Heterogeneous photo-Fenton method for high-selectivity oxidation treatment of organic phosphonate in water body

Abstract

The invention discloses a heterogeneous photo-Fenton method for high-selectivity oxidation treatment of organic phosphonate in a water body, and belongs to the technical field of water treatment. According to the invention, in a heterogeneous photo-Fenton reaction system composed of a photocatalyst, copper and H2O2, high-efficiency and high-selectivity oxidation of p-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) into orthophosphate is realized. According to the heterogeneous photo-Fenton reaction system disclosed by the invention, the degradation rate of HEDP can reach 97% within 6 minutes, and excellent reaction activity is shown. According to the method disclosed by the invention, the selective oxidation capacity on HEDP can still be kept in the presence of a coexisting competitive substrate. The catalyst provided by the invention has excellent recoverability and stability, and still keeps good activity after being recycled for multiple times, so that the environmental influence and the treatment cost are remarkably reduced, and the economic feasibility is enhanced. The method disclosed by the invention also shows certain universality, is suitable for various types of photocatalysts and different forms of copper, and shows higher orthophosphate yield.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and particularly relates to a heterogeneous photo-Fenton method for highly selective oxidation treatment of organic phosphonates in water. Background Art

[0002] With the acceleration of global industrialization and the continuous advancement of urbanization, water pollution problems are becoming increasingly serious, especially the impact of phosphorus-containing pollutants on water quality has attracted great attention in the field of environmental protection. Phosphorus is one of the elements necessary for biological growth, but excessive phosphorus can lead to eutrophication of water bodies, which in turn causes a series of environmental problems such as excessive algae reproduction and water quality deterioration. Therefore, effectively controlling and removing the phosphorus content in water has become an important topic in the current water treatment field. Among the many types of phosphorus-containing compounds, organic phosphonates have become a major challenge in the water treatment process due to their complex molecular structure and chemical properties. Unlike simple inorganic phosphates, organic phosphonates not only have strong complexing ability and can form stable complexes with a variety of metal ions, but are also widely used in industrial production processes as corrosion inhibitors, scale inhibitors, etc. The above characteristics make it difficult for organic phosphonates to be completely removed by traditional physical or chemical methods, and the precipitation or adsorption methods commonly used to remove inorganic phosphorus are also less effective in removing organic phosphonates.

[0003] Advanced Oxidation Processes (AOPs) are widely used in the production of reactive oxygen species, such as hydroxyl radicals (·OH), sulfate radicals (SO4 ·- ) and so on, and have been proven to have good removal effects on many difficult-to-degrade organic pollutants. These active oxygen species can gradually decompose complex organic molecules into smaller molecules through a non-selective oxidation process, until they are finally mineralized into carbon dioxide, water and inorganic salts. AOPs are not only suitable for the treatment of persistent organic pollutants in various industrial wastewaters, but also show potential application prospects for organic phosphonates. By adopting appropriate AOPs technology, such as systems based on persulfate (PMS) or hydrogen peroxide (H2O2), combined with photocatalysis or electrocatalysis, the decomposition of organic phosphonates can be effectively promoted. Xu, Wang et al. (Water Research. 2019, 148: 334-343) reported the use of high-dose ozone oxidation to treat 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), but only partial oxidation was achieved, and then more PBTC could be further removed by the calcium-phosphorus precipitate formed during the coagulation process. In the traditional Fenton reaction, hydrogen peroxide (H2O2) is used as an oxidant, and iron ions Fe 3+ / Fe 2+It acts as a catalyst, promoting the decomposition of hydrogen peroxide to produce hydroxyl radicals, which in turn oxidize phosphonates to phosphates (Water Research. 2017, 122: 345-354). However, the efficiency of the traditional Fenton reaction is not ideal. Even under conditions of a large excess of hydrogen peroxide, hydroxyl radicals can only achieve partial oxidation of phosphonates in a pure water environment (the conversion rate to phosphate is usually no more than 20%). Wang, Chen et al. (Water Research. 2019, 159: 30-37) reported a method for efficiently degrading aminotrimethylenephosphonic acid (NTMP) in water by ultraviolet light-activated persulfate, but when treating real reverse osmosis concentrates, due to Cl - and HCO3 - The presence of NTMP reduces the degradation efficiency of NTMP by 40%. At the same time, the traditional Fenton reaction also has the problem of potential iron sludge generation, which reduces the reaction efficiency and increases the treatment cost.

