Method for treating organic phosphonic acid wastewater by using supported copper monatomic catalyst

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for treating organic phosphonic acid wastewater by using a supported copper monatomic catalyst, which comprises the following steps: adding persulfate and the supported copper monatomic catalyst into the organic phosphonic acid wastewater to degrade organic phosphonic acid; the supported copper monatomic catalyst is a metal oxide loaded with copper monatomic atoms, and the loading amount of the copper monatomic atoms is 1-10 wt% of the total weight of the catalyst. Compared with the prior art, the problem that metal ions cannot be recycled in organic phosphonic acid wastewater treatment of an advanced oxidation process in the prior art is solved. The scheme provides an advanced oxidation technology for organic phosphonic acid wastewater, efficient and deep degradation of organic phosphonic acid in the wastewater is realized, the method can adapt to wastewater in a wider pH range, the metal leaching content is extremely low (0.0015 mg / L) after multiple degradation, and the method has strong anti-interference performance and high selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst. Background Art

[0002] Organophosphonic acid (OPA) is a significant phosphorus-containing pollutant in water. Its accumulation in natural water bodies can pose a range of environmental hazards. Conventional inorganic phosphorus removal technologies are ineffective in removing OPA. Therefore, developing highly efficient OPA removal technologies to completely degrade OPA into readily treatable inorganic phosphorus is crucial.

[0003] Currently, homogeneous copper-based advanced oxidation technology is considered an effective method for removing organic phosphonic acids. This method degrades organic phosphonic acids by selectively generating trivalent copper (Cu(III)) in an activated peroxide reaction, as shown in "Self-Enhanced Selective Oxidation of Phosphonate into Phosphate by Cu(II) / H2O2: Performance, Mechanism, and Validation" (Environmental Science & Technology) and "Efficient degradation of phosphonate via trace Cu(II)mediated activation of peroxymonosulfate" (Process Safety and Environmental Protection). However, homogeneous copper-based advanced oxidation technology cannot be used in actual organic wastewater treatment due to the problem of metal ion loss.

[0004] Among many copper-based catalysts, copper single-atom catalysts have the advantages of high atomic utilization, clear active site structure, and structural regulation from the perspective of molecular design. Compared with copper-based oxides, hydroxides and other materials, they can better control the problem of metal ion dissolution, thereby realizing a single heterogeneous reaction.

[0005] For example, CN114505087A discloses the preparation of a copper single-atom catalyst and its application in the degradation of organic pollutants, specifically the degradation of phenolic compounds, oxygen-containing or nitrogen-containing heterocyclic compounds that are easily oxidized and degraded, including compounds such as bisphenol A (BPA), phenol, 2,4-dichlorophenol (DCP), ciprofloxacin (CIP) or rhodamine B (RhB); however, the materials used in this prior art are mainly suitable for phenolic compounds that are easily oxidized and degraded, and it is mainly aimed at the activation of PDS to achieve the degradation of organic pollutants by advanced oxidation processes; and this scheme uses nitrogen-doped graphene as a carrier of copper single atoms, which does not have the characteristics of mutual combination and interaction with organic phosphonic acid. Therefore, when facing organic phosphonic acid wastewater, the carrier cannot produce a synergistic effect, so that the overall treatment efficiency is still at a relatively low level.

[0006] For example, CN118847115A discloses a Cu1 / TiO2 single-atom catalyst and its preparation method, prepared via a hydrothermal reaction, and capable of photocatalytically degrading the organophosphate DMMP. However, this solution primarily targets the degradation of DMMP and requires additional energy for degradation, resulting in a high degree of dependence on external environmental requirements and a lack of universal applicability in various natural environments. Furthermore, the nitrogen atom catalyst disclosed in this prior art must be prepared via a hydrothermal reaction, which imposes stringent production conditions, is difficult, and expensive.

