Electrochemical treatment system

Abstract

The utility model discloses an electrochemical treatment system, which comprises a container filled with electrolyte. The cathode is placed in the container; the anode is placed in the container; the power supply is respectively connected with the anode and the cathode through wires; the active region of the anode is coated with a filler layer; the utility model has the innovation points that the anode is wrapped with the filler layer, so that hydrogen ions produced by the anode react with the material of the filler layer to the greatest extent, the neutralization effect of H < + > on OH <-> produced by the cathode is further relieved, the efficiency of an electrochemical induced precipitation technology is greatly improved, the energy consumption is remarkably reduced, and the regulation and control of the precipitation position of a product are facilitated.

Description

Technical Field

[0001] The utility model relates to the field of sewage treatment, and specifically relates to an electrochemical treatment system. Background Technique

[0002] Phosphorus resources are non-renewable and irreplaceable. Against the backdrop of current tight supply and strong demand, its global reserves are decreasing sharply, and the price is gradually rising. The removal and recovery of nitrogen and phosphorus in sewage are of great significance for solving potential resource shortage crises, protecting water environment, and ensuring food production. The electrochemical induced precipitation technology has the advantages of not requiring the addition of chemical reagents and automation, and is a type of new sewage treatment and resource recovery technology with great potential. Currently, optimizing the electrochemical induced precipitation technology is of great significance for promoting its development in the field of sewage resource recovery. The core principle of the electrochemical induced precipitation technology in in-situ sewage treatment lies in that water molecules undergo a reduction reaction to generate OH - , forming a high pH region near the cathode to induce the precipitation of phosphates (such as iron phosphate, aluminum phosphate, and magnesium ammonium phosphate, etc.), and realizing the precipitation and recovery of ammonia nitrogen and phosphate radicals at the cathode.

[0003] In this technology, in addition to the reduction reaction occurring at the cathode to generate OH - , an oxidation reaction occurs at the anode simultaneously to generate H + . In the current membrane-free integrated system, H + combines with OH - to regenerate H2O, resulting in low utilization rate of OH - ; to solve the problem of low utilization rate of OH - , it can be solved by introducing an ion exchange membrane, but introducing redundant membrane device components and their high maintenance costs undoubtedly bring many obstacles to the large-scale promotion and application of this technology.

[0004] To solve the problem of introducing redundant membrane device components and their high maintenance costs, the applicant proposed a technical solution with the patent number ZL202210353909.X. This technology can solve the above problems and has low cost. However, in the actual use process, the barrier in this patented technical solution is the anode, and only part of the anode contacts the filler, and there will still be some hydrogen ions that do not pass through the filler and consume hydroxide ions through a neutralization reaction. Content of the Utility Model

[0005] Therefore, to solve the above deficiencies, the utility model provides an electrochemical treatment system herein. The innovation point of the utility model compared with the invention patent with the patent number ZL202210353909.X is that a filler layer is wrapped around the anode, maximizing the reaction of hydrogen ions generated by the anode with the material of the filler layer, and further alleviating the impact of H + on OH generated by the cathode- Its neutralization effect significantly improves the efficiency of the electrochemically induced precipitation technology, significantly reduces energy consumption, and helps to control the precipitation position of the product.

[0006] Specifically, an electrochemical treatment system includes

[0007] a container filled with an electrolyte solution;

[0008] a cathode placed in the container;

[0009] an anode placed in the container; and

[0010] a power supply connected to the anode and the cathode respectively through wires;

[0011] The working area of the anode is wrapped with a filler layer that can react with hydrogen ions.

[0012] Optionally, the filler layer is formed by filling fillers around the working area of the anode, and a mesh barrier is provided in the container to prevent the fillers from moving towards the cathode and keep the fillers wrapped around the working area of the anode.

[0013] Optionally, the mesh barrier is in a columnar shape sleeved around the anode, and there is a gap for filling fillers between the inner wall of the mesh barrier and the outer wall of the anode.

[0014] Optionally, the cathode is in a cylindrical shape and has through holes on its outer wall;

[0015] The cylindrical cathode is sleeved around the mesh barrier, and there is a gap between the outer wall of the mesh barrier and the inner wall of the cathode.

[0016] Optionally, the mesh barrier is in a sheet shape and divides the container into a cathode area and an anode area;

[0017] Fillers that wrap the working area of the anode are filled in the anode area to form a filler layer that wraps the anode.

[0018] Optionally, this electrochemical treatment system is used for sewage treatment, the electrolyte solution is an aqueous liquid, and the filler layer and the fillers are materials that can react with hydrogen ions and release corresponding metal cations and anions.