[0004] Therefore, the selective oxidation of phosphonates in complex water environments is particularly important. In recent years, studies have used the strong coordination between phosphonates and metals to achieve selective oxidation of phosphonates through the electron transfer mechanism from ligand to metal. For example, Zhu et al. (Water Research. 2021, 202, 117397) oxidized the phosphonate HEDP (hydroxyethylidene diphosphonic acid) by the Co (II)-PMS process. They used the coordination of HEDP with the Co (II)-PMS complex to oxidize HEDP through a single electron transfer or oxygen atom transfer mechanism. Sun et al. (Environ. Sci. Technol. 2022, 56, 634-641) used the Cu (II)-H2O2 process under alkaline conditions to utilize the coordination of phosphonates and copper to achieve selective oxidation of HEDP through intramolecular electron transfer. However, all of the above methods are reactions of homogeneous systems, and the catalyst (metal ions) are evenly dispersed in the solution. In this case, although the reaction efficiency may be high, there are problems with the recovery and reuse of the catalyst, which not only increases the processing cost, but also may cause secondary pollution caused by residual metal ions. Summary of the invention

[0005] In order to improve the above technical problems, the present invention provides a heterogeneous photo-Fenton method for highly selective oxidation treatment of organic phosphonates in water. The present invention utilizes the synergistic coordination of photocatalysis-Fenton-metal and phosphonic acid to achieve the conversion of organic phosphonate pollutants to orthophosphates in a simple and mild system. The heterogeneous photo-Fenton method of the present invention can achieve nearly 97% oxidation conversion of organic phosphonates into orthophosphates within 6 minutes, and at the same time has high anti-interference performance against common anions and organic matter in the environment. The heterogeneous photo-Fenton method of the present invention can use simulated sunlight and relatively environmentally friendly H2O2 under mild conditions to perform efficient and highly selective conversion of phosphonates.

[0006] To achieve the above object, the present invention provides a heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water, comprising subjecting the phosphonates to a photocatalytic reaction in a system consisting of a photocatalyst, copper and H2O2.

[0007] According to an embodiment of the present invention, the copper may be present in the reaction system in the form of copper ions or copper nanoparticles. Preferably, the copper may be present in the reaction system in the form of copper nanoparticles supported on a photocatalyst and / or in the form of divalent copper ions (e.g., copper salts).

[0008] According to an embodiment of the present invention, the photocatalyst may be a common semiconductor photocatalyst (commercially available or synthesized). For example, the semiconductor photocatalyst is selected from at least one of TiO2, ZnO, CdS, WO3, SrTiO3, BiVO4, ZnInS4 and g-C3N4, preferably at least one of g-C3N4, WO3 and BiVO4.

[0009] In one embodiment of the present invention, the photocatalyst is loaded with copper nanoparticles. For example, the loading of the copper nanoparticles is carried out by a photocatalyst and a copper salt through a photodeposition method. For example, the photocatalyst and the copper salt are dissolved in a solvent (such as water) to obtain a suspension, and then a photocatalyst loaded with copper nanoparticles is obtained through a photodeposition method.

[0010] In one embodiment of the present invention, the photodeposition method further comprises solid-liquid separation, washing and drying of the reaction liquid.

[0011] In one embodiment of the present invention, the mass ratio of the copper salt to the photocatalyst is (0.005-0.02):1, exemplified by 0.005:1, 0.008:1, 0.01:1, 0.015:1 or 0.02:1.

[0012] In one embodiment of the present invention, the copper salt is, for example, copper nitrate trihydrate.

