A Penetrating Electro-Catalytic Water Treatment Method with the Function of Controlling the Generation of Electrolysis By-Products

Abstract

A penetrating electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products, which relates to the field of water treatment technology. The present invention aims to solve the problems in traditional electrochemical advanced oxidation processes, such as the oxygen evolution side reaction caused by high anode potential, the generation of electrolytic toxic by-products, high energy consumption, and low current efficiency. The method of the present invention utilizes an anode with a low oxygen evolution potential and a cathode rich in atomic hydrogen. The O2 generated at the anode is transported to the cathode surface by water flow through convective mass transfer, and then is activated by the atomic hydrogen at the cathode to form ·OH, which is used to remove refractory organic pollutants in water. This method enables the anode to operate at a lower potential, not only changing the traditional way of generating ·OH, reducing the reaction energy consumption and increasing the current efficiency, but also having the function of controlling the generation of electrolysis by-products, avoiding the problem of secondary pollution in the process of electrochemical water treatment, and enabling it to be applied to electrochemical water treatment more efficiently, economically and sustainably.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to a penetrating electrocatalytic water treatment method with a function of controlling the generation of electrolysis by-products. Background Art

[0002] Electrochemical advanced oxidation processes (EAOPs) remove refractory organic pollutants and disinfect water bodies by generating ·OH through electrolysis of water or direct electron transfer mediation, and have the advantages of high efficiency, cleanliness, process integration, and easy automation, and can be used as the next-generation water purification technology. However, traditional EAOPs rely on inert anodes with high oxygen evolution potentials (such as doped PbO2, boron-doped diamond, and sub-oxidized titanium); and to generate sufficient active species ·OH, a relatively high anodic potential (>2.5V vs SHE) needs to be applied, which will lead to inevitable oxygen evolution (OER) side reactions and the generation of electrolysis by-products, resulting in high energy consumption and low current efficiency. These factors have hindered the full-scale application of traditional EAOPs. Therefore, the development of a green electrocatalytic oxidation system that can operate at a relatively low anodic potential has become an urgent need.

[0003] Since the theoretical potential of OER for anodic electrolysis of water is only 1.23V vs SHE, it is easier to be activated at the anode than electro-generated ·OH (2.73V vs SHE). Molecular oxygen activation (MOA) to generate reactive oxygen species (such as ·OH, O2 ·- , H2O2, and 1 O2) is a key step in heterogeneous catalytic reactions in the fields of energy conversion and environmental catalysis. Inspired by the concept of atom economy, theoretically, the O2 generated by anodic OER can be used as an ideal precursor to generate reactive oxygen through activation. In traditional electrochemical oxygen reduction systems, O2 can be reduced to H2O2 or H2O through two-electron or four-electron transfer at the cathode, and H2O2 can be used as a precursor to generate highly oxidative ·OH in advanced oxidation processes. Therefore, it is feasible to construct an integrated MOA method that relies on the O2 generated by anodic OER and then is activated by the cathode to generate ·OH, which will provide an effective way to utilize anodic OER. More importantly, this method eliminates the need for high-oxygen evolution potential anodes in traditional EAOPs and allows the application of low-oxygen evolution potential electrodes with a wider selection (such as carbon-based materials and metals and their oxides). In addition, a low anodic potential is expected to control the generation of electrolysis by-products under anodic polarization. To achieve this goal, two key issues need to be considered, namely the selectivity of cathode MOA and the oxygen supply of the anode.

[0004] Generally, it is challenging to select a highly selective cathode capable of MOA to generate ·OH. In aqueous solutions, by-product-free activators mainly contain hydrogen (H), oxygen (O), or their derivatives. Atomic hydrogen (H*) is produced in the first step of the hydrogen evolution reaction (Volmer process) and is a hydrogen species with strong reducing properties (redox potential of -2.10 V vs SHE). Previous studies have reported that H* reduces O2 to form H2O2, and further dissociates H2O2 into ·OH through electron transfer. In this regard, palladium (Pd) is considered an excellent hydrogen storage catalyst because it can not only efficiently absorb protons to generate H* at a low overpotential but also store H* through adsorption and absorption. These processes can effectively inhibit the conversion of H* to gaseous H2 (Heyrovsky or Tafel process). Therefore, Pd can serve as a medium to achieve the Pd-H*-mediated MOA pathway of anode O2→H2O2→·OH.

