods in this article, the following concepts are explained to make the concepts mentioned in this article clearer.

[0029] Electrochemistry: It is the science of studying the charged interface phenomenon formed by two types of conductors and the changes that occur on it. As an environmentally friendly advanced oxidation technology, it is more and more widely used in water treatment due to its simple equipment, easy operation, high efficiency, no need for additional reagents, and the increase in electricity utilization rate brought about by the diversification of electricity sources. The removal of pollutants in water bodies mainly includes direct oxidation and indirect oxidation at the anode. Direct oxidation refers to the diffusion of organic pollutants from the main body of the electrolyte to the surface of the anode, and then direct oxidation and degradation on the surface of the anode plate. The organic pollutants are oxidized and broken, the molecular weight is reduced, and even mineralized in the end, thereby achieving the purpose of removing pollutants from the water body.

[0030] Three-dimensional electrode electrochemistry: Three-dimensional electrode electrochemistry optimizes the performance based on traditional two-dimensional electrode electrochemistry. Granular materials are added between the anode and cathode as particle electrodes to construct a three-dimensional system, which greatly improves the current efficiency and enhances the removal effect of organic pollutants.

[0031] Nanofiltration concentrate: Nanofiltration is a technology that uses pressure difference as a driving force to separate substances with smaller molecular weight from solvents. The process used in landfills is pretreatment-A 2 O Biochemical treatment (anaerobic-anoxic-aerobic) - nanofiltration / reverse osmosis, in which the part of the solution retained by nanofiltration is called nanofiltration concentrate.

[0032] -OH: Hydroxyl radical

[0033] Energy consumption analysis: mainly refers to the electrical energy consumed in the process of treating nanofiltration concentrate by the three-dimensional electrochemical system, which is calculated according to the following formula: E = 1000UIt / (COD t -COD0) / V

[0034] Where: E — Specific energy consumption (kWh / kgCOD);

[0035] U — Voltage during the reaction, in v;

[0036] I — The current during the reaction, in A;

[0037] T — reaction time, in h;

[0038] V — Volume of nanofiltration concentrate in the reactor (L);

[0039] COD 0—initial COD value (mg / L);

[0040] COD t —Effluent COD value (mg / L).

[0041] Recycled aluminum cans: refers to recycled aluminum cans.

[0042] refer to Figure 1 to Figure 2 , the three-dimensional electrode electrochemical wastewater treatment pilot device of this embodiment is introduced. In this embodiment, the three-dimensional electrode electrochemical wastewater treatment pilot device includes a baffled reactor 1, a peristaltic pump 2, four plates 3, a particle electrode 4, a DC power supply 5, and a wire 6 connecting the DC power supply 5 and the plate 3, and also includes a filling grid basket 7 for holding the particle electrode 4. The particle electrode 4 is a number of recycled aluminum can particles 40 of one cubic centimeter in size, which are cut and bent from recycled aluminum cans and the surface oxide film of which has been cleaned with hydrochloric acid.

[0043] Specifically, in this embodiment, the collected recycled aluminum cans are cut, bent and folded into aluminum blocks of one cubic centimeter in size, and then the surface oxide film is washed off with 10% hydrochloric acid to form recycled aluminum can particles 40. It should be noted that the bending and folding is to allow the particle electrodes to have a larger surface area under the same volume, and after filling, the reaction space between the particle electrodes will become larger, and no adhesion will occur, which can speed up the electrode reaction rate and improve the treatment effect.

[0044] like Figure 1 and Figure 2 As shown, the filling grid basket 7 is a frame basket made of a mesh sheet 70 of PE material and having an upper opening. The upper opening of the filling grid basket 7 is used to fill the recycled aluminum can particles 40 therein to serve as the particle electrode 4. Figure 2 As shown, the size of the grid holes 71 on the grid sheet 70 is set to 4mm*4mm, and the thickness of the entire grid sheet 70 is set to 1.6mm. The purpose of this setting is to prevent the recycled aluminum can particles 40 from escaping from the filling grid basket 7, thereby preventing the particle electrode 4 from contacting the electrode plate 3 and causing a short-circuit current (the conductivity of the recycled aluminum can particles 40 is much greater than the nanofiltration concentrate 8 in the baffle reactor 1. Therefore, when the electrode plate 3 and the recycled aluminum can particles 40 are in direct contact, most of the current will pass through the recycled aluminum can particles 40, causing a short circuit, thereby causing the effective current of the nanofiltration concentrate 8 to decrease, and the treatment effect is not good). Figure 1As shown, the filling basket 7 is placed on the bottom surface of the baffled reactor 1 and clamped between two adjacent pole plates 3 along the thickness direction; the pole plate 3 is fixed in a groove (not shown) at the bottom of the baffled reactor 1, and the groove width is 5 mm, which is exactly equal to the thickness of the pole plate.