[0007] Therefore, there is a lack of research on heterogeneous copper-based catalysts for organophosphonic acids in advanced oxidation technologies. Therefore, developing heterogeneous copper-based advanced oxidation technologies, improving their resistance to matrix interference, and achieving selective oxidation of organophosphonic acids are of great significance for advanced water treatment. Summary of the Invention

[0008] The present invention aims to address at least one of the aforementioned issues by providing a method for treating organophosphonic acid wastewater using a supported copper single-atom catalyst. This method addresses the problem of metal ion recovery in prior advanced oxidation processes for treating organophosphonic acid wastewater. This proposal provides an advanced oxidation technology for treating organophosphonic acid wastewater, achieving efficient and deep degradation of organophosphonic acid in wastewater. It is adaptable to wastewater with a wide pH range, exhibits extremely low metal leaching levels (0.0015 mg / L) after multiple degradation steps, and exhibits strong anti-interference properties and high selectivity.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst, comprising adding persulfate and the supported copper single-atom catalyst to the organic phosphonic acid wastewater to degrade the organic phosphonic acid;

[0011] The supported copper single atom catalyst is a metal oxide supported with copper single atoms, wherein the supported amount of the copper single atoms is 1-10 wt% of the total weight of the catalyst.

[0012] Preferably, the organic phosphonic acid is one or more of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediamine tetramethylene phosphonic acid and diethylenetriamine penta methylene phosphonic acid.

[0013] Preferably, the persulfate is a peroxymonosulfate with an asymmetric structure.

[0014] Preferably, the metal oxide is one or more of zirconium dioxide, titanium dioxide and zinc oxide.

[0015] Preferably, the supported copper single-atom catalyst is prepared by the following method:

[0016] Step 1: ultrasonically disperse the metal oxide in ultrapure water, and dropwise add a copper source to the suspension to form solution A;

[0017] Step 2: adding aqueous ammonia solution dropwise to solution A to react and adjusting the pH of the solution, separating the precipitate and washing and drying it to obtain a precursor;

[0018] Step three: calcining the precipitate in an air atmosphere, washing and drying to obtain the supported copper single atom catalyst.

[0019] Preferably, in step 1, the copper source is one or both of copper chloride and copper nitrate.

[0020] Preferably, in step 1, in the solution A, the concentration of the metal oxide is 5 g / L, and the concentration of the copper source is 50-300 mg / L.

[0021] Preferably, step 2 includes one or more of the following:

[0022] i) the concentration of the ammonia solution is 1-4 mol / L;

[0023] ii) the reaction time is 2-5h;

[0024] iii) The pH of the solution is adjusted to 9-9.5.

[0025] Preferably, step three includes one or both of the following:

[0026] i) the calcination temperature is 400-600° C.;

[0027] ii) The drying temperature is 80-100° C. and the drying time is 24-48 hours.

[0028] Preferably, the supported copper single-atom catalyst activates persulfate in organic phosphonic acid wastewater at pH = 9 and completes the degradation of organic phosphonic acid within 30 minutes;

[0029] in,

[0030] The supported copper single atom catalyst is zirconium dioxide loaded with copper single atoms, and the loading amount of copper single atoms is 6 wt% of the total weight of the catalyst; the dosage of the supported copper single atom catalyst is 0.01-1 g / L;

[0031] The persulfate is peroxymonosulfate, and the dosage of the persulfate is 0.1-5 mmol / L.

[0032] The concentration of organic phosphonic acid (such as hydroxyethylidene diphosphonic acid) in organic phosphonic acid wastewater is 0.01-0.5 mmol / L.

[0033] The working principle of the present invention is:

[0034] First, the -PO(OH)2 group in the organophosphonic acid molecule coordinates with the metal site in the Cu-metal oxide to form a surface complex (Cu(II)-metal oxide-organophosphonic acid complex). This Cu(II)-metal oxide-organophosphonic acid complex regulates the electron density of Cu, making it more conducive to reaction with peroxymonosulfate. In the presence of peroxymonosulfate, Cu(II)-metal oxide-organophosphonic acid is oxidized to form Cu(III)-metal oxide-organophosphonic acid. Then, the highly active Cu(III)-metal oxide-organophosphonic acid complex spontaneously decomposes into Cu(II) and PO4 through the ligand-to-metal charge transfer (LMCT) process. 3 The regenerated Cu(II) then coordinates with another organophosphonic acid molecule to start the next catalytic cycle.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] This invention provides a method for degrading organic phosphonic acid in water using peroxymonosulfate (PMS) activated by a supported copper single-atom catalyst. The method is carried out at room temperature and pressure, is simple to operate, requires no external energy, and is adaptable to a wide pH range. It has promising application prospects in the treatment of water bodies contaminated by organic phosphonic acid.