[0005] To achieve this goal, it is necessary to effectively transport the anode O2 to the Pd cathode surface. However, O2 has low solubility in aqueous solutions (8.1 - 8.5 mg L at 25 °C) -1 ) and a slow diffusion rate (1.96 - 2.56×10 -9 m 2 s -1 ) problems. O2 mass transfer has been considered an important step in traditional oxygen reduction. A large number of studies have shown that through-flow porous electrodes are expected to enhance mass transfer through forced convection within the membrane pores and improve the reactivity of active sites or active substances on the electrode surface. Therefore, designing a water flow-driven system based on through-flow porous electrodes is expected to enhance the mass transfer of anode O2 to the cathode surface through water flow and achieve the sustainable supply of O2. In summary, by means of a through-flow membrane electrode device under water flow-driven conditions, using a Pd cathode capable of evolving H* and an anode with a low oxygen evolution potential, the coupling and synergy of anode OER and cathode MOA can be achieved, generating ·OH at a low anode potential, improving the efficiency of wastewater treatment, controlling the generation of electrolysis by-products, and making electrocatalytic water purification more efficient, economical, and sustainable. Summary of the Invention

[0006] The object of the present invention is to solve the problems of oxygen evolution side reactions, generation of electrolysis toxic by-products, high energy consumption, and low current efficiency caused by a high anode potential in traditional electrochemical advanced oxidation processes, and provide a method for water treatment in which cathode H* mediates the activation of anode-generated O2 to generate ·OH based on the action of water flow driving.

[0007] The present invention aims to change the traditional way of directly electrolyzing to produce ·OH by operating an anodic oxygen evolution / cathodic oxygen activation (OER / MOA) permeable electrocatalytic water treatment method under low anodic potential polarization, and solve problems such as oxygen evolution side reactions, electrolysis by-products generation, high energy consumption, and low current efficiency caused by high anodic potential in traditional EAOPs. The present invention can achieve efficient removal of pollutants in water while having the function of controlling the generation of electrolysis by-products.

[0008] Principle of the solution of the present invention:

[0009] Based on the water flow-driven activation of anodic O2 by a H⁺-rich cathode to produce ·OH, the present invention. Through a large number of studies, the conversion mechanism is as follows: First, a H⁺-rich cathode (such as a Pd electrode) is used to reduce and produce H⁺ at a negative potential; at the same time, anodic O2 flows to the cathode surface along with the water flow; then, H⁺ mediates the activation to first produce *OOH, which further becomes an H2O2 intermediate, and finally generates strongly oxidizing ·OH. The main reaction equations involved are as follows:

[0010]

[0011] O2 + H⁺ → *OOH (2)

[0012] *OOH + H⁺ → H2O2 (3)

[0013] H2O2 + H⁺ → ·OH + H2O (4)

[0014] The present invention provides a permeable electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products. In the permeable electrocatalytic device involved, as Figure 1 shown, it includes: an electrochemical reaction cell 1; a H⁺-rich permeable porous cathode 2; a permeable porous anode 3 with a low oxygen evolution potential; a DC power supply; a peristaltic pump.

[0015] The OER / MOA permeable electrocatalytic water treatment method is as follows: Add an electrolyte solution to the permeable electrocatalytic device; add the pollutants to be treated to the reaction cell; use a peristaltic pump to control a certain flow rate and control the water flow direction to be from the anode to the cathode; apply a voltage between the cathode and the anode. The O2 evolved at the anode is carried by the water flow to the cathode surface through convective forced mass transfer and is further activated by cathode H⁺ to ·OH, thereby treating the pollutants; apply a cathode potential of -0.4 to -0.7 V vs SHE to ensure the generation of cathode H⁺, and apply an anode potential of 1.5 to 2.0 V vs SHE. While ensuring anode oxygen evolution, the low anode potential also controls the generation of electrolysis by-products from the source.

