Method for degrading organophosphorus and recycling phosphorus in water in ozone oxidation system

Abstract

The invention provides a method for degrading organic phosphorus and recycling phosphorus in water in an ozone oxidation system. According to the method, a mode of adding iron or iron salt solution step by step is innovatively adopted, so that the degradation rate of phosphorus-containing organic matters in water, the generation rate of phosphate radicals and the removal of total phosphorus in water are remarkably improved. Besides, the treatment effect is evaluated by monitoring the organophosphorus mineralization rate (taking the generation amount of phosphate radicals as an index) and the removal rate of total phosphorus in water, experiments show that the method can increase the organophosphorus mineralization rate by 30% or above, and the removal rate of total phosphorus reaches 95%. Compared with the conventional one-time addition of iron or iron salt, the method has the advantages that the mineralization rate of organophosphorus and the removal rate of total phosphorus are effectively improved through a step-by-step addition strategy, the direct precipitation of an organophosphorus intermediate product is promoted, the use amount of ozone and the addition amount of iron are remarkably reduced, the reaction time is greatly shortened, and the recovery efficiency of phosphorus resources is further improved. The method is low in cost and suitable for advanced treatment of organic phosphorus-containing wastewater in the industries of pesticides, electroplating and the like.

Description

Technical Field

[0001] The invention belongs to the field of organic phosphorus wastewater treatment, and specifically relates to a method for degrading organic phosphorus in organic phosphorus wastewater and recovering phosphorus in the water by stepwise addition of iron or iron salt in an ozone oxidation system. Background Art

[0002] Organophosphorus compounds have important applications in agriculture, chemical industry, pharmaceutical industry, electronics and other fields due to their unique chemical properties and biological activities. Common phosphorus-containing organic compounds include organophosphorus pesticides such as glyphosate (GLP), glufosinate and parathion, as well as various phosphonate compounds, such as hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid and diethylenetriaminepenta(methylenephosphonic acid). Among them, GLP is widely used in agricultural production as a highly effective herbicide, while the other five phosphonate compounds are commonly used in industrial fields such as textiles, papermaking, building materials, electroplating and petroleum production due to their excellent metal complexing properties.

[0003] Take hexamethylphosphoric acid triamide (HMPA) as an example. HMPA is a colorless, water-miscible organophosphorus solvent that is widely used in the dissolution process of polymers and the reaction medium in organometallic chemistry, and is often used as a standard test substance for method validation. The widespread use of HMPA inevitably leads to the discharge of a large amount of industrial organophosphorus wastewater. Industrial wastewater that is not properly treated will pose a serious threat to the ecological environment and human health. More importantly, toxicological evidence shows that HMPA has significant carcinogenicity (rat nasal tumors) and genotoxicity (fruit fly mutagenesis). Therefore, it is crucial to develop technologies that efficiently degrade organophosphorus and reduce its toxicity. In addition, phosphorus is an essential element for all life. As a limited and non-renewable resource, phosphorus cannot be manufactured and phosphorus recovery is urgently needed. Methods for recovering inorganic phosphorus are relatively mature, but organophosphorus compounds containing CP or COP bonds show remarkable stability, high solubility and resistance to biodegradation. These characteristics make it difficult to degrade organophosphorus using traditional treatment methods. To date, there have been several methods for removing organophosphorus, including adsorption, electrochemical and advanced oxidation processes.

[0004] Ozone catalytic oxidation technology is an important branch of advanced oxidation processes. It activates ozone molecules through catalysts to produce active oxygen species, and can efficiently mineralize various types of organic phosphorus compounds in water bodies. Iron represented by zero-valent iron or divalent iron salts, trivalent iron salt solutions can significantly improve the efficiency of ozone oxidation as catalysts, but their addition method directly affects the reaction effect. In the prior art, a one-time addition method of the catalyst is usually adopted, which is prone to cause local insufficient or excessive catalysts, affecting the efficiency of free radical generation, thereby reducing the phosphorus removal effect, and the efficiency of recovering phosphorus through iron phosphate precipitation is not high. In addition, unreasonable addition methods may also cause iron sludge deposition, low ozone utilization rate and other problems.