[0037] 1. Wide range of applications: Copper single-atom catalysts supported on different metal oxide carriers can activate PMS and achieve 100% degradation of the organic phosphonic acid HEDP; among them, the prepared Cu-ZrO2 catalyst has the best activation effect on PMS, can effectively degrade a variety of organic phosphonic acids, and has a good effect on the organic phosphonic acid HEDP in a wide pH range (6-10).

[0038] 2. Superior catalytic performance: The prepared copper single-atom catalyst, Cu-ZrO2, activated PMS at pH 9, achieving 100% degradation of the organic phosphonic acid HEDP within 30 minutes. Compared to the homogeneous Cu(II) / PMS system, HEDP degradation efficiency was significantly improved.

[0039] 3. Excellent stability: The prepared single-atom catalyst Cu-ZrO2 activated PMS still maintains a degradation efficiency of more than 95% after 6 cycles of degradation of organic phosphonic acid, and the leaching content of metallic Cu is extremely low (0.0015 mg / L).

[0040] 4. Highly selective anti-interference: in Cl-, SO4 2 -, NO3-, CO3 2 Under the coexistence conditions of competing anions such as - and humic acid, the degradation efficiency of organic phosphonic acid HEDP in the Cu-ZrO2 activated PMS system still reaches 95%, which is suitable for complex water quality environments.

[0041] Compared to the prior art CN114505087A, this solution utilizes metal sites within the metal oxide support that specifically bind to organophosphonic acid, thus serving as binding sites for the acid. This facilitates adsorption of the acid onto the catalyst surface, shortening the interaction distance between the active substance and the acid, and enhancing the degradation efficiency of the acid. Furthermore, compared to the symmetrical structure of PDS, the asymmetric structure of PMS is more easily activated by single copper atoms to produce active substances, further enhancing the degradation efficiency of the acid.

[0042] Compared to CN118847115A, this solution does not require strict hydrothermal conditions; it is obtained through simple adsorption precipitation followed by calcination. This method is simple to prepare, has low production costs, and is suitable for large-scale batch production. Furthermore, this solution has a strong degradation effect on various organophosphonic acids in water, maintaining a high degradation effect despite various interference factors, making it suitable for treating organophosphonic acid wastewater in complex natural environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a diagram showing the effect of using copper single-atom catalysts supported by three different metal oxides to activate PMS and degrade organophosphonic acid HEDP in Application Example 1;

[0044] Figure 2 The degradation effect diagram of HEDP by different systems in Application Example 1 and Comparative Example 1;

[0045] Figure 3 This is the effect diagram of HEDP degradation by Cu-ZrO2 / PMS system after 6 cycles in Application Example 2;

[0046] Figure 4 The figure shows the degradation effect of Cu-ZrO2 activated PMS on different organic phosphonic acids in Comparative Example 3;

[0047] Figure 5 This is a diagram showing the degradation effect of HEDP by the Cu-ZrO2 / PMS system and the homogeneous Cu(II) / PMS system under different pH conditions in Application Example 6. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] In the following description, unless otherwise specified, the reagents used are conventional commercial products in the field, the methods used are well-known means in the field, and other matters not mentioned can adopt existing technologies.

[0050] A method for removing organic phosphonic acid (especially HEDP) from water using a supported copper single-atom catalyst:

[0051] The supported copper single-atom catalyst used is a metal oxide carrier, copper is supported on the metal oxide in the form of a single atom, and the supported amount of Cu is 1-10 wt% based on the total weight of the catalyst.

[0052] The preparation method of the supported copper single-atom catalyst is as follows:

[0053] Step 1: ultrasonically disperse the metal oxide in ultrapure water, and slowly add the copper solution dropwise to the suspension while vigorously stirring to form solution A;

[0054] Step 2: preparing an ammonia solution;

[0055] Step 3, adding aqueous ammonia solution dropwise to solution A to adjust the pH of the solution;

[0056] Step 4: Filter and separate the precipitate formed in step 3, and wash and dry it.

