A porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, its preparation method, and its application in water phosphorus removal

Abstract

The present invention discloses a porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, a preparation method thereof, and an application thereof in water phosphorus removal. The preparation method of the composite material comprises the following steps: (1) adding WO3 powder to deionized water to obtain WO3 dispersion A; (2) dissolving porphyrin in an organic solvent to obtain porphyrin solution B; (3) adding porphyrin solution B to WO3 dispersion A under stirring conditions, then ultrasonically dispersing the porphyrin, and stirring to obtain porphyrin-loaded WO3 solution C; (4) adding an iron salt to the porphyrin-loaded WO3 solution C to obtain a mixed solution D; (5) adding a reducing agent to the mixed solution D, then stirring, and then centrifuging, and washing, drying, and grinding the precipitate obtained by centrifugation. The present invention is superior to existing technologies in terms of phosphorus removal efficiency, multifunctional processing capacity, material selectivity, environmental friendliness, and industrialization potential, and has significant application prospects and market competitiveness.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and in particular to a porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, a preparation method thereof, and application thereof in phosphorus removal in water bodies. Background Art

[0002] With the development of agriculture and industry, as well as the discharge of domestic sewage, phosphorus concentrations in water bodies have gradually increased, exacerbating the problem of eutrophication. The algal blooms and algae outbreaks caused by eutrophication not only damage aquatic ecosystems, but also seriously affect water resource utilization and even threaten human health. Therefore, controlling phosphorus pollution in water bodies has become a research priority in the field of environmental protection.

[0003] At present, the methods for removing phosphorus from water bodies mainly include chemical precipitation, biological dephosphorization and adsorption. Among them, the adsorption method has become a research hotspot due to its simple operation, low cost and environmental friendliness. Tungsten trioxide (WO3), as a transition metal oxide, has broad application prospects in the field of environmental remediation due to its unique electronic structure and excellent catalytic properties. However, the use of tungsten trioxide alone in water treatment shows certain limitations, such as low activity and limited adsorption capacity. To overcome these shortcomings, researchers have tried to combine tungsten trioxide with other functional materials to improve its performance, but so far, no composite method that can effectively improve the adsorption capacity has been developed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a porphyrin and zero-valent iron co-loaded tungsten trioxide composite material with selective adsorption capacity for phosphate and higher phosphorus removal efficiency, as well as a preparation method and application thereof.

[0005] To achieve the above object, the present invention provides a method for preparing a porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, comprising the following steps:

[0006] (1) WO3 powder was added to deionized water, which was then purged with nitrogen to remove dissolved oxygen, and then subjected to ultrasonic dispersion treatment to obtain WO3 dispersion A;

[0007] (2) dissolving porphyrin in an organic solvent to obtain a porphyrin solution B;

[0008] (3) adding the porphyrin solution B to the WO3 dispersion A under stirring conditions, then performing ultrasonic dispersion treatment, and then stirring to obtain a porphyrin-loaded WO3 solution C;

[0009] (4) adding iron salt to the porphyrin-loaded WO3 solution C, and then stirring to obtain a mixed solution D;

[0010] (5) Adding a reducing agent to the mixed solution D, stirring the solution, and then centrifuging the solution. Washing, drying, and grinding the precipitate obtained by centrifugation to obtain the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material.

[0011] Furthermore, in step (1), the material-liquid ratio of the WO3 powder to deionized water is 0.5-3 g: 100-500 mL.

[0012] Furthermore, in step (2), the organic solvent is any one of ethanol, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide or tetrahydrofuran, or a mixture of two or more thereof in any proportion; the porphyrin is any one of iron porphyrin, zinc porphyrin, cobalt porphyrin or nickel porphyrin, or a mixture of two or more thereof in any proportion, and the solid-liquid ratio of the porphyrin to the organic solvent is 0.05-2 g:50-500 mL.

[0013] Furthermore, in step (3), the dosage ratio of the WO3 dispersion A and the porphyrin solution B is: based on the porphyrin and WO3 powder contained, the mass ratio of porphyrin to WO3 powder is 0.1-0.2:1-1.5.

[0014] Furthermore, in step (4), the iron salt is any one of FeSO4, FeCl3 or Fe(NO3)3, or a mixture of two or more thereof in any proportion, and the dosage ratio of the iron salt and porphyrin-loaded WO3 solution C is: based on the iron element contained and the WO3 powder, the mass ratio of the iron element to the WO3 powder is 0.1-15g:0.5-30g.