[0013] In one embodiment of the present invention, the wavelength of the light deposition method is 190nm to 1100nm after the wavelength of the emission of a 300W xenon lamp is filtered through a filter; 420 to 1100nm is exemplary; the light intensity of the light deposition method is preferably 100mW / cm 2 ~1000mW / cm 2 , exemplified by 100 mW / cm 2 ; The time of the photodeposition method is 1 to 10 hours, preferably 1 to 5 hours, and exemplarily 2 hours.

[0014] According to an embodiment of the present invention, the heterogeneous photo-Fenton method for oxidatively treating organic phosphonates in water comprises the following steps:

[0015] Step 1: mixing a photocatalyst loaded with copper nanoparticles with H2O2 and a phosphonate solution to obtain a reaction solution;

[0016] or mixing the photocatalyst, copper salt, H2O2 and phosphonate solution to obtain a reaction solution;

[0017] Step 2: subjecting the reaction solution to a photocatalytic reaction.

[0018] According to an embodiment of the present invention, the light source used in the photocatalytic reaction is provided by a xenon lamp, an LED lamp or other equipment capable of providing illumination, preferably a xenon lamp.

[0019] According to the embodiment of the present invention, the wavelength range of the light emitted by the light source is 190nm~1200nm; the light intensity range is 100mW / cm 2 ~1000mW / cm 2 , exemplified by 100 mW / cm 2 .

[0020] According to an embodiment of the present invention, in step 2, the reaction is carried out in an air environment.

[0021] According to an embodiment of the present invention, in step 2, the reaction is carried out under stirring conditions.

[0022] According to an embodiment of the present invention, in step 2, the reaction temperature is 20-60°C, exemplified by 20°C, 30°C, 40°C, 50°C or 60°C.

[0023] According to an embodiment of the present invention, in step 2, the reaction time is 1 to 30 min, exemplified by 1 min, 2 min, 5 min, 6 min, 8 min, 10 min 15 min, 20 min or 30 min.

[0024] According to an embodiment of the present invention, the photocatalytic reaction includes oxidative degradation of phosphonates into inorganic phosphorus.

[0025] According to an embodiment of the present invention, the phosphonate is a phosphorus-containing organic compound in which a phosphorus atom is directly connected to one or more carbon atoms, preferably comprising one or more phosphonic acid groups (-PO3H2 or its salt form), and more preferably at least one of the following phosphonates containing 1-5 phosphonic acid groups: 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylenephosphonic acid (NTMP), ethylenediaminetetramethylenephosphonic acid (EDTMP) and diethylenetriaminepentamethylenephosphonic acid (DTPMP).

[0026] According to an embodiment of the present invention, the inorganic phosphorus product is a phosphorus compound without a carbon-phosphorus bond, preferably orthophosphate.

[0027] According to an embodiment of the present invention, the photocatalyst feed concentration is 0.25-5 g / L, preferably 0.5-2 g / L, and exemplified by 0.25 g / L, 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L.

[0028] According to an embodiment of the present invention, copper is present in the reaction system in the form of copper ions (e.g., copper salts), and the copper ion feed concentration is 2.5 to 50 mg / L, preferably 5 to 20 g / L, and exemplified by 2.5 g / L, 5 g / L, 8 g / L, 10 g / L, 15 g / L, 20 g / L, 30 g / L, 40 g / L or 50 mg / L.

[0029] According to an embodiment of the present invention, the feeding concentration of H2O2 is 0.1-10 mol / L, preferably 0.5-5 g / L, and exemplified by 0.1 g / L, 0.2 g / L, 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L, 2 mol / L, 3 g / L, 4 g / L, 5 g / L, 8 g / L or 10 g / L.

[0030] In the present invention, the feed concentration refers to the concentration of a substance in the reaction solution.

[0031] According to an embodiment of the present invention, the concentration of the phosphonate in the reaction solution is 0.01 to 10 mol / L, preferably 0.5 to 5 mol / L, and exemplified by 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 8 mol / L or 10 mol / L.