[0057] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and dried in an oven to obtain a supported copper single atom catalyst.

[0058] in,

[0059] In step 1, solution A is prepared by dissolving a metal oxide and a divalent copper source in water; the metal oxide is one or more of zirconium dioxide (ZrO2), titanium dioxide (TiO2), and zinc oxide (ZnO); and the divalent copper source is copper chloride and / or copper nitrate. The amount of the metal oxide in solution A is 5 g / L, and the amount of the copper source is 50-300 mg / L.

[0060] In step 2, the concentration of the ammonia solution is 1-4 mol / L.

[0061] In step 3, the pH adjustment range is 9-9.5, and the reaction time is 2-5 hours.

[0062] In step 4, the calcination temperature is 400-600° C.; the washing is to neutrality; the drying temperature is 80-100° C.; and the drying time is 24-48 hours.

[0063] The supported copper single-atom catalyst degrades organic phosphonic acid in organic phosphonic acid wastewater by activating peroxymonosulfate with an asymmetric structure. The degradation process is carried out at room temperature and pressure, is simple to operate, does not require the addition of external energy, has a wide pH adaptability range, and has good application prospects in the field of water treatment contaminated by organic phosphonic acid. The organic phosphonic acid is one or more of hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylene phosphonic acid (ATMP), ethylenediaminetetramethylenephosphonic acid (EDTMP), and diethylenetriaminepenta(methylenephosphonic acid) (DTPMP). Specifically, when the concentration of the organic phosphonic acid (such as hydroxyethylidene diphosphonic acid) in the organic phosphonic acid wastewater is 0.01-0.5 mmol / L, the dosage of the supported copper single-atom catalyst is 0.01-1 g / L, and the dosage of the peroxymonosulfate is 0.1-5 mmol / L, excellent organic phosphonic acid degradation effect can be achieved.

[0064] Common metal oxides (such as ZrO2, TiO2 and ZnO) have become ideal support materials for the preparation of single-atom catalysts due to their superior structural stability, wide pH range and good metal loading capacity. Since the chemical environment of the copper site on the surface of heterogeneous catalysts is much more complex than that of homogeneous copper ions, the catalytic performance of the copper site will be affected by the support. At the same time, the interaction between the support and the phosphonic acid group will affect the formation and structure of the surface complex. Among them, for the preferred embodiment of this scheme, since Zr has a strong affinity for the phosphonic acid group in the organic phosphonic acid, it is expected that ZrO2 will be selected as the preferred support. The Zr in the metal support forms a strong complex structure with the organic phosphonic acid, thereby affecting the electronic structure and catalytic activity of the active site, while exposing more copper sites for PMS activation.

[0065] This method is characterized by the efficient activation of peroxymonosulfate by a metal oxide-supported copper single-atom catalyst, generating high-valent Cu(III), followed by intramolecular electron transfer within the complex to degrade the organic phosphonic acid. This method is highly effective in removing organic phosphonic acids from water, achieving a 100% removal rate for various organic phosphonic acids within 120 minutes at a pH of 9. This method addresses the issues of metal ion secondary contamination and slow Cu(II) / Cu(I) cycling in copper-based homogeneous advanced oxidation technologies. Furthermore, this method offers the advantages of rapid Cu(III) generation, efficient pollutant removal, a wide pH range, and strong anti-interference properties, making it particularly suitable for treating water contaminated by organic phosphonic acids.

[0066] Example 1

[0067] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 1wt%;

[0068] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0069] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0070] Step 2: dissolving ammonia in water to obtain solution B;

[0071] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0072] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0073] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a supported copper single atom catalyst.

[0074] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 50 mg / L; the concentration of ammonia water is 1 mol / L; the pH in step three is adjusted and maintained at 9; the reaction time in step three is 2 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 80°C, and the drying time is 24 hours.

[0075] Example 2

[0076] A supported copper single-atom catalyst: the carrier is TiO2, and the copper loading is 2wt%;

[0077] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0078] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0079] Step 2: dissolving ammonia in water to obtain solution B;

[0080] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0081] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0082] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a supported copper single atom catalyst.