[0005] Therefore, it is of great significance to develop an ozone oxidation phosphorus removal method that can optimize the dosing of iron or iron salts for improving the degradation and recovery efficiency of organic phosphorus and reducing the operating cost. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to propose a method for stepwise dosing of iron or iron salts in an economic and efficient ozone oxidation system to achieve the degradation of organic phosphorus in organic phosphorus wastewater and the recovery of phosphorus in water. Aiming at the problems of unstable oxidation efficiency and low utilization rate of medicaments in the existing ozone oxidation phosphorus removal process, the present invention realizes the synergistic effect of the oxidant and the catalyst by establishing a dynamic stepwise dosing mode, and finally improves the degradation of organic phosphorus in water and the recovery of total phosphorus.

[0007] To achieve the above purpose, the method for stepwise dosing of iron or iron salts in an ozone oxidation system to degrade organic phosphorus in organic phosphorus wastewater and recover phosphorus in water is carried out according to the following steps: S1: Under room temperature conditions, add the wastewater containing organic phosphorus compounds into a reaction vessel, then add a specific amount of catalyst, and adjust the pH value by adding acid. S2: Connect the reaction vessel to an ozone generator, open the oxygen cylinder and the ozone generator, adjust the flowmeter, and run the reaction system to uniformly introduce ozone into the reaction vessel. S3: Within a specific time period, sample and measure the phosphate ion concentration and organic phosphorus concentration at time points with the same subsequent time intervals, and sequentially add the same amount of catalyst as in step S1 to the reaction vessel to achieve multiple stepwise dosing of the catalyst. S4: After the reaction is completed, add alkali to the reaction vessel to adjust the pH value, stir and let it stand for precipitation. S5: After the standing in step S4 is completed, filter and measure the phosphate ion concentration, organic phosphorus concentration in the solution, and the amounts of phosphate and organic phosphorus in the precipitate; take another part of the filtered reaction solution and measure the total phosphorus content in the solution.

[0008] A further technical solution is that the catalyst is iron or iron salt, the iron is zero-valent iron, including zero-valent iron powder or nano-zero-valent iron, and in the system of the present invention, the iron powder will slowly release iron salt; the iron salt is a divalent iron salt solution or a trivalent iron salt solution, wherein the divalent iron salt solution includes ferrous sulfate solution, ferrous chloride solution or ferrous nitrate solution, and the trivalent iron salt solution includes ferric sulfate solution, ferric chloride solution or ferric nitrate solution.

[0009] A further technical solution is that the organic phosphorus compound includes one of glyphosate, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylphosphoric triamide, hexamethylenediaminetetramethylenephosphonic acid and diethylenetriamine pentamethylenephosphonic acid.

[0010] For a further technical solution, in step S1, the concentration of the organophosphorus compound is 10 - 20 mg / L; add acid to adjust the pH value to 2 - 4.

[0011] For a further technical solution, the number of times of adding the catalyst is 2 - 10 times, and the time intervals between adjacent additions are equal.

[0012] For a further technical solution, the amount of iron added each time is 0.5 - 1 g or the volume of the iron salt solution added is 10 - 20 mL, and the concentration is 0.5 - 1 g / L.

[0013] For a further technical solution, the process conditions of the ozonation reaction include: the ozone dosage is 150 - 300 mgO3 / h per liter of water, the reaction pH value is 2 - 4, and the reaction temperature is room temperature.

[0014] For a further technical solution, in step S3, the same time interval is every 5 - 10 min, and the specific time period is 60 - 100 min.

[0015] For a further technical solution, in step S4, the alkali added is 0.6 - 1M sodium hydroxide solution, and the pH value is adjusted to 6 - 8.