[0019] The utility model has the following advantages:

[0020] The design key point of the utility model is to wrap a filler layer around the anode. Since the anode is completely wrapped by the filler, the hydrogen ions generated by the anode must pass through the filler during the diffusion process to the solution, ensuring the maximum reaction between the hydrogen ions and the filler. The reaction between the hydrogen ions and the filler can be further enhanced, so that the release of cations and OH -The accumulation is also more obvious than before. Compared with the prior art, it further alleviates H + The neutralization effect on OH produced by the cathode - significantly improves the efficiency of the electrochemically induced precipitation technology, significantly reduces energy consumption, and helps to control the precipitation position of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the present utility model;

[0022] Figure 2 is an overall structural diagram of the present utility model when the mesh barrier is columnar;

[0023] Figure 3 is Figure 2 a structural diagram of the state (split state);

[0024] Figure 4 is Figure 2 a structural diagram of the state with the container removed (split state);

[0025] Figure 5 is a structural diagram of the mesh barrier in columnar form connected to the container cover;

[0026] Figure 6 is a structural diagram of the cathode in cylindrical form;

[0027] Figure 7 is an overall structural diagram of the present utility model when the mesh barrier is sheet-like;

[0028] Figure 8 is a schematic diagram of calcium release;

[0029] Figure 9 is a schematic diagram of the change in system pH;

[0030] Figure 10 is a schematic diagram of phosphorus removal efficiency;

[0031] Figure 11 is a schematic diagram of the energy consumption of the electrochemical treatment system;

[0032] Figure 12 is a schematic diagram of the tendency of phosphorus to precipitate calcium phosphate;

[0033] In the figure: 1. Power supply; 2. Anode; 3. Mesh barrier; 4. Filler; 5. Cathode; 6. Electrolyte; 7. Container; 8. Filler layer; 9. Container cover. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0035] In this context, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0036] As described in the background art, in the technical solution with the patent number ZL202210353909.X, since the barrier is the anode, during actual use, only part of the anode contacts the filler, and there are still some hydrogen ions that do not pass through the filler and consume hydroxide ions through the neutralization reaction.

[0037] For the above reasons, as Figure 1 shown, the present embodiment provides an electrochemical treatment system, including

[0038] a container 7 filled with an electrolyte;

[0039] a cathode 5 placed in the container;

[0040] an anode 2 placed in the container; and

[0041] a power supply 1 connected to the anode and the cathode respectively through wires;

[0042] The active area of the anode 5 is wrapped with a filler layer 8, and the active area of the anode is the effective part of the anode inserted into the electrolyte to participate in electrolysis.

[0043] When the above technical solution is in use, a circuit is formed between the cathode and the anode in the electrolyte. When the circuit is closed, an oxidation reaction of water molecules occurs on the surface of the anode, generating hydrogen ions and oxygen. Some of the hydrogen ions are neutralized by the filler layer, and the materials in the filler layer are acid hydrolyzed and release the cations required for precipitation. For example, when oyster shell fragments (mainly composed of calcium carbonate) are selected as the material of the filler layer, some of the generated hydrogen ions will be neutralized and consumed by the oyster shell fragments, releasing calcium ions and alleviating the depletion of hydrogen ions on hydroxide ions, and the pH of the system increases; in the above technical solution, the anode is completely wrapped by the filler layer, and the hydrogen ions generated by the anode must pass through the materials in the filler layer during the diffusion process to the solution, ensuring the maximum reaction between hydrogen ions and the filler. By improving the anode wrapped with the filler layer in the present invention, the reaction between hydrogen ions and the materials in the filler layer can be further enhanced, and the release of cations and the accumulation of OH - become more obvious than before.

[0044] Exemplarily, the anode material is selected as titanium metal loaded with rubidium and iridium on the surface. The anode material can be common inert metals and carbon materials in the art, or even modified materials, etc., to meet the requirement of the anode for oxidizing water molecules to generate hydrogen ions; the cathode material can be common metals and carbon materials in the art, or even modified materials, etc., to meet the requirement of the cathode for reducing water molecules to generate hydroxide ions.

[0045] In order to form a stable filler layer on the anode, in one embodiment, as Figures 2 - 6 shown, the filler layer 8 is formed by filling the filler 4 around the anode action area. A mesh barrier 3 is provided in the container to prevent the filler from moving towards the cathode and keep the filler wrapped around the anode action area. A stable space is formed around the anode by the mesh barrier, and the filler is filled in this space, thereby realizing the wrapping of the anode by the filler. By this technical means, the reaction area between H + at the anode and the filler can be increased, alleviating the depletion of hydrogen ions on hydroxide ions; and the filler is also more stable.

[0046] Exemplarily, the filled filler can be any natural or artificial product that can react with hydrogen ions and release the corresponding metal cations and anions.

[0047] In one embodiment, as Figures 2 - 6 shown, the mesh barrier 3 is in a columnar shape (as Figure 5 shown) sleeved on the periphery of the anode, and there is a gap for filling the filler between the inner wall of the mesh barrier and the outer wall of the anode.

[0048] As Figure 6 shown, the cathode 5 is in a cylindrical shape and has through holes on the outer wall;

[0049] The cylindrical cathode is sleeved on the mesh barrier. There is a gap between the outer wall of the mesh barrier and the inner wall of the cathode. During assembly, it is installed in the container through the container cover plate 9.