[0032] According to an embodiment of the present invention, after the reaction in step 2, the following steps are further included: collecting the reaction solution, adding a color developer, and analyzing the phosphate concentration by a UV-visible spectrophotometer.

[0033] According to an embodiment of the present invention, after collecting the reaction liquid, the following steps may be further included: solid-liquid separation and recovery of the photocatalyst.

[0034] In one embodiment of the present invention, the solid-liquid separation can be carried out by known means in the art, such as centrifugation. Preferably, the centrifugal speed is 6000-10000rpm, such as 7000-9000rpm, exemplified by 6000rpm, 7000rpm, 8000rpm, 9000rpm or 10000rpm. Further, the centrifugal time is 3-10min, such as 5-8min, exemplified by 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min.

[0035] The present invention also provides application of the method in catalytic oxidation degradation of water containing organic phosphonate pollutants.

[0036] Beneficial effects of the present invention:

[0037] (1) The present invention utilizes the coordination effect of photocatalysis-Fenton-metal and phosphonic acid to achieve efficient and highly selective oxidation of phosphate. At the same time, the present invention utilizes the electron-hole pairs generated by the photocatalyst under light conditions and the ability to catalyze hydrogen peroxide (H2O2) to generate active oxygen species with strong oxidizing properties (such as hydroxyl radicals (·OH)). At the same time, the coordination effect of copper and phosphonate also enhances its anti-interference performance in complex environments, achieving selective oxidation of phosphonate. In the present invention, the yield of phosphate can reach up to 97%, and even in the presence of common anions and organic matter, it can still guarantee a conversion rate of more than 85%.

[0038] (2) The reaction conditions of the present invention are controllable and mild. Under the best condition, only 2 minutes are required to achieve a phosphate conversion rate of about 84%, and 6 minutes is required to achieve a conversion rate of 97%, which is much higher than the currently reported phosphate conversion rate.

[0039] (3) The photocatalyst used in the present invention is stable and easy to recover and reuse after the reaction, which can effectively reduce the reaction cost. At the same time, the present invention uses H2O2 as an oxidant, which will not cause secondary pollution to the environment during use, thereby reducing the environmental burden.

[0040] (4) The copper in the catalyst used in the present invention exists in various forms, and has high reaction activity whether it is dispersed in the solution as copper ions or loaded on the photocatalyst.

[0041] (5) The present invention can be used as a universal method, and is not limited to a specific photocatalyst. Commercially available catalysts can be directly used without special improvements to the catalysts, thus effectively simplifying the production process and reducing production costs. Compared with the prior art, the present invention eliminates the problem of iron sludge generation, and due to the reusability of the catalyst, significantly reduces environmental impact and processing costs, and enhances economic feasibility. The simplified operating procedures and improved work efficiency of the present invention make the present invention more suitable for industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a graph showing the conversion of HEDP to orthophosphate by Cu / BiVO4-H2O2 in Example 2 of the present invention over time.

[0043] Figure 2 This is the effect of the presence or absence of coexisting pollutants on the performance of Cu / BiVO4-H2O2 in efficiently oxidizing HEDP to orthophosphate in Examples 2-6 of the present invention.

[0044] Figure 3 The performance stability of the system after the Cu / BiVO4 is recovered and reacted again in Example 7 of the present invention.

[0045] Figure 4 The performance of oxidizing HEDP to orthophosphate in Example 8, Example 10 and Comparative Example 2.

[0046] Figure 5 The g-C3N4, WO3, and BiVO4 in the pure copper-based Fenton reaction (Cu 2+ -H2O2), photocatalysis and heterogeneous photo-Fenton reaction (photocatalyst-Cu 2+ -H2O2) effect.

[0047] Figure 6 The effects of different reaction conditions on the formation of orthophosphate in Example 2 and Comparative Examples 4-7 are shown. DETAILED DESCRIPTION

[0048] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0049] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0050] Example 1

[0051] The method of loading copper in the form of nanoparticles on the photocatalyst is a photodeposition method, which includes the following steps:

[0052] (1) Weigh 19 mg of copper nitrate trihydrate and 0.5 g of bismuth vanadate photocatalyst, place them in 100 mL of deionized water, stir them evenly, and then place the mixed suspension into a quartz photoreactor.