[0016] The present invention evaluates the degradation efficiency of organophosphorus and the precipitation and recovery effect of phosphorus by monitoring the organophosphorus mineralization rate and the total phosphorus removal rate.

[0017] Among them, the organophosphorus mineralization rate refers to the ratio of the phosphate generated in the system to the organophosphorus in the solution in the initial reaction system, that is, how much organophosphorus is converted into phosphate. The total phosphorus removal rate refers to the ratio of the difference between the sum of the initial phosphorus-containing substances in water and the sum of the dissolved phosphorus-containing substances still present in water after precipitation and recovery to the sum of the initial phosphorus-containing substances in water. It should be noted that the total phosphorus refers to all forms of phosphorus in the reaction system, including phosphate precipitation, organophosphorus precipitation, organophosphorus in water, and phosphate in water; in the initial reaction system, there is only organophosphorus in the solution, and at this time, the organophosphorus in the solution is equal to the total phosphorus. During the reaction process, organophosphorus is gradually degraded into organophosphorus intermediate products and inorganic phosphorus, and some organophosphorus intermediate products and inorganic phosphorus will combine with iron and change from the dissolved state to the non-dissolved state. At this time, the total phosphorus is equal to dissolved organic phosphorus + dissolved inorganic phosphorus + precipitated organic phosphorus + precipitated inorganic phosphorus.

[0018] Preferably, the reaction end point is that the phosphate generation amount reaches about 60% of the theoretical value, and the total phosphorus precipitation recovery rate reaches more than 90%.

[0019] The rapid removal of organic phosphorus in water in the present invention is achieved by increasing the mineralization rate of organic phosphorus and the direct precipitation of organic phosphorus intermediate products. The increase in the mineralization rate of organic phosphorus is because the stepwise addition of iron or iron salts can slow down the hydrolysis rate of iron, maintain a stable concentration of Fe(II) in the solution, avoid the instantaneous generation and hydrolysis precipitation of Fe(III), and thus ensure the continuous supply of active iron species in the reaction system. The increase in the direct precipitation of organic phosphorus intermediate products is because the stepwise addition of iron or iron salts can ensure the continuous replenishment of in-situ Fe(III), make the phosphate radical form a more stable strengite-like structure with the iron salt, thereby enhancing the precipitation ability of inorganic phosphorus. At the same time, it promotes the coprecipitation of organic phosphorus intermediate products in water with iron (hydr)oxides, and thus enhances the precipitation recovery ability of organic phosphorus intermediate products, comprehensively improving the overall precipitation recovery ability of phosphorus in water.

[0020] The method of the present invention is applicable to treating organic phosphorus pollutants in pesticide wastewater, electroplating wastewater or organic phosphorus chemical industrial wastewater.

[0021] Compared with the prior art, the present invention has the following advantages: 1. By establishing a stepwise addition mode, the mineralization rate of organic phosphorus is significantly improved. The core mechanism lies in constructing an efficient iron-catalyzed oxidation system. In this system, the Fe(II) produced by the hydrolysis of the stepwise addition of Fe(II) or zero-valent iron reacts continuously with ozone to generate Fe(III) and hydroxyl radicals. These highly active radicals break the C-P bonds in the organic phosphorus compounds, gradually degrade them into low-molecular-weight organic intermediates and finally mineralize them into phosphate radicals (PO4 3- ). At the same time, the newly generated Fe(III) forms highly reactive iron (hydr)oxides through hydrolysis. The surface of it forms amorphous organic phosphorus-iron complex precipitates with organic phosphorus intermediates through Fe-O-P coordination bonds, while the PO4 3- in the solution combines with Fe(III) to form FePO4 precipitates. The complex formed through the Fe-O-P coordination bond can quickly reduce Fe(III) to Fe(II) through the electron transfer pathway, and Fe(II) continues to react with ozone to continuously generate Fe(III) and hydroxyl radicals. In addition, the iron combined with organic phosphorus intermediate products can continue to exist in the solution to play a catalytic role, avoiding the rapid precipitation and agglomeration of iron.