[0015] Furthermore, in step (5), the reducing agent is any one of sodium borohydride, potassium borohydride, vitamin C, hydroxylamine hydrochloride, tea polyphenols, and ascorbic acid, or a mixture of two or more thereof in any proportion, and the mass ratio of the reducing agent to the iron salt is 0.1-5 g:0.1-10 g.

[0016] The present invention also provides a porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, which is prepared according to the above preparation method.

[0017] The present invention also provides the use of the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material in phosphorus removal from water.

[0018] The present invention also provides a method for removing phosphate from water, comprising the following steps: adding the above-mentioned porphyrin and zero-valent iron co-loaded tungsten trioxide composite material to a phosphate-containing water body, and stirring the reaction at room temperature.

[0019] Furthermore, the phosphate concentration of the water body is controlled at 0.1-100 mg / L, the dosage of the composite material is 0.1-5.0 g / L, the reaction conditions are pH 5-10, stirring speed 50-300 r / min, and reaction time 30-120 min.

[0020] The composite material of the present invention is composed of porphyrin, zero-valent iron and WO3. During preparation, the porphyrin molecules are first loaded on the WO3 surface through physical adsorption (such as van der Waals force, π-π interaction) and chemical adsorption (such as coordination bond). The metal ions in the porphyrin molecules may combine with the oxygen atoms on the WO3 surface through coordination to form a stable composite structure. Subsequently, Fe 0 The particles were deposited on porphyrin-supported WO3 via a reduction reaction.

[0021] Zero valent iron (Fe 0 ) has high redox capacity. In water environment, Fe 0 It is easy to react with dissolved oxygen or water molecules in water to produce ferrous ions (Fe 2+ ) and ferric ions (Fe 3+ ). The generated Fe 2+ and Fe 3+ Further with phosphate (PO4 3- ) reacts to form an insoluble iron-phosphorus compound (FePO4). 2+ Fe formed after oxidation 3+ It can also continue to react with phosphates to further enhance the phosphorus removal effect.

[0022] Porphyrin is a macrocyclic conjugated compound with excellent electron transfer properties and certain adsorption capacity. Porphyrin can accelerate the Fe 0 Oxidized to Fe 2+ / Fe 3+ reaction, thereby improving the precipitation efficiency of phosphate. In addition, the special macrocyclic structure of porphyrin enables the material to effectively identify and capture phosphate ions in water, avoiding the interference of other competitive ions, thereby enhancing the phosphorus removal effect. In addition, the rich π electron system in porphyrin can participate in the electron transfer process, enhance the overall reaction activity of the composite material, accelerate the decomposition of inorganic phosphorus, and thus achieve a more accurate phosphorus removal effect. The composite material of the present invention combines the adsorption effect of WO3, the electron transfer performance of porphyrin and Fe 0 The reducing ability of the material and the synergistic effect of the various components significantly improve the selective adsorption capacity of the material for phosphate, avoiding the interference of other competitive ions, thereby achieving a more accurate phosphorus removal effect, and greatly improving the phosphorus removal efficiency, achieving efficient removal of phosphate. This advantage is particularly significant in the treatment of high-phosphorus polluted water bodies.

[0023] The beneficial effects of the present invention are embodied in:

[0024] 1. By combining porphyrin, Fe 0 When combined with WO3, the material of the present invention exhibits a significant synergistic effect in phosphorus removal. Compared with a single material, the composite material of the present invention can achieve efficient phosphorus removal under various water quality conditions.

[0025] 2. Fe used in the present invention 0 Both WO3 and WO3 are inexpensive and readily available materials, and their preparation process is relatively simple, requiring no complex processes or expensive equipment. Therefore, this material is economically viable for large-scale applications. Furthermore, its use does not generate secondary pollution, meeting environmental requirements and being more environmentally friendly than some existing chemical treatment methods.

[0026] 3. The preparation process of the present invention is simple, allowing for easy scalable production. Furthermore, the material design takes into account operational convenience in actual water treatment processes. Therefore, the material has great potential for industrial application and can be easily integrated into existing water treatment systems, enabling rapid technology adoption.

[0027] In summary, the present invention is superior to existing technologies in terms of phosphorus removal efficiency, multifunctional treatment capacity, material selectivity, environmental friendliness and industrialization potential, and provides a scientific basis and practical method for the effective treatment of phosphorus pollution (such as sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate) in water bodies (such as network sewage, rural sewage, tap water, river water, lake water, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The Por-Fe prepared in Example 4 of the present invention 0 Transmission electron microscopy (TEM) image of @WO3-4.