[0083] Among them, the metal oxide in step one is TiO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 100 mg / L; the concentration of ammonia water is 2 mol / L; the pH in step three is adjusted and maintained at 9; the reaction time in step three is 3 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 90°C, and the drying time is 24 hours.

[0084] Example 3

[0085] A supported copper single-atom catalyst: the carrier is ZnO, and the copper loading is 4 wt%;

[0086] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0087] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0088] Step 2: dissolving ammonia in water to obtain solution B;

[0089] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0090] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0091] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a supported copper single atom catalyst.

[0092] Among them, the metal oxide in step one is ZnO, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 200 mg / L; the concentration of ammonia water is 3 mol / L; the pH in step three is adjusted and maintained at 9; the reaction time in step three is 4 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 100°C, and the drying time is 36 hours.

[0093] Example 4

[0094] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 4wt%;

[0095] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0096] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0097] Step 2: dissolving ammonia in water to obtain solution B;

[0098] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0099] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0100] Finally, the precursor was calcined in air atmosphere, washed with anhydrous ethanol and ultrapure water for multiple times, and then dried in an oven to obtain Cu-ZrO2.

[0101] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 200 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9; the reaction time in step three is 4 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 80°C, and the drying time is 24 hours.

[0102] Example 5

[0103] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0104] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0105] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0106] Step 2: dissolving ammonia in water to obtain solution B;

[0107] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0108] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0109] Finally, the precursor was calcined in air atmosphere, washed with anhydrous ethanol and ultrapure water for multiple times, and then dried in an oven to obtain Cu-ZrO2.

[0110] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9.5; the reaction time in step three is 5 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 100°C, and the drying time is 48 hours.

[0111] Application Example 1

[0112] Preparation of supported copper single-atom catalysts: the supports are ZrO2, TiO2 and ZnO, and the copper loading is 6wt%;

[0113] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0114] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0115] Step 2: dissolving ammonia in water to obtain solution B;

[0116] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0117] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0118] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a copper single atom catalyst.

[0119] Among them, the metal oxides in solution A in step 1 are ZrO2, TiO2 and ZnO, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 200 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step 3 is adjusted and maintained at 9.5; the reaction time in step 3 is 5 hours; the precipitate in step 4 is washed to neutrality; the drying temperature in step 4 is 80°C and the drying time is 24 hours.

[0120] The three catalysts (Cu-ZrO2, Cu-TiO2 and Cu-ZnO) prepared in Example 1 were tested for their performance in activating PMS to degrade HEDP. The HEDP concentration was 0.1 mmol / L, the catalyst dosage was 0.2 g / L, and the PMS dosage was 2 mmol / L. When the wastewater pH was 9, after 60 minutes of reaction, the three catalysts, in the presence of PMS, could achieve a 100% removal rate for the degradation of the organic phosphonic acid HEDP. Among them, the Cu-ZrO2 / PMS system had the best degradation effect on organic phosphonic acid, as shown in Figure 2. Figure 1 As shown in the figure, 100% removal rate was achieved in about 30 min.

[0121] Comparative Example 1-1

[0122] PMS was activated by metal oxides ZrO2, TiO2 or ZnO without copper loading, and the organic phosphonic acid HEDP was degraded in the presence of Cu-ZrO2, Cu-TiO2, Cu-ZnO (loading amount and preparation method were the same as those in Application Example 1) or PMS (i.e., the above substances were added to the organic phosphonic acid wastewater and tested under the same test conditions as in Application Example 1).

[0123] like Figure 2 As shown, in the PMS system activated by unsupported copper metal oxides ZrO2, TiO2, or ZnO, the degradation rate of the organophosphonic acid HEDP was only 0.5%-5%. Cu-ZrO2, Cu-TiO2, or Cu-ZnO alone had no effect on HEDP degradation. Furthermore, when PMS was present alone, the HEDP degradation rate was only 15%. Therefore, only when this supported copper single-atom catalyst and PMS coexist and work synergistically can they achieve a good degradation effect on organophosphonic acids.