[0022] 2. By establishing a stepwise dosing mode, direct precipitation removal of some organic phosphorus intermediate products can be achieved. The main reason is that the in-situ generated Fe(III) can form a more stable strengite-like structure (corner-connected PO4 tetrahedra to FeO6 octahedra), showing stronger phosphorus fixation ability. This avoids the adverse phenomenon that direct rapid oxidation of all iron or iron salts added at one time forms Fe(III) and hydrolyzes into iron hydroxides, resulting in their own rapid precipitation. Therefore, stepwise dosing of iron or iron salts can effectively promote the co-precipitation of organic phosphorus intermediate products with iron (hydr)oxides through the highly coordinated Fe-O-P structure.

[0023] 3. By establishing a stepwise dosing mode, not only the mineralization rate of organic phosphorus compounds and the total phosphorus removal rate are significantly improved compared with the one-time dosing method, but also the reaction time is greatly shortened, the ozone dosage and the dosage of iron or iron salts are significantly reduced, realizing efficient and economical degradation and recovery of organic phosphorus compounds. On the basis of achieving the same phosphorus removal effect, compared with one-time dosing, the dosage of iron or iron salts can be reduced by 60%, the ozone dosage can be reduced to 70%, and the reaction time can be shortened to 30% of the original.

[0024] In summary, by stepwise dosing of iron or iron salt solution in the present invention, not only the significant improvement of the organic phosphorus mineralization rate and the total phosphorus removal rate is realized, but also the co-precipitation of inorganic phosphorus and organic phosphorus intermediate products can be promoted, the ozone dosage and the iron dosage can be significantly reduced, and the reaction time is greatly shortened, providing a new technical solution for the treatment of phosphorus-containing wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the reaction system of the present invention.

[0026] Figure 2 It is a schematic diagram comparing the mineralization rate of organic phosphorus by stepwise dosing and one-time dosing of iron or iron salts in the ozone oxidation system provided by the present invention.

[0027] Figure 3 It is a schematic diagram comparing the total phosphorus removal rate by stepwise dosing and one-time dosing of iron or iron salts in the ozone oxidation system provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following further illustrates the content of the present invention with specific examples, but should not be construed as a limitation to the present invention. Without departing from the spirit and essence of the present invention, simple modifications or substitutions made to the methods, steps or conditions of the present invention all belong to the scope of the present invention. If not specifically specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0029] The materials, reagents, etc. used in the following examples can be obtained from commercial channels without special instructions. Example 1 (Stepwise dosing)

[0030] A method for degrading and recovering phosphorus-containing organic matter in water by ten equal-dose additions of ferric salt in an ozone oxidation system is as follows:[[]] Step 1: At room temperature (25 °C), add 17.9 mg / L of HMPA solution to the reaction vessel, add a specific volume of ferrous sulfate solution, and adjust the pH to 3 with 1M HClO4.[[]]

[0031] Step 2: Connect the reaction vessel to the ozone generator, turn on the oxygen source and the ozone generator, and adjust the gas flow rate to 2 L / min (the ozone amount is 250 mg O3 / h per liter of water) to stably introduce ozone into the reaction system.[[]]

[0032] Step 3: During the reaction, take samples every 10 min to measure the phosphate concentration and the organic phosphorus concentration, and add ferrous sulfate solution with the same concentration and the same volume as in Step 1. The total number of additions is 10 times. Take part of the reaction solution, add 1M NaOH, adjust the pH to 7, let it stand for precipitation, filter, and then measure and calculate the phosphate concentration and the organic phosphorus concentration in the solution, as well as the phosphate concentration and the organic phosphorus concentration in the precipitate. Take another part of the filtered reaction solution, measure the total phosphorus content after high-temperature digestion, and calculate the total phosphorus removal rate.[[]]