[0053] Wherein: the preparation method of bismuth vanadate photocatalyst comprises the following steps:

[0054] (a) 0.585 g of ammonium metavanadate and 2.425 g of bismuth nitrate pentahydrate were weighed and placed in 20 mL of 4 mol / L nitric acid solution, and stirred at room temperature for 0.5 h to obtain a light yellow, clear mixed nitric acid solution of ammonium metavanadate and bismuth nitrate.

[0055] (b) 25 mL of saturated sodium carbonate solution was added to the obtained mixed nitric acid solution to adjust the pH value of the solution to 5.0 to form a yellow slurry, which was stirred at room temperature for 0.5 h.

[0056] (c) The obtained yellow slurry was transferred to a 20 mL stainless steel autoclave with a Teflon lining and subjected to hydrothermal treatment at 180° C. for 2 h. After the autoclave was cooled to room temperature, the suspension was filtered, washed three times with deionized water, and then dried in vacuum at 60° C. to obtain a yellow bismuth vanadate photocatalyst.

[0057] (2) Place the quartz photoreactor under a 300W xenon lamp (wavelength range 420nm-1200nm, light intensity 100mW / cm 2 ) for 2 h, the suspension was filtered, washed three times with deionized water, and then dried in vacuum at 60 °C to obtain a photocatalyst loaded with copper nanoparticles.

[0058] Example 2

[0059] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution and 20 mL of 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 The reaction was continued for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane, and the active species in the reaction were quenched with 50 μL of Na2SO3 (0.5 M) before analysis.

[0060] The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. 100 μL of ascorbic acid (100 g / L) and 200 μL of ammonium molybdate solution (26.0 g / L ammonium molybdate tetrahydrate, 0.7 g / L potassium antimony tartrate and 5.0 M sulfuric acid) were added to the test solution (the test solution includes unreacted HEDP substrate and phosphate products generated after the reaction, and the concentration of each component varies with the time of taking out the reaction solution). After waiting for 15 minutes for color development, the absorbance was measured at a wavelength of 710 nm using a UV / visible spectrophotometer. Finally, the concentration of orthophosphate was calculated using the standard curve method.

[0061] See also Figure 1 It can be seen that the phosphate generation rate (i.e., the degradation rate of HEDP) reaches more than 80% only 2 minutes after the reaction starts, and the phosphate generation rate reaches 97% after 6 minutes of reaction. This shows that the present invention utilizes the electron-hole pairs generated by the photocatalyst under light conditions and the ability to catalyze hydrogen peroxide (H2O2) to generate active oxygen species (hydroxyl radicals (·OH)) with strong oxidizing properties, and utilizes the coordination effect of photocatalysis-Fenton-metal and phosphonic acid to achieve efficient and highly selective oxidation of phosphonates.

[0062] Example 3

[0063] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution, 11.69 mg of sodium chloride and 20 mL of 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 . The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate after the reaction in the system under the influence of high concentrations of chloride ions was calculated using the standard curve method. See Figure 2 It can be seen that under the influence of high concentration of chloride ions, the phosphate generation rate after the reaction is still as high as 94.6%.

[0064] Example 4

[0065] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution, 28.41 mg of sodium sulfate and 20 mL of 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 . The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate after the reaction in the system under the influence of high concentrations of sulfate ions was calculated using the standard curve method. See Figure 2 It can be seen that under the influence of high concentration of sulfate ions, the phosphate generation rate after the reaction is still as high as 93.2%.

[0066] Example 5

[0067] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution, 16.8 mg of sodium bicarbonate and 20 mL of 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 . The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate after the system reacted under the influence of high concentrations of bicarbonate ions was calculated using the standard curve method. See Figure 2 It can be seen that the phosphate generation rate after the reaction under the influence of high concentration of bicarbonate ions is as high as 87.7%.