[0016] A through-type electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products. In the through-type electrocatalysis, the cathode used is a hydrogen-rich atom (H*); the anode is an electrode with a low oxygen evolution potential; and the flow direction of the electrolyte is controlled to flow from the anode to the cathode; the applied cathode potential is -0.4 to -0.7 V vs SHE, and the anode potential is 1.5 to 2.0 V vs SHE.

[0017] Further, the hydrogen-rich atom (H*) electrode is a Pd-containing through-type porous tubular electrode. Pd is loaded on the electrode surface, the Pd particle size is 0.1 to 1 μm, and the Pd content is 2% to 20%; the electrode pore size is micron-sized.

[0018] Further, the hydrogen-rich atom (H*) electrode is a Pd-containing through-type porous tubular electrode. The Pd cathode is prepared by cyclic voltammetry scanning electrodeposition method: Immerse the porous conductive substrate material (such as carbon felt, graphite felt, conductive ceramic, etc.) in a 50 mM NH4Cl electrolyte containing 1 to 10 mM PdCl2. The starting potential of the cyclic voltammetry scanning is 0.1 to 0.5 V vs SHE, the termination potential is -0.6 to -0.2 V vs SHE, and the scanning rate is 1 to 10 mV s -1 , and the number of scanning cycles is 5 to 30 cycles.

[0019] Further, the low oxygen evolution potential electrode is a through-type porous tubular electrode of carbon-based or metal and its oxides (such as carbon felt, ruthenium-iridium-titanium coated electrode, etc.).

[0020] Further, the electrolyte solution is sodium sulfate or sodium perchlorate solution, and the concentration is 5 mM to 500 mM.

[0021] Further, the water flow rate of the electrolyte solution is 5 mL min -1 ~60 mL min -1 , and the distance between the anode and the cathode is 0.5 to 2 cm. The mass transfer of oxygen and pollutants is enhanced by operating in the through mode.

[0022] Further, add the pollutants to be treated to the reaction pool of the through-type electrocatalytic reaction.

[0023] Further, the pollutants to be treated are organic pollutants, and the organic pollutants are phenolic pollutants.

[0024] Further, the concentration of the organic pollutants is 1 mg L -1 ~20 mg L -1 .

[0025] Further, after adding the pollutants to be treated, the electrocatalytic water treatment time is 10 min to 180 min.

[0026] The present invention has the following beneficial effects:

[0027] 1. Under the action of water flow drive, the present invention uses a rich H* electrode (such as a Pd electrode) to indirectly activate O2 generated at the anode by the strong reducibility of H* to generate ·OH, realizing the coupling and synergy of anodic OER and cathodic MOA for treating refractory organic pollutants in water. It effectively utilizes the anodic O2 without adding additional oxidants, reducing the investment cost, and has a simple operation, facilitating large-scale application.

[0028] 2. The present invention overcomes the problem of traditional EAOPs relying on inert anodes with a high oxygen evolution potential. Since the electrode range for OER is relatively wide, the selection of anode materials for this OER / MOA through-flow electrocatalytic water treatment method is more flexible.

[0029] 3. The OER / MOA through-flow electrocatalytic water treatment method of the present invention changes the traditional way of generating ·OH, can operate at a low anodic potential polarization, reduces the reaction energy consumption, improves the current efficiency, and the generated ·OH can oxidize and degrade organic pollutants in the wastewater without selectivity, having excellent electrochemical decontamination performance.