[0033] Among them, the phosphate concentration is measured by adding ascorbic acid reducing agent and molybdate solution to the solution, coloring for 15 min, measuring the absorbance at a wavelength of 700 nm, and then calculating the concentration according to the standard curve. Phosphate concentration in the precipitate = phosphate concentration in the solution before adjusting the pH and before recovering the precipitate (Data 1) - phosphate concentration in the solution after recovering the precipitate (Data 2), and the initial system is 0; the phosphate concentration in the solution is Data 2, and the initial system is 0. At the same time, add potassium persulfate (oxidant) solution to the initial system and the solution after recovering the precipitate. After high-temperature digestion for 30 min and cooling to room temperature, measure the phosphate concentration in the same way, which is the total phosphorus content (Data 3). At this time, the organic phosphorus concentration in the solution = total phosphorus content in the solution after recovering the precipitate (Data 3) - phosphate concentration in the solution after recovering the precipitate (Data 2), and the organic phosphorus concentration in the precipitate = total phosphorus content in the initial reaction system (Initial Data 3) - phosphate concentration in the solution before recovering the precipitate (Data 1) - total phosphorus content in the solution after recovering the precipitate (Data 3) + phosphate concentration in the solution after recovering the precipitate (Data 2).[[]]

[0034] Note: After adding the oxidant and high-temperature digestion of the solution, all organic phosphorus is converted into phosphate.[[]] Example 2

[0035] The difference between this example and Example 1 is that the number of times of adding ferric salt solution is 5 times.[[]] Example 3

[0036] The difference between this embodiment and Embodiment 1 is that: the organophosphorus in Step 1 is glyphosate. Example 4

[0037] The difference between this embodiment and Embodiment 1 is that: the iron salt solution in Step 1 is ferric chloride solution. Example 5

[0038] The difference between this embodiment and Embodiment 1 is that: the pH value in Step 1 is 4. Example 6

[0039] The difference between this embodiment and Embodiment 1 is that: the temperature in Step 1 is 10 °C. Example 7

[0040] The difference between this embodiment and Embodiment 1 is that: the gas flow rate in Step 2 is 1 L / min (the amount of ozone is 150 mg O3 / h per liter of water). Example 8

[0041] The difference between this embodiment and Embodiment 1 is that: the pH value in Step 3 is 6. Example 9

[0042] The difference between this embodiment and Embodiment 1 is that: the catalyst added is zero-valent iron powder. Comparative Example 1 (one-time addition)

[0043] A method for realizing the degradation of organophosphorus and the recovery of phosphorus in water by one-time addition of iron salt in an ozone oxidation system is as follows: Step 1: At room temperature (25 °C), add a 17.9 mg / L HMPA solution to the reaction vessel, add a specific volume of ferrous sulfate solution at one time, and adjust the pH to 3 with 1M HClO4.

[0044] Step 2: Connect the reaction vessel to the ozone generator, turn on the oxygen source and the ozone generator, adjust the gas flow rate to 2 L / min (the amount of ozone is 250 mg O3 / h per liter of water), and make ozone stably introduced into the reaction system.

[0045] Step 3: During the reaction, take samples every 10 min to measure the phosphate concentration and the organophosphorus concentration, take a part of the reaction solution, add 1M NaOH, adjust the pH to 7, let it stand for precipitation, filter, and then measure the phosphate concentration and the organophosphorus concentration. Take another part of the filtered reaction solution, measure the total phosphorus content after high-temperature digestion, and calculate the total phosphorus removal rate.