[0068] Example 6

[0069] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution, 0.2 mg of natural organic matter (NOM, sodium humate (purchased from Beijing Inokai Technology Co., Ltd., brand name Thermo scientific, item number 120861000) was used as a representative in the reaction) and 20 mL of 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 . The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane, and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate in the system after the reaction under the influence of high concentration of sodium humate was calculated using the standard curve method. See Figure 2 It can be seen that the phosphate generation rate after the reaction is as high as 86.2% under the influence of high concentration of sodium humate.

[0070] Example 7

[0071] 20 mg of Cu / BiVO4 prepared in Example 1, 13.6 mg of 10% H2O2 solution and 20 mL of 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C. The reaction light source was a 300 W xenon lamp equipped with an AM1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min under uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. After the reaction was completed, the used photocatalyst was collected by high-speed centrifugation at 8000 rpm for 10 min, washed with deionized water, dried, and then added to the new reaction solution for the next reaction. Figure 3 It can be seen that after five cycles, the degradation rate of HEDP only slightly decreased from 97% to 93.6%, indicating that the reaction system is stable.

[0072] Example 8

[0073] The preparation method of Cu / WO3 is as follows:

[0074] (1) Weigh 19 mg of copper nitrate trihydrate and 0.5 g of WO3 (purchased from Aladdin Reagent Co., Ltd., brand: Aladdin, item number: T103857-25g), place in 100 mL of deionized water, stir evenly and place the mixed suspension into a quartz photoreactor.

[0075] (2) Place the quartz photoreactor under a 300W xenon lamp (wavelength range 420nm-1200nm, light intensity 100mW / cm 2 ) for 2 h, the suspension was filtered, washed three times with deionized water, and then dried in vacuum at 60 °C to obtain a photocatalyst Cu / WO3 loaded with copper nanoparticles.

[0076] 20 mg Cu / WO3, 13.6 mg 10% H2O2 solution and 20 mL 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 4 It can be seen that after the photocatalyst is replaced with WO3, the phosphate generation rate after the reaction can reach 67.4%.

[0077] Example 9

[0078] 40 g of urea was placed in a covered crucible and heated to 550 °C at a heating rate of 2 °C / min and calcined for 2 h to obtain a g-C3N4 catalyst.

[0079] 20 mg g-C3N4, 0.76 mg copper nitrate trihydrate, 13.6 mg 10% H2O2 solution and 20 mL 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5It can be seen that the phosphate generation rate is as high as 68.7%.

[0080] Example 10

[0081] 20 mg WO3, 0.76 mg copper nitrate trihydrate, 13.6 mg 10% H2O2 solution and 20 mL 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5 It can be seen that the phosphate generation rate is as high as 77.4%.

[0082] Embodiment 11

[0083] 20 mg BiVO4, 0.76 mg copper nitrate trihydrate, 13.6 mg 10% H2O2 solution and 20 mL 0.1 mM HEDP aqueous solution were added into a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5 It can be seen that the phosphate generation rate is as high as 75.6%.

[0084] Comparative Example 1

[0085] 20 mg BiVO4 and 20 mL 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5 It can be seen that the phosphate generation rate is only 38%.

[0086] Comparative Example 2

[0087] 20 mg WO3 and 20 mL 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5 It can be seen that the phosphate generation rate is only 6.4%.

[0088] Comparative Example 3

[0089] 20 mg g-C3N4 and 20 mL 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 5 It can be seen that the phosphate generation rate is only 6%.

[0090] Comparative Example 4

[0091] 20 mg BiVO4, 0.76 mg copper nitrate trihydrate and 20 mL 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter and was 100 mW cm -2The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 6 (Cu / BiVO4 illumination) It can be seen that the phosphate generation rate is only 59%.

[0092] Comparative Example 5

[0093] 0.76 mg of copper nitrate trihydrate, 13.6 mg of 10% H2O2 and 20 mL of 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 6 (Cu 2+ -H2O2 illumination), the phosphate generation rate was only 4.3%.