[0045] It should be noted that, in this embodiment, the effective volume of the baffled reactor 1 is set to 2.0 L, the thickness a of the filling grid basket 7 (i.e., the filling thickness of the particle electrode 4) is set to 1.0 cm, and the filling volume of the recycled aluminum can particles 40 in the filling grid basket 7 is 378 cm 3， , that is, the volume of particle electrode 4 is 378 cm 3 .

[0046] Of course, the thickness of the filling grid basket 7 is in the range of 1.0 to 2.5 cm, and the filling volume of the recycled aluminum can particles 40 in the filling grid basket 7 is in the range of 378 to 945 cm 3， The effect is very good within the range. Figures 7 to 11 That is, in another embodiment, when the thickness of the filling grid basket 7 is 1.5 cm, the filling volume of the recycled aluminum can particles 40 in the filling grid basket 7 can be 567 cm 3， When the thickness of the filling grid basket 7 is 2.5cm, the filling volume of the recycled aluminum can particles 40 in the filling grid basket 7 can be 945cm 3 .

[0047] It should be understood that the effective volume of 2.0 L of the baffled reactor 1 of this embodiment means that 2.0 L of nanofiltration concentrate 8 is poured into the baffled reactor 1 after each placement of the electrode plates 3 and the particle electrodes 4 with different filling volumes.

[0048] For example Figure 1 As shown, four electrodes 3 are fixed in the baffled reactor 1, and the connection mode of the four electrodes 3 is monopolar parallel (MP-P), that is, anode-cathode-anode-cathode. The peristaltic pump 2 is respectively connected to the water inlet and outlet of the baffled reactor 1, so that the nanofiltration concentrate 8 in the baffled reactor 1 is in a flowing state, optimizing its water conditions.

[0049] Before explaining the effects of the present invention, the water quality of the nanofiltration concentrated liquid 8 in the baffled flow reactor 1 is introduced. The water quality indicators are shown in Table 1 below.

[0050] Table 1

[0051] Water quality parameters Numerical range COD (mg / L) 1189.39-1227.92 pH 6.37-6.64 TOC (mg / L) 795-805.6 Chromaticity (Pt-Co) 1105-1130

[0052] In order to compare the effect, the four plates 3 of the utility model are used to conduct experiments with four graphite plates. After direct current is passed through the baffled reactor, the nanofiltration concentrate is treated for 2 hours. Various particle electrodes are compared, specifically the performance of three-dimensional electrode electrochemistry using graphite particles, metal aluminum particles and recycled aluminum can particles as particle electrodes in terms of color removal rate, TOD removal rate, COD removal rate and energy consumption of the nanofiltration concentrate. The specific performance is shown in Figures 3 to 6 .

[0053] Figure 3 The figure shows the change of color removal rate of nanofiltration concentrate by three-dimensional electrode system under three different particle electrodes. It can be seen from the figure that most of the color substances are removed in the early stage of the reaction. The color removal rate is the lowest when the activated carbon particles (GAC in the figure) are used as particle electrodes, which is only about 60%. The reason may be that when the activated carbon particles are used as particle electrodes, the current short circuits, causing the solution temperature to rise continuously. After 120 min (minutes), the solution temperature in the reaction system is measured to be as high as 51 ° C; the color removal rate of the recycled aluminum can particles is generally higher than that of the metal aluminum particles (AP in the figure), indicating that the Al produced by the electrolysis of the recycled aluminum can particles (ACP in the figure) in the three-dimensional system 3+ High concentration;

[0054] Figure 4 and Figure 5 They respectively represent the changes in COD (chemical oxygen demand) and TOC (total organic carbon) removal rates during the three-dimensional system's treatment of nanofiltration concentrate. After 120 minutes of treatment, the COD removal rate of activated carbon particles was only 26.41%, while the COD removal rates of recycled aluminum can particles and metal aluminum particles as particle electrodes were both higher than 50%, nearly doubling the removal effect; the removal rate of recycled aluminum can particles as particle electrodes was close to 80%, and the removal rate was higher than that of the other two particle electrodes;

[0055] Figure 6 The graph shows the changes in energy consumption under three types of particle electrode materials. The energy consumption of recycled aluminum can particles is only 64.46kWh / (kg COD), which is significantly lower than the energy consumption of the other two particle electrodes.

[0056] Figures 3 to 6The experimental results show that although aluminum metal particles have a better treatment effect on nanofiltration concentrate than activated carbon particles, the treatment effect of recycled aluminum can particles is better than that of aluminum metal particles. This is mainly because after the aluminum metal particles are filled, as the electrolysis reaction proceeds, the aluminum metal particles will dissolve, and the aluminum ions react with substances such as hydroxide in the reaction system to form precipitation attached to the surface of the particle electrode. Due to the small gaps between the aluminum metal particles themselves, the aluminum metal particles stick together, resulting in a decrease in current efficiency, thus affecting the treatment effect. The gaps between the recycled aluminum can particles are large, so the treatment effect is better than that of aluminum metal particles. As an extremely low-cost particle electrode, the recycled aluminum can particles have a significantly higher removal rate for the color and organic matter concentration of the nanofiltration concentrate than the particle electrodes of the other two materials, and can effectively reduce the treatment energy consumption.