[0046] The effects of the present invention are verified by the following tests: Test 1: This test is carried out for phosphorus removal under the conditions of Comparative Example 1, and the specific steps are as follows: At room temperature (25 °C), 17.9 mg / L of HMPA wastewater was introduced into a 1 L reaction vessel. Then, 200 mL of 1 g / L ferrous sulfate solution was added, and 1 M HClO4 was used to adjust the pH value to 3. The reaction vessel was connected to an ozone generator. The oxygen cylinder and ozone generator were turned on, and the flowmeter was adjusted to 2 L / min (the amount of ozone was 250 mg O3 / h per liter of water). The reaction system was operated to allow ozone to be evenly introduced into the reaction vessel. Every 10 min, 20 mL of the solution was taken and placed into a small beaker to measure the phosphate, organic phosphorus in the solution, and the phosphate and organic phosphorus in the precipitate. A rotor was added to the small beaker containing some of the solution, 1 M NaOH was added to adjust the pH value to 7, and it was stirred for 30 min and then left to stand for 1 h. After standing, the solution was filtered through a 0.22 μm filter membrane. 5 mL of the solution was taken to measure the phosphate, organic phosphorus in the solution, and the phosphate and organic phosphorus in the precipitate; another 5 mL of the solution was digested at high temperature to measure the total phosphorus content in the solution, and the total phosphorus removal rate was calculated.

[0047] Experiment 2: The phosphorus removal experiment was carried out under the conditions of Example 1, and the specific steps were as follows: At room temperature (25 °C), 17.9 mg / L of HMPA wastewater was introduced into a 1 L reaction vessel. Then, 20 mL of 1 g / L ferrous sulfate solution was added, and 1 M HClO4 was used to adjust the pH value to 3. The reaction vessel was connected to an ozone generator. The oxygen cylinder and ozone generator were turned on, and the flowmeter was adjusted to 2 L / min (the amount of ozone was 250 mg O3 / h per liter of water). The reaction system was operated to allow ozone to be evenly introduced into the reaction vessel. Every 10 min, 20 mL of the solution was taken and placed into a small beaker to measure the phosphate, organic phosphorus in the solution, and the phosphate and organic phosphorus in the precipitate, and 20 mL of 1 g / L ferrous sulfate solution was added again to the reaction vessel. A rotor was added to the small beaker containing some of the solution, 1 M NaOH was added to adjust the pH value to 7, and it was stirred for 30 min and then left to stand for 1 h. After standing, the solution was filtered through a 0.22 μm filter membrane. 5 mL of the solution was taken to measure the phosphate, organic phosphorus in the solution, and the phosphate and organic phosphorus in the precipitate; another 5 mL of the solution was digested at high temperature to measure the total phosphorus content in the solution, and the total phosphorus removal rate was calculated.

[0048] The organic phosphorus mineralization rate and total phosphorus removal rate of Experiment 1 and Experiment 2 are as Figure 2 and Figure 3 shown.

[0049] Figure 2It shows that after 100 minutes of reaction time, only 24.9% of phosphate can be generated by adding divalent iron at one time, while adding divalent iron step by step can mineralize 58.7% of HMPA, increasing the organic phosphorus mineralization rate by more than 30%. In addition, in the ozone oxidation system, by adding iron salts step by step, the organic phosphorus mineralization rate achieved by the fourth addition of divalent iron has reached the final organic phosphorus mineralization rate of adding divalent iron at one time, saving 70% of ozone consumption and 60% of iron addition amount, avoiding the waste of oxidants and reducing the iron addition cost.

[0050] Figure 3 It shows that after 100 minutes of reaction time, the total phosphorus removal rate of adding divalent iron step by step can reach 95%, among which 60% is phosphate precipitation and 35% is organic phosphorus precipitation, while adding divalent iron at one time can only precipitate 25% of phosphate and 3% of organic phosphorus. It can be seen that the total phosphorus removal rate of adding divalent iron step by step has increased by more than 65%. In addition to the fact that adding divalent iron step by step can increase the organic phosphorus mineralization rate, it can not only promote the combination of phosphate with Fe(III) formed by in-situ oxidation to generate FePO4 precipitation, but also enhance the formation of amorphous organic phosphorus-iron complex precipitation between organic phosphorus intermediate products and iron (hydro)oxides formed by iron hydrolysis. In addition, the organic phosphorus intermediate products entering the iron precipitate can also be quickly converted into inorganic phosphorus products by simple incineration, realizing the efficient enrichment and effective recovery of phosphorus.