[0124] Comparative Example 1-2

[0125] A copper single-atom catalyst (Cu-C3N4) supported on carbon nitride was prepared (the specific loading amount and preparation method are the same as in Application Example 1, wherein the main difference in the preparation method is that the metal oxide is replaced with carbon nitride in step one, and the rest remains the same), and it was used to activate PMS to degrade HEDP (tested under the same test conditions as Application Example 1). In the Cu-C3N4 / PMS system, when the wastewater pH is 9, after 120 minutes of reaction time, the HEDP degradation rate is 65%, which is lower than that of the Cu-ZrO2 / PMS system. This is because the metal on the metal oxide support has a strong binding ability for organic phosphonic acid, making it easier to adsorb organic phosphonic acid to the catalyst surface, shortening the interaction distance with the active substance and improving the degradation effect of organic phosphonic acid.

[0126] Application Example 2

[0127] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0128] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0129] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0130] Step 2: dissolving ammonia in water to obtain solution B;

[0131] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0132] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0133] Finally, the precursor was calcined in air atmosphere, washed with anhydrous ethanol and ultrapure water for multiple times, and then dried in an oven to obtain Cu-ZrO2.

[0134] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9.5; the reaction time in step three is 4 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 90°C, and the drying time is 24 hours.

[0135] The sample prepared in Example 2 was tested for the performance of HEDP degradation by activated PMS. The HEDP concentration was 0.1 mmol / L, the catalyst dosage was 0.2 g / L, and the PMS dosage was 2 mmol / L. Figure 3 As can be seen from the figure, when the wastewater pH is 9, the prepared Cu-ZrO2 activated PMS still maintains a degradation efficiency of more than 95% after 6 cycles of HEDP degradation, and the leaching content of metal Cu is extremely low (0.0015 mg / L).

[0136] Application Example 3

[0137] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0138] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0139] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0140] Step 2: dissolving ammonia in water to obtain solution B;

[0141] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0142] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0143] Finally, the precursor was calcined in air atmosphere, washed with anhydrous ethanol and ultrapure water for multiple times, and then dried in an oven to obtain Cu-ZrO2.

[0144] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is cupric chloride, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9.5; the reaction time in step three is 5 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 100°C, and the drying time is 24 hours.

[0145] The sample prepared in Example 3 was used to test the performance of activated PMS in degrading HEDP. The concentration of HEDP was 0.1mmol / L, the catalyst dosage was 0.2g / L, and the PMS dosage was 2mmol / L. When the wastewater pH was 9, the prepared Cu-ZrO2 activated PMS system was subjected to the conditions of Cl-, SO4 2 -, NO3-, CO3 2 Under the coexistence of competing anions such as - and humic acid, the degradation efficiency of organic phosphonic acid HEDP still reaches 95%.

[0146] Application Example 4

[0147] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0148] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0149] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0150] Step 2: dissolving ammonia in water to obtain solution B;

[0151] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0152] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0153] Finally, the precursor was calcined in air atmosphere, washed with anhydrous ethanol and ultrapure water for multiple times, and then dried in an oven to obtain Cu-ZrO2.

[0154] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9.5; the reaction time in step three is 4 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 80°C, and the drying time is 24 hours.

[0155] Comparative Example 2

[0156] The samples prepared in Example 4 were tested for HEDP degradation performance using different activation oxidants (permonosulfate (PMS), peroxydisulfate (PDS), and hydrogen peroxide (H2O2). The HEDP concentration was 0.1 mmol / L, the catalyst dosage was 0.2 g / L, and the PMS dosage was 2 mmol / L. When the wastewater pH was 9, the prepared Cu-ZrO2-activated PMS performed best in degrading the organic phosphonic acid HEDP. This is because PDS and H2O2 both have symmetrical structures, while the asymmetric structure of PMS is more easily activated by copper atoms to produce active species.

[0157] Application Example 5

[0158] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0159] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0160] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0161] Step 2: dissolving ammonia in water to obtain solution B;

[0162] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0163] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0164] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a supported copper single atom catalyst.

[0165] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9.5; the reaction time in step three is 5 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 100°C, and the drying time is 24 hours.