[0030] 4. The low anodic potential of the present invention can control the generation of electrolytic toxic by-products from the source of anodic polarization, avoiding the problem of secondary pollution during the electrochemical water treatment process, making the electrocatalytic water purification more efficient, more economical, and more sustainable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the device for the constructed OER / MOA through-flow electrocatalytic water treatment method;

[0032] Figure 2 Scanning electron microscope image (SEM) of the Pd / CFF electrode;

[0033] Figure 3 Elemental and structural analysis of the Pd / CFF electrode; among them, (a) is the Pd 3d graph of X-ray photoelectron spectroscopy (XPS), and (b) is the X-ray diffraction (XRD) graph;

[0034] Figure 4 Feasibility verification of the generation of H* on the surface of the Pd / CFF electrode and H*-mediated MOA; among them, (a) is the cyclic voltammogram (CV) in a deoxygenated atmosphere, the starting potential is -1.2 to -0.8 V, the fixed termination potential is 0.8 V, and the scanning speed is 10 mV s -1 , (b) is the electron paramagnetic resonance spectrum (ESR) at a potential of -0.7 V vs SHE in a deoxygenated atmosphere, and (c) is the ESR in an oxygenated atmosphere;

[0035] Figure 5The important roles of H* production at the cathode and oxygen supply at the anode in the OER / MOA penetrating electrocatalytic water treatment method; among them, (a) shows the removal efficiency and rate constant of 2,4-DCP with a Pd-containing Pd / CFF cathode and a Pd-free CFF cathode at different cathode potentials, (b) shows the rate constant of 2,4-DCP removal with different anode materials, and (c) shows the rate constant of removal in different water flow directions (AC is the direction from the anode to the cathode, and CA is the direction from the cathode to the anode);

[0036] Figure 6 The decontamination performance of the OER / MOA penetrating electrocatalytic water treatment method at different flow rates; among them, (a) shows the ·OH concentration at different flow rates when the cathode potential is -0.5 V vs SHE, (b) shows the corresponding removal efficiency and rate constant of 2,4-DCP, and (b) shows the corresponding energy consumption and current efficiency;

[0037] Figure 7 The performance comparison test between the OER / MOA penetrating electrocatalytic water treatment method and traditional EAOPs; among them, (a) shows the current efficiency when the removal rate is comparable (~95%), (b) shows the energy consumption, and (c) shows the generation of chlorination by-products;

[0038] Figure 8 The stability and adaptability test of the OER / MOA penetrating electrocatalytic water treatment method; among them, (a) shows the decontamination test for 10 consecutive cycles, and (b) shows the removal efficiency of 2,4-DCP in actual water quality (tap water and river water). Detailed implementation mode

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer and more understandable, the spirit of the content disclosed in the present invention will be described in detail below. After any person skilled in the relevant technical field understands the embodiments of the content of the present invention, they can make changes and modifications based on the technology taught by the content of the present invention, which does not deviate from the spirit and scope of the content of the present invention.

[0040] The illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0041] Example 1:

[0042] A penetrating electrocatalytic water treatment method with a function of controlling the generation of electrolysis by-products in this embodiment is carried out in a penetrating electrocatalytic device, and the device includes:

[0043] An electrochemical reaction cell filled with an electrolyte solution;

[0044] A cathode, and the cathode is a H*-rich electrode;

[0045] An anode, where the anode is an electrode with a low oxygen evolution potential;

[0046] A DC power supply, where the power supply applies a voltage to the cathode and the anode;

[0047] A peristaltic pump, where the peristaltic pump controls the water flow direction to make it pass through the electrode;

[0048] The described penetrative electrocatalytic water treatment method includes:

[0049] Adding an electrolyte solution to the penetrative electrocatalytic device;

[0050] Adding the pollutants to be treated to the reaction tank;

[0051] The described peristaltic pump controls a certain flow rate and controls the water flow direction to be from the anode to the cathode;

[0052] Applying a voltage between the cathode and the anode, and the O2 evolved at the anode is carried by the water flow to the surface of the cathode through convective forced mass transfer and is further activated by cathode H* to form ·OH, thereby treating the pollutants.

[0053] The following performance tests were carried out on the solution of Example 1:

[0054] 1. Preparation and structural characterization test of Pd / CFF electrode

[0055] The Pd / CFF electrode was prepared by electrodeposition in a three - electrode system using cyclic voltammetry (CV). First, the carbon fiber felt (CFF) substrate material was immersed in a 50 mM NH4Cl electrolyte containing 1 mM PdCl2. Using CFF as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl (0.197V vs SHE) as the reference electrode, the potential was set in the range of +0.3 to -0.4V vs SHE, and the scan rate was 5mV s -1 , and 15 CV cycles were carried out.