[0029] Figure 2 The Por-Fe prepared in Example 4 of the present invention 0 @WO3-4 X-ray diffraction pattern (XRD). DETAILED DESCRIPTION

[0030] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0031] Unless otherwise specified, the raw materials, reagents, and apparatus used in the following examples can be obtained from conventional commercial sources or by known methods. Unless otherwise specified, the methods used in the examples are all within the skill of those skilled in the art. Ultrasonic dispersion was performed using an FS-450N Ultrasonic Material Disperser.

[0032] Example 1

[0033] Preparation of porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0034] The preparation method is as follows:

[0035] Step (1): 1 g of WO3 powder was dissolved in 200 mL of deionized water, purged with nitrogen for 30 min to remove dissolved oxygen, and ultrasonically dispersed for 1 h to ensure that the oxidized WO3 was fully dispersed in the solution to form a uniform WO3 dispersion A;

[0036] Step (2): dissolving 0.1 g of bis(tetrakis-p-chlorophenyl)iron porphyrin in 50 mL of ethanol and stirring the mixture to form porphyrin solution B;

[0037] Step (3): under stirring conditions, slowly dropwise add the porphyrin solution B to the WO3 dispersion A, ultrasonically disperse for 30 min, and then stir at a speed of 150 r / min for 3 h to form a porphyrin-loaded WO3 solution C;

[0038] Step (4): adding 0.5 g of ferrous sulfate to the porphyrin-loaded WO3 solution C, and then stirring at a speed of 200 r / min for 1 h to ensure that the iron salt is fully dissolved, to obtain a mixed solution D;

[0039] Step (5): 0.5 g of sodium borohydride was slowly added to the mixed solution D, and then stirred at a speed of 250 r / min for 2 h to deposit Fe 0 The particles are loaded with porphyrin on the surface of WO3, and finally centrifuged. The precipitate obtained by centrifugation is washed with deionized water, dried in a vacuum drying oven at 60°C, and then ground to obtain a composite material of porphyrin and zero-valent iron loaded with tungsten trioxide. Labeled as Por-Fe 0 @WO3-1, porphyrin, Fe 0 The mass ratio of WO3 is 0.1g:0.184g:1g.

[0040] Example 2

[0041] Preparation of porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0042] The preparation method is as follows:

[0043] Step (1): 1.5 g of WO3 powder was dissolved in 200 mL of deionized water, purged with nitrogen for 30 min to remove dissolved oxygen, and ultrasonically dispersed for 1 h to ensure that the oxidized WO3 was fully dispersed in the solution to form a uniform WO3 dispersion A;

[0044] Step (2): dissolving 0.1 g of bis(tetrakis-p-chlorophenyl)iron porphyrin in 50 mL of ethanol and stirring the mixture to form porphyrin solution B;

[0045] Step (3): under stirring conditions, slowly dropwise add the porphyrin solution B to the WO3 dispersion A, ultrasonically disperse for 30 min, and then stir at a speed of 150 r / min for 3 h to form a porphyrin-loaded WO3 solution C;

[0046] Step (4): adding 0.5 g of ferrous sulfate to the porphyrin-loaded WO3 solution C, and then stirring at a speed of 200 r / min for 1 h to ensure that the iron salt is fully dissolved, to obtain a mixed solution D;

[0047] Step (5): 0.5 g of sodium borohydride was slowly added to the mixed solution D, and then stirred at a speed of 250 r / min for 2 h to deposit Fe 0 The particles are loaded with porphyrin on the surface of WO3, and finally centrifuged. The precipitate obtained by centrifugation is washed with deionized water, dried in a vacuum drying oven at 60°C, and then ground to obtain a composite material of porphyrin and zero-valent iron loaded with tungsten trioxide. Labeled as Por-Fe 0 @WO3-2, porphyrin, Fe 0 The mass ratio of WO3 is 0.1g:0.184g:1.5g.