[0166] Comparative Example 3

[0167] The performance test of activating PMS to degrade different organic phosphonic acids was carried out using the samples prepared in Example 5. Among them, the concentration of HEDP was 0.1mmol / L, the catalyst dosage was 0.2g / L, and the PMS dosage was 2mmol / L. Figure 4 As shown, at pH = 9, the prepared Cu-ZrO2 activated PMS system can achieve 100% degradation of different organic phosphonic acids within 120 minutes.

[0168] Application Example 6

[0169] A supported copper single-atom catalyst: the carrier is ZrO2, and the copper loading is 6wt%;

[0170] The method for preparing the supported copper single-atom catalyst comprises the following steps:

[0171] Step 1: dissolving metal oxide and divalent copper source in water to obtain solution A;

[0172] Step 2: dissolving ammonia in water to obtain solution B;

[0173] Step 3: adding solution B dropwise to solution A to obtain a metal precipitate, and adjusting the solution to maintain a certain pH value;

[0174] Step 4: Filter and separate the precipitate obtained in step 3, and wash and dry it.

[0175] Finally, the precursor was calcined in an air atmosphere, washed with anhydrous ethanol and ultrapure water multiple times, and then dried in an oven to obtain a supported copper single atom catalyst.

[0176] Among them, the metal oxide in step one is ZrO2, with a content of 5 g / L; the divalent copper source is copper nitrate, with a content of 300 mg / L; the concentration of ammonia water is 4 mol / L; the pH in step three is adjusted and maintained at 9; the reaction time in step three is 4 hours; the precipitate in step four is washed to neutrality; the drying temperature in step four is 80°C, and the drying time is 36 hours.

[0177] The Cu-ZrO2 prepared in Example 6 was used to activate PMS to test the degradation effect of organic phosphonic acid HEDP under different pH conditions, where the HEDP concentration was 0.1mmol / L, the catalyst dosage was 0.2g / L, and the PMS dosage was 2mmol / L. At the same time, Cu-ZrO2 was added alone to the wastewater for comparison. Figure 5 As shown, the prepared Cu-ZrO2-activated PMS system has a good degradation effect on HEDP over a wide pH range, achieving 100% degradation of HEDP under both neutral and weakly alkaline conditions. Furthermore, under different pH conditions, the Cu-ZrO2 / PMS system significantly improves the degradation of HEDP compared to the homogeneous Cu(II) / PMS system.

[0178] Comparative Example 4-1

[0179] The sample prepared in Example 6 was tested at a HEDP concentration of 0.05 mmol / L, a catalyst dosage of 0.1 g / L, and a PMS dosage of 1 mmol / L. At a wastewater pH of 9, the Cu-ZrO2-activated PMS system achieved 100% HEDP degradation within 60 minutes.

[0180] Comparative Example 4-2

[0181] The sample prepared in Example 6 was tested at a HEDP concentration of 0.4 mmol / L, a catalyst dosage of 0.5 g / L, and a PMS dosage of 4 mmol / L. At a wastewater pH of 9, the prepared Cu-ZrO2-activated PMS system achieved 100% degradation of HEDP within 90 minutes.

[0182] In summary, the technical solution of this application is based on the intersection of environmental functional materials and deep treatment of industrial wastewater. Through atomic-level precise catalyst design, it successfully overcomes the core bottlenecks of low efficiency, high metal dissolution and narrow applicability of traditional processes, and provides an efficient and stable systematic solution for the treatment of organic phosphonic acid contaminated wastewater.