Claims

1. A method for achieving the degradation of organophosphorus and recovering phosphorus in water in an ozone oxidation system, characterized in that: It includes the following steps: S1: Under room temperature conditions, add the wastewater containing organophosphorus compounds into a reaction vessel, then add a specific amount of catalyst, and adjust the pH value by adding acid. S2: Connect the reaction vessel to an ozone generator, open the oxygen cylinder and the ozone generator, adjust the flowmeter, and operate the reaction system to allow ozone to uniformly enter the reaction vessel. S3: Within a specific time period, sample and measure the phosphate ion concentration and organophosphorus concentration at time points with the same subsequent time intervals, and sequentially add the same amount of catalyst as in step S1 to the reaction vessel to achieve stepwise and multiple dosing of the catalyst. S4: After the reaction is completed, add alkali to the reaction vessel to adjust the pH value, stir, and let it stand for precipitation. S5: After the standing in step S4 is completed, filter and measure and calculate the phosphate ion concentration and organophosphorus concentration in the solution, as well as the phosphate ion concentration and organophosphorus concentration in the precipitate; take another part of the filtered reaction solution and measure the total phosphorus content in the solution.

2. The method for achieving the degradation of organophosphorus and the recovery of phosphorus in water in an ozone oxidation system according to claim 1, wherein: The catalyst is iron or an iron salt. The iron is zero-valent iron, including zero-valent iron powder or nano-zero-valent iron; the iron salt is a divalent iron salt solution or a trivalent iron salt solution. The divalent iron salt solution includes ferrous sulfate solution, ferrous chloride solution or ferrous nitrate solution, and the trivalent iron salt solution includes ferric sulfate solution, ferric chloride solution or ferric nitrate solution.

3. A method for achieving the degradation of organophosphorus and recovering phosphorus in water in an ozone oxidation system according to claim 1, characterized in that: The organophosphorus compounds include one of glyphosate, hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediamine tetramethylene phosphonic acid, hexamethylphosphoric triamide, hexamethylenediamine tetramethylene phosphonic acid and diethylenetriamine pentamethylene phosphonic acid.

4. A method for achieving the degradation of organophosphorus and the recovery of phosphorus in water in an ozone oxidation system according to claim 3, characterized in that: In step S1, the concentration of the organophosphorus compound is 10 - 20 mg / L; the pH value is adjusted to 2 - 4 by adding acid.

5. A method for achieving the degradation of organophosphorus and recovering phosphorus in water in an ozone oxidation system according to claim 2, characterized in that: The dosing times of the catalyst are 2 - 10 times, and the time intervals between adjacent dosings are equal.

6. A method for achieving the degradation of organophosphorus and the recovery of phosphorus in water in an ozone oxidation system according to claim 4, characterized in that: The amount of iron added each time is 0.5 - 1 g, or the volume of the added iron salt solution is 10 - 20 mL, and the concentration is 0.5 - 1 g / L.

7. A method for achieving the degradation of organophosphorus and the recovery of phosphorus in water in an ozone oxidation system according to claim 1, characterized in that: The process conditions of the ozone oxidation reaction include: the ozone dosage is 150 - 300 mg O3 / h per liter of water, the reaction pH value is 2 - 4, and the reaction temperature is room temperature.

8. A method for achieving the degradation of organophosphorus and recovering phosphorus in water in an ozone oxidation system according to claim 1, characterized in that: In step S3, the same time interval is every 5 - 10 min, and the specific time period is 60 - 100 min.

9. A method for achieving the degradation of organophosphorus and the recovery of phosphorus in water in an ozone oxidation system according to claim 1, characterized in that: In step S4, the added alkali is 0.6 - 1M sodium hydroxide solution, and the pH value is adjusted to 6 - 8.

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