[0048] Example 3

[0049] Preparation of porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0050] The preparation method is as follows:

[0051] Step (1): 1 g of WO3 powder was dissolved in 200 mL of deionized water, purged with nitrogen for 30 min to remove dissolved oxygen, and ultrasonically dispersed for 1 h to ensure that the oxidized WO3 was fully dispersed in the solution to form a uniform WO3 dispersion A;

[0052] Step (2): dissolving 0.2 g of bis(tetrakis-p-chlorophenyl)iron porphyrin in 100 mL of ethanol and stirring the mixture to form porphyrin solution B;

[0053] Step (3): under stirring conditions, slowly dropwise add the porphyrin solution B to the WO3 dispersion A, ultrasonically disperse for 30 min, and then stir at a speed of 150 r / min for 3 h to form a porphyrin-loaded WO3 solution C;

[0054] Step (4): adding about 0.5 g of ferrous sulfate to the porphyrin-loaded WO3 solution C, and then stirring at a speed of 200 r / min for 1 h to ensure that the iron salt is fully dissolved, to obtain a mixed solution D;

[0055] Step (5): 0.5 g of sodium borohydride was slowly added to the mixed solution D, and then stirred at a speed of 250 r / min for 2 h to deposit Fe 0The particles are loaded with porphyrin on the surface of WO3, and finally centrifuged. The precipitate obtained by centrifugation is washed with deionized water, dried in a vacuum drying oven at 60°C, and then ground to obtain a composite material of porphyrin and zero-valent iron loaded with tungsten trioxide. Labeled as Por-Fe 0 @WO3-3, porphyrin, Fe 0 The mass ratio of WO3 is 0.2g:0.184g:1g.

[0056] Example 4

[0057] Preparation of porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0058] The preparation method is as follows:

[0059] Step (1): 1.0 g of WO3 powder was dissolved in 200 mL of deionized water, purged with nitrogen for 30 min to remove dissolved oxygen, and ultrasonically dispersed for 1 h to ensure that the oxidized WO3 was fully dispersed in the solution to form a uniform WO3 dispersion A;

[0060] Step (2): dissolving 0.1 g of bis(tetrakis-p-chlorophenyl)iron porphyrin in 50 mL of ethanol and stirring the mixture to form porphyrin solution B;

[0061] Step (3): under stirring conditions, slowly dropwise add the porphyrin solution B to the WO3 dispersion A, ultrasonically disperse for 30 min, and then stir at a speed of 150 r / min for 3 h to form a porphyrin-loaded WO3 solution C;

[0062] Step (4): adding about 1.0 g of ferrous sulfate to the porphyrin-loaded WO3 solution C, and then stirring at a speed of 200 r / min for 1 h to ensure that the iron salt is fully dissolved, to obtain a mixed solution D;

[0063] Step (5): 1.0 g of sodium borohydride was slowly added to the mixed solution D, and then stirred at a speed of 250 r / min for 2 h to deposit Fe 0 The particles are loaded with porphyrin on the surface of WO3, and finally centrifuged. The precipitate obtained by centrifugation is washed with deionized water, dried in a vacuum drying oven at 60°C, and then ground to obtain a composite material of porphyrin and zero-valent iron loaded with tungsten trioxide. Labeled as Por-Fe 0 @WO3-4, porphyrin, Fe 0 The mass ratio of WO3 is 0.1g:0.368g:1g.

[0064] Example 5

[0065] Preparation of porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0066] The preparation method is as follows:

[0067] Step (1): 1 g of WO3 powder was dissolved in 200 mL of deionized water, purged with nitrogen for 30 min to remove dissolved oxygen, and ultrasonically dispersed for 1 h to ensure that the oxidized WO3 was fully dispersed in the solution to form a uniform WO3 dispersion A;

[0068] Step (2): dissolving 0.1 g of bis(tetrakis-p-chlorophenyl)iron porphyrin in 150 mL of ethanol and stirring the mixture to form porphyrin solution B;

[0069] Step (3): under stirring conditions, slowly dropwise add the porphyrin solution B to the WO3 dispersion A, ultrasonically disperse for 30 min, and then stir at a speed of 150 r / min for 3 h to form a porphyrin-loaded WO3 solution C;

[0070] Step (4): adding about 1.5 g of ferrous sulfate to the porphyrin-loaded WO3 solution C, and then stirring at a speed of 200 r / min for 1 h to ensure that the iron salt is fully dissolved, to obtain a mixed solution D;

[0071] Step (5): 1.5 g of sodium borohydride was slowly added to the mixed solution D, and then stirred at a speed of 250 r / min for 2 h to deposit Fe 0 The particles are loaded with porphyrin on the surface of WO3, and finally centrifuged. The precipitate obtained by centrifugation is washed with deionized water