[0056] As Figure 2 shown, polyhedral Pd particles with sizes in the range of 200 - 300 nm were uniformly deposited on the surface of CFF, and the overlap in the elemental mapping diagrams of C and Pd also confirmed the uniform distribution of Pd on CFF, and the Pd element accounted for about 5.1%.

[0057] As Figure 3 shown, the XPS spectrum of the Pd / CFF electrode presented two characteristic peaks at 340.9 eV and 335.6 eV, corresponding to Pd 0 of Pd 3d 5 / 2 and Pd 3d 3 / 2Spin-orbit coupling demonstrated the successful deposition of Pd. The diffraction peaks at 40.2° and 46.7° in the XRD pattern corresponded to the (111) and (200) crystal planes of Pd, respectively, further confirming the presence of crystalline Pd on the CFF surface. In addition, the highly exposed Pd(111) plane was theoretically capable of enhancing the activity of the electrode to generate H* at negative potentials.

[0058] 2. Feasibility verification of H* generation and its MOA on the Pd / CFF electrode

[0059] As Figure 4 shown in a, in an oxygen-free atmosphere, a characteristic oxidation peak appeared at 0.00 - 0.40 V vs SHE during CV scanning, corresponding to adsorbed atomic H* (H* ads ), proving the generation of H* on the Pd / CFF cathode. This also indicated that H* ads was its main hydrogen species, indicating its efficient H* ads generation / storage capacity, and H* ads had the strongest reducing power among all hydrogen species, showing the highest reduction activity.

[0060] As Figure 4 shown in b, in an oxygen-free atmosphere, nine characteristic peaks of DMPO-H were observed in the ESR spectrum, further confirming the formation of H* on the Pd / CFF cathode. In an oxygen-containing atmosphere, the DMPO-H signal on the Pd / CFF cathode disappeared, and a typical DMPO-OH signal with a peak intensity ratio of 1:2:2:1 appeared, which provided evidence for the activation of O2 to ·OH mediated by H*. In addition, a weak peak of DMPO-OOH was also observed, indicating that *OOH might be a transient intermediate. Further adding H2O2 to the system, the DMPO-OH signal immediately enhanced, indicating the rapid conversion of H2O2 to ·OH. These results proved that the MOA path mediated by H* was: O2 → *OOH → H2O2 → ·OH. And there were no such phenomena on the Pd-free CFF electrode, indicating the important role of Pd in the activation of O2 to generate ·OH mediated by H*.

[0061] 3. Important roles of H* generation at the cathode and oxygen supply at the anode in the OER / MOA through-flow electrocatalytic water treatment method

[0062] Using Figure 1 the through-flow electrocatalytic device, a peristaltic pump was used for circulating flow, controlling the water flow direction from the anode to the cathode, and the water flow rate was 10 mL min -1 . The simulated pollutant water was 10 mg L -1 of 2,4-dichlorophenol (2,4-DCP), the electrolyte was 0.1 M Na2SO4, and the electrolysis time was 45 min. As Figure 5As shown in Fig. a, with the change of the cathode potential, the removal rate of 2,4-DCP using the Pd-containing Pd / CFF cathode is 1.6 - 2.9 times that of the Pd-free CFF cathode, further indicating that Pd plays an important role in MOA. The removal rate of 2,4-DCP increases from 64.5% (-0.4 V vs SHE) to 84.7% (-0.5 V vs SHE), and then decreases to 68.1% (-0.7 V vs SHE), indicating that the H* concentration on the surface of the Pd / CFF cathode reaches an equilibrium state at a cathode potential of -0.5 V vs SHE.