[0050] In this embodiment, as Figures 2 - 4 shown, the rod-shaped anode is placed inside the space formed by the mesh barrier. The anode and the mesh barrier are concentric circles with the cathode inside and outside. Both are jointly fixed in an electrolytic cell of appropriate size. The direct current provided by an external DC power supply is supplied to the system through the aforementioned anode and cathode conducting rods, forming a closed loop together with the electrolyte.

[0051] In one embodiment, another formation method of the filler layer is provided. As Figure 7 shown, the mesh barrier 3 is sheet-shaped and divides the container into a cathode area and an anode area; in the anode area, a filler that wraps the anode action area is filled to form a filler layer that wraps the anode.

[0052] In another embodiment, the electrochemical treatment system is used for sewage treatment to achieve phosphorus recovery; during use, an appropriate amount of oyster shell fragments are used as the filler and filled into the mesh barrier. The anode is wrapped by the oyster shell fragments and jointly fixed in the electrolytic cell with the cathode. 10 mM Na2SO4 and 1 mM P solution are selected as the simulated wastewater, and under the condition of providing an external power supply (applying a current value of 20 mA), it is treated for 4 hours (experimental group 1). In addition, the electrochemical treatment system with a net-bag-shaped anode in the solution described in the patent application with the patent number ZL202210353909.X applied by the applicant is also used for phosphorus recovery with the same operating parameters and serves as a control group here (experimental group 2). The calcium ion release, pH value change, phosphorus removal efficiency, unit energy consumption, and precipitation position of the electrochemical treatment system described in the present utility model are as Figures 8 - 12 shown.

[0053] It can be seen from the results of experimental group 1 that some hydrogen ions are neutralized by the oyster shell fragments, alleviating the depletion of hydroxide ions, and the concentration of hydroxide ions in the area outside the mesh barrier increases (as Figure 9 shown). At the same time, calcium carbonate is acidolyzed by hydrogen ions, and the calcium ion concentration in the system also increases accordingly (as Figure 8 shown). On this basis, calcium phosphate is induced to precipitate in the system, thus achieving phosphorus recovery.

[0054] By comparing the results of experimental group 1 and experimental group 2, it can be seen that the optimization of the structure of the electrochemical system described in the present utility model greatly promotes the reaction between hydrogen ions and oyster shell fragments, making the release of calcium ions and the accumulation of hydroxide ions in the system of experimental group 1 exceed those of experimental group 2, manifested as the calcium ion concentration and pH value of the system in experimental group 1 being higher than those in experimental group 2 (as Figure 8 andFigure 9 as shown). On the contrary, in Experimental Group 2, the traditional mesh-shaped anode functions as a barrier. Only part of the anode is in contact with the filler, and there are still some hydrogen ions that do not pass through the filler and pass through H + -OH - neutralization reaction consumes hydroxide ions, showing that the calcium ion concentration and pH value of the system are lower than those in Experimental Group 1 (as Figure 8 and Figure 9 shown). Therefore, the calcium phosphate saturation index in the system of Experimental Group 1 is significantly increased, ultimately improving the electrochemical induction of calcium phosphate precipitation, that is, the efficiency of phosphorus removal, which is consistent with the comparison results of the phosphorus removal efficiency between Experimental Group 1 and Experimental Group 2 (as Figure 10 shown). On this basis, the utility model system has a higher phosphorus removal efficiency per unit time. Although the voltage is relatively high, the unit energy consumption is significantly reduced, which is reflected as the unit energy consumption of Experimental Group 1 being lower than that of Experimental Group 2 (as Figure 11 shown). In addition, since the pH of the system in Experimental Group 1 is significantly higher than that in Experimental Group 2, calcium phosphate tends to precipitate homogeneously in the solution (as Figure 12 shown) rather than on the cathode surface, thus alleviating problems such as cathode scaling and electrode passivation caused by it.

[0055] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electrochemical treatment system, comprising a container filled with an electrolyte; a cathode placed in the container; an anode placed in the container; and a power source connected to the anode and the cathode respectively through wires; characterized in that: the working area of the anode is wrapped with a packing layer that can react with hydrogen ions; the packing layer is formed by packing materials filled around the working area of the anode, and a mesh barrier is provided in the container to prevent the packing from moving towards the cathode and keep the packing wrapped around the working area of the anode.

2. The electrochemical treatment system according to claim 1, wherein: The mesh barrier is columnar and sleeved around the anode, and there is a gap for packing materials between the inner wall of the mesh barrier and the outer wall of the anode.

3. An electrochemical treatment system according to claim 2, characterized in that: The cathode is cylindrical and has through holes on its outer wall; the cylindrical cathode is sleeved on the mesh barrier, and there is a gap between the outer wall of the mesh barrier and the inner wall of the cathode.

4. An electrochemical treatment system according to claim 1, wherein: The mesh barrier is sheet-shaped and divides the container into a cathode area and an anode area; in the anode area, packing materials that wrap the working area of the anode are filled to form a packing layer wrapped around the anode.

5. An electrochemical treatment system according to any one of claims 1-4, characterized in that: This electrochemical treatment system is used for sewage treatment. The electrolyte is an aqueous liquid, and the packing layer and the packing are materials that can react with hydrogen ions and release corresponding metal cations and anions.

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