[0094] Comparative Example 6

[0095] 20mg Cu / BiVO4, 13.6mg 10% H2O2 solution and 20mL 0.1mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30°C and no external reaction light source was added. The reaction was allowed to proceed for 15min with uniform stirring. At given time intervals, 1mL of the reaction solution was filtered with a 0.22μm filter membrane and 50μL Na2SO3 (0.5M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. See Figure 6 (Cu / BiVO4-H2O2 without light) It can be seen that the phosphate generation rate is only 7.8%.

[0096] Comparative Example 7

[0097] 0.76 mg of copper nitrate trihydrate and 20 mL of 0.1 mM HEDP aqueous solution were added to a quartz container equipped with a water circulation interlayer. The water circulation temperature was maintained at 30 °C. The reaction light source was a 300 W xenon lamp equipped with an AM 1.5G filter. The light intensity was measured by a light intensity meter to be 100 mW cm -2 The reaction was allowed to proceed for 15 min with uniform stirring. At given time intervals, 1 mL of the reaction solution was filtered with a 0.22 μm filter membrane and 50 μL of Na2SO3 (0.5 M) was used to quench the active species in the reaction before analysis. The formation of orthophosphate in the reaction was detected by ammonium molybdate spectrophotometry. Finally, the concentration of orthophosphate was calculated using the standard curve method. Figure 6 It can be seen that no phosphate is generated.

[0098] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water, characterized in that: The method comprises placing phosphonate in a system consisting of a photocatalyst, copper and H2O2 to perform a photocatalytic reaction.

2. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to claim 1, characterized in that: The copper exists in the reaction system in the form of copper ions or copper nanoparticles. Preferably, the copper exists in the form of copper nanoparticles supported on the photocatalyst and / or exists in the reaction system in the form of divalent copper ions (such as copper salt). Preferably, the photocatalyst is selected from at least one of TiO2, ZnO, CdS, WO3, SrTiO3, BiVO4, ZnInS4 and g-C3N4.

3. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to claim 2, characterized in that: The photocatalyst is loaded with copper nanoparticles. Preferably, the copper nanoparticles are loaded by photocatalyst and copper salt through a photodeposition method.

4. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to claim 3, characterized in that: The photocatalyst and copper salt are dissolved in a solvent to obtain a suspension, and a photocatalyst loaded with copper nanoparticles is obtained through a photodeposition method. Preferably, the mass ratio of the copper salt to the photocatalyst is (0.005-0.02):

1. Preferably, the copper salt is copper nitrate trihydrate.

5. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: mixing a photocatalyst loaded with copper nanoparticles with H2O2 and a phosphonate solution to obtain a reaction solution; or mixing the photocatalyst, copper salt, H2O2 and phosphonate solution to obtain a reaction solution; Step 2: subjecting the reaction solution to a photocatalytic reaction.

6. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to any one of claims 1 to 5, characterized in that: The reaction temperature is 20-60° C., and the reaction time is 1-30 min.

7. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to any one of claims 1 to 6, characterized in that: The phosphonate is at least one of the following phosphonates containing 1 to 5 phosphonic acid groups: 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylenephosphonic acid (NTMP), ethylenediaminetetramethylenephosphonic acid (EDTMP) and diethylenetriaminepentamethylenephosphonic acid (DTPMP).

8. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to any one of claims 1 to 7, characterized in that: The feed concentration of the photocatalyst is 0.25 to 5 g / L, preferably 0.5 to 2 g / L. Preferably, copper exists in the reaction system in the form of copper ions, and the feed concentration of copper ions is 2.5 to 50 mg / L. Preferably, the feed concentration of H2O2 is 0.1-10 mol / L.

9. The heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water according to any one of claims 1 to 8, characterized in that: The concentration of the phosphonate in the reaction solution is 0.01-10 mol / L.

10. Use of the heterogeneous photo-Fenton method for oxidative treatment of organic phosphonates in water bodies as described in any one of claims 1 to 9 in catalytic oxidation degradation of water bodies containing organic phosphonate pollutants.

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