[0063] As Figure 5 shown in Fig. b, anode materials with different oxygen evolution potentials have different removal effects. The coated titanium electrode (DSA) has been commercially used in the field of water treatment. In recent years, the titanium suboxide (TiSO) electrode has been widely used in electrochemical advanced oxidation technology due to its high oxygen evolution potential and high stability. Therefore, in this invention, three anodes, namely CFF, DSA, and TiSO, are selected for comparison. At an anode potential of 1.7 V vs SHE, the water flow-driven systems based on the DSA (0.049 min -1 )) and the CFF anode (0.044 min -1 ) show comparable removal rates, both of which are much higher than that of the TiSO anode (0.013 min -1 ). This is because DSA and CFF have a lower oxygen evolution potential (~1.5 V vs SHE) and can provide sufficient O2, indicating that the O2 supply plays an important role in the H*-mediated MOA. When the water flow direction changes from anode to cathode to from cathode to anode, the removal rate is inhibited by 2.1 times ( Figure 5 Fig. c), indicating that the mass transfer of O2 is also very important.

[0064] 4. Decontamination performance of the OER / MOA through-flow electrocatalytic water treatment method at different flow rates

[0065] Using Figure 1 the through-flow electrocatalytic device, Pd / CFF (inner diameter 6 cm, height 9 cm) and CFF (inner diameter 4 cm, height 9 cm) tubular electrodes are used as the anode and cathode respectively, a peristaltic pump is used for circulating flow, and the water flow direction is controlled from anode to cathode to construct the OER / MOA through-flow electrocatalytic water treatment method. The simulated pollutant water is 10 mg L -1 of 2,4-dichlorophenol (2,4-DCP), the electrolyte is 0.1 M Na2SO4, and the electrolysis time is 45 min. Theoretically, the increase in water flow velocity can promote the convective mass transfer of O2 to the Pd / CFF cathode, and then generate ·OH through the H*-mediated MOA. As Figure 6 shown in Fig. a, the ·OH concentration increases from 59.2 μmol L -1Increased to 245.3 μmol L -1 . As Figure 6 shown in b, in the range of 5 - 30 mL min -1 , the removal rate of 2,4-DCP increased from 61.6% to 94.8%, and the rate constant increased from 0.019 min -1 to 0.116 min -1 . Further increasing the flow rate to 30 mL min -1 to 60 mL min -1 , the removal rate did not change significantly, only increasing by 1.1%. During this process, as Figure 6 shown in c, the current efficiency increased from 8.5% (5 mL min -1 ) to 34.8% (30 mL min -1 ), and then slightly decreased to 33.2% (60 mL min -1 ). The energy consumption also showed a similar trend, decreasing from 3.6 kWh m -3 (5 mL min -1 ) to 1.0 kWh m -3 (30 mL min -1 ), and then slightly increasing to 1.2 kWh m -3 (60 mL min -1 ). These indicate that although increasing the flow rate can theoretically enhance mass transfer to improve the decontamination performance, however, too high a flow rate will cause too low a water residence time, inhibiting the decontamination effect. Therefore, in this embodiment, the optimal flow rate for controlling the OER / MOA penetration electrocatalytic water treatment method is 30 mL min -1 .

[0066] 5. Comparison between the OER / MOA Penetration Electrocatalytic Water Treatment Method and Traditional EAOPs

[0067] Traditional EAOPs rely on inert anodes, and under the combined action of direct oxidation and indirect oxidation of ·OH generated at the anode, the organic pollutants in water are oxidized and degraded. While the OER / MOA penetration electrocatalytic water treatment method uses O2 generated at the anode, which is activated by the cathode to form ·OH, which changes the generation method of ·OH. For this reason, the present invention selects the anodic electrocatalytic method of titanium suboxide (TiSO), which is commonly used in traditional EAOPs, for comparison with this OER / MOA penetration electrocatalytic method. A traditional EAOP (anodic potential of 2.9 V vs SHE, cathodic potential of -1.4 V vs SHE) with a TiSO anode and a CFF cathode is compared with the OER / MOA penetration electrocatalytic water treatment method (anodic potential of 1.7 V vs SHE, cathodic potential of -0.5 V vs SHE). As Figure 7As shown in a-b, when the removal performance of the two systems is comparable (40 min, 95% removal rate), the current efficiency of the OER / MOA system (34.8%) is about 3.5 times that of the traditional EAOP (10.0%), and the energy consumption decreases by 4.3 times, which proves that the OER / MOA penetrative electrocatalytic water treatment method has higher decontamination performance.