[0183] To address the issues of secondary metal ion contamination and slow cyclic degradation efficiency in homogeneous copper-activated permonosulfate degradation systems for organophosphonic acid, a new scheme employs a support-single-atom synergistic mechanism. Metal oxides such as ZrO2, TiO2, and ZnO are used as supports, and a Cu-OM (M=Zr / Ti / Zn) bonded structure is constructed to firmly anchor copper single atoms. The three catalysts activated by permonosulfate (PMS) all achieved 100% degradation efficiency for the organophosphonic acid HEDP. This degradation technology utilizes the preferential coordination of the -PO(OH)2 groups of organophosphonic acids (such as HEDP) with metal sites on the support surface, forming a "Cu(II)-phosphonic acid-support" ternary complex. Under the action of PMS, this complex is rapidly oxidized to form a highly active Cu(III) species, which directly drives intramolecular charge transfer (LMCT) and efficiently breaks the CP bond (phosphate conversion >98%), avoiding side reactions caused by free radical pathways. The synthesized Cu-ZrO2 activated PMS system can achieve 100% degradation of various organic phosphonic acids; the catalyst is active in the presence of Cl-, SO4 2- It can maintain a HEDP degradation rate of more than 95% in complex water matrices such as humic acid and humic acid; it can maintain an efficiency of more than 90% after being recycled for 5 times; its effective pH range is widened to 6-10 (the traditional Fenton system needs to be strictly controlled at pH≈3), greatly reducing the difficulty and cost of wastewater pretreatment; after the reaction, the copper dissolution rate is about 0.0015mg / L (far below the industrial emission standard of 1mg / L).

[0184] This solution demonstrates adaptability in multiple scenarios. For organic phosphonic acid scale inhibitors (such as HEDP and ATMP) enriched in circulating cooling water treatment (power and petrochemical industries), the Cu single atom / PMS system can achieve almost complete degradation within 30 minutes at room temperature. Compared with biological methods (degradation cycle > 48 hours) and homogeneous oxidation technologies with metal risks, its operating costs can be reduced by more than 40%, and the activity of the catalyst remains above 95% after being recycled 6 times. In addition, this technology is easy to integrate with existing persulfate oxidation equipment. It only requires the addition of a catalyst fixed bed reactor, which can effectively promote the water treatment industry from the high-energy-consuming "chemical precipitation" mode to the efficient and low-consumption "atom-economic catalytic oxidation" mode.

[0185] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst, characterized in that: adding persulfate and the supported copper single-atom catalyst to the organic phosphonic acid wastewater to degrade the organic phosphonic acid; The supported copper single atom catalyst is a metal oxide supported with copper single atoms, wherein the supported amount of the copper single atoms is 1-10 wt% of the total weight of the catalyst.

2. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 1, characterized in that: The organic phosphonic acid is one or more of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediamine tetramethylene phosphonic acid and diethylenetriamine penta methylene phosphonic acid.

3. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 1, characterized in that: The persulfate is a peroxymonosulfate with an asymmetric structure.

4. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 1, wherein: The metal oxide is one or more of zirconium dioxide, titanium dioxide and zinc oxide.

5. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 1, characterized in that: The supported copper single-atom catalyst is prepared by the following method: Step 1: ultrasonically disperse the metal oxide in ultrapure water, and dropwise add a copper source to the suspension to form solution A; Step 2: adding aqueous ammonia solution dropwise to solution A to react and adjusting the pH of the solution, separating the precipitate and washing and drying it to obtain a precursor; Step three: calcining the precipitate in an air atmosphere, washing and drying to obtain the supported copper single atom catalyst.

6. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 5, characterized in that: In step 1, the copper source is one or both of copper chloride and copper nitrate.

7. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 5, characterized in that: In step 1, in the solution A, the concentration of the metal oxide is 5 g / L, and the concentration of the copper source is 50-300 mg / L.

8. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 5, characterized in that: Step 2 includes one or more of the following: i) the concentration of the ammonia solution is 1-4 mol / L; ii) the reaction time is 2-5h; iii) The pH of the solution is adjusted to 9-9.

5.

9. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 5, characterized in that: Step 3 includes one or both of the following: i) the calcination temperature is 400-600° C.; ii) The drying temperature is 80-100° C. and the drying time is 24-48 hours.

10. The method for treating organic phosphonic acid wastewater using a supported copper single-atom catalyst according to claim 1, characterized in that: The supported copper single-atom catalyst activates persulfate in organic phosphonic acid wastewater at pH = 9 and completes the degradation of organic phosphonic acid within 30 minutes; in, The supported copper single atom catalyst is zirconium dioxide loaded with copper single atoms, and the loading amount of copper single atoms is 6 wt% of the total weight of the catalyst; the dosage of the supported copper single atom catalyst is 0.01-1 g / L; The persulfate is peroxymonosulfate, and the dosage of the persulfate is 0.1-5 mmol / L.

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