[0057] The following will refer to Figures 7 to 10 , introduces the comparison of chromaticity, TOC, COD removal rate, energy consumption and sludge volume under different recycled aluminum can particle filling amounts and blank control tests (Blank, i.e. no filling).

[0058] from Figure 7 It can be seen that in the first 20 min of the reaction, as the filling volume of the particle electrode increases, the removal rate of the colored substances in the nanofiltration concentrate by the three-dimensional electrode electrochemical system also accelerates. As the reaction time continues, the reaction gradually approaches equilibrium, and finally at a filling volume of 378 cm 3 The removal rate reached the highest 98.94% when the 3D electrode electrochemical system was used. In general, the removal rate of colored substances in the nanofiltration concentrate was relatively high.

[0059] The organic matter concentration removal rate during the reaction process is as follows: Figure 8 and Fig. 9 As shown in the figure, the results show that a larger filling volume is not more conducive to the removal of organic pollutants. The filling volume is 945cm 3 The COD removal rate was 45.81% and the filling volume was 378cm 3 and a filling volume of 567cm 3 The COD removal rates were 51.90% and 53.73%, respectively, which were better than the control group with high filling volume.

[0060] The energy consumption diagram for four different filling volumes is shown below. Fig.10 As shown in the figure, the results show that when the particle filling volume is too large or too small, the unit energy consumption of the three-dimensional particle electrode electrochemical treatment of nanofiltration concentrate will increase. This is because the filling volume is too large, causing the particle electrodes to accumulate in the limited filling space, and close contact with each other makes it easier to generate short-circuit current. Excessive recycled aluminum can particles cannot play the role of particle electrodes, resulting in a decrease in COD removal rate. Fig.10 As shown, the filling volume is 945cm3 The energy consumption is the largest when the filling volume is 378cm 3 The energy consumption is only 42.46 kWh / (kg COD). As the filling volume is further reduced to 227cm 3 , the energy consumption increases to 64.35 kWh / (kgCOD) because the filling volume is 227cm 3 The COD removal rate is low, resulting in high unit energy consumption.

[0061] It should be noted that from Figures 7 to 10 From the above, although the blank control test is not the most energy-intensive in terms of energy consumption, its final chroma removal rate, TOC removal rate and COD removal rate are not as good as those of other filling volume tests. Fig.11 There is no data from the blank control test because no sludge was produced in the blank test.

[0062] Fig.11 It shows the sludge volume produced under several different filling volumes. As the filling volume decreases, the sludge volume also decreases. The filling volume is 378 cm 3 The sludge volume is only 220 mL and the filling volume is 378 cm 3 The organic matter removal rate is also relatively high, and the energy consumption is lower than that of other filling volumes. Taking all factors into consideration, the optimal filling volume of recycled aluminum can particles is 378 cm 3 .

[0063] The technical content and technical features of the utility model have been disclosed above, but it can be understood that under the creative idea of ​​the utility model, those skilled in the art can make various changes and improvements to the above structure, including the combination of technical features disclosed or claimed separately here, and other combinations that obviously include these features. These deformations and / or combinations all fall within the technical field involved in the utility model and fall within the protection scope of the claims of the utility model.

Claims

1. A three-dimensional electrode electrochemical wastewater treatment pilot device, comprising a baffled reactor, a peristaltic pump, four plates, particle electrodes, a DC power supply, and a wire connecting the DC power supply and the plates, characterized in that It also includes a filling grid basket for containing particle electrodes. The particle electrodes are a number of recycled aluminum can particles of one cubic centimeter in size, which are cut and bent from recycled aluminum cans and have surface oxide films cleaned with hydrochloric acid.

2. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 1, characterized in that: The filling grid basket is a frame basket made of a mesh sheet of PE material and having an opening on the top.

3. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 2, characterized in that: The thickness of the mesh sheet is set to 1.6 mm, and the mesh holes of the mesh sheet are set to 4 mm*4 mm.

4. The three-dimensional electrode electrochemical wastewater treatment pilot device according to any one of claims 1 to 3, characterized in that: When the effective volume of the baffled reactor is set to 2.0 L, the thickness of the filling grid is set to 1.0 cm, and the filling volume of the recycled aluminum can particles in the filling grid is 378 cm 3 .

5. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 4, characterized in that: The filling basket is placed on the bottom surface of the baffled reactor and is clamped between two adjacent electrode plates along the thickness direction.

6. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 5, characterized in that: The peristaltic pump is respectively connected to the water inlet and the water outlet of the baffled reactor.

7. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 5, characterized in that: The connection mode of the four electrodes is a single-pole parallel connection mode of anode-cathode-anode-cathode.

8. The three-dimensional electrode electrochemical wastewater treatment pilot device according to claim 5, characterized in that: The hydrochloric acid is 10% hydrochloric acid.

Images