[0068] In addition, compared with the high anodic potential (>2.5V vs SHE) applied by traditional EAOPs, the anodic potential required for the OER / MOA penetrative electrocatalytic water treatment system is lower (<2.0V vs SHE). As Figure 7 shown in c, 3 mM NaCl was added to the electrolysis system to study the generation of chlorinated by-products. 2.9 μM of free chlorine and 2.8 μM of organic chlorinated products were detected in the OER / MOA system, and no other chlorinated by-products were detected. While higher concentrations of free chlorine (23.9 μM), 5.4 μM of ClO2 - , 8.2 μM of ClO3 - , 5.2 μM of ClO4 - , and 61.1 μM of organic chlorinated products were observed in the traditional EAOP. This is mainly because the anodic potential required for the OER / MOA system is only 1.7V vs SHE, which controls the formation of chlorinated by-products at the source by Cl - under anodic polarization. Therefore, this method can not only change the generation pathway of ·OH, but also control the generation of toxic by-products.

[0069] 6. Applicability evaluation of the OER / MOA penetrative electrocatalytic water treatment method

[0070] The stability of the process was evaluated by continuous 10-cycle electrolysis and complex water matrices. As Figure 8 shown in a, after 10 consecutive cycle tests, the removal rate of 2,4-DCP can be maintained at 92.4±1.4%, and the attenuation degree is only 3.6%; as Figure 8 shown in b, the removal rates of the OER / MOA penetrative electrocatalytic water treatment method for tap water and river water samples can reach 89.8% and 82.5% respectively. These preliminarily verify the applicability of this method in actual water treatment applications.

Claims

1. A penetrating electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products, characterized in that In the through-type electrocatalysis, the cathode used is a hydrogen-rich atom electrode; the anode is an electrode with a low oxygen evolution potential; and the flow direction of the electrolyte is controlled to flow from the anode to the cathode; the applied cathode potential is -0.4 to -0.7 V vs SHE, and the anode potential is 1.5 to 2.0 V vs SHE; the hydrogen-rich atom electrode is a palladium-containing through-type porous tubular electrode; the low oxygen evolution potential electrode is a through-type porous tubular electrode of carbon-based or metal and its oxide.

2. A penetration-type electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products according to claim 1, characterized in that The hydrogen-rich atomic electrode is a Pd-containing penetrative porous tubular electrode, and the Pd-containing penetrative porous tubular electrode is prepared by cyclic voltammetry scanning electrodeposition method: Immerse the porous conductive substrate material in a 50 mM NH4Cl electrolyte containing 1-10 mM PdCl2, the starting potential of cyclic voltammetry scanning is 0.1-0.5 V vs SHE, the ending potential is -0.6--0.2 V vs SHE, and the scanning rate is 1-10 mV s -1 , and the number of cyclic scans is 5-30 cycles.

3. A penetration-type electrocatalytic water treatment method with a function of controlling the generation of electrolysis by-products according to claim 1, characterized in that The electrolyte is a sodium sulfate or sodium perchlorate solution with a concentration of 5 mM to 500 mM.

4. A penetrating electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products according to claim 1, characterized in that The flow rate of the electrolyte water stream is 5 mL / min -1 to 60 mL / min -1 .

5. A penetration-type electrocatalytic water treatment method with a function of controlling the generation of electrolysis by-products according to claim 1, 3 or 4, characterized in that Add the pollutants to be treated into the reaction cell of the through-type electrocatalytic reaction.

6. The penetration-type electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products according to claim 5, wherein The pollutants to be treated are organic pollutants, and the organic pollutants are phenolic pollutants.

7. A penetrating electrocatalytic water treatment method with a function of controlling the generation of electrolysis by-products according to claim 6, characterized in that The concentration of the organic pollutant is 1 mg / L -1 ~20 mg / L -1 .

8. A penetrating electrocatalytic water treatment method with the function of controlling the generation of electrolysis by-products according to claim 6, characterized in that After adding the pollutants to be treated, the electrocatalytic water treatment time is 10 min to 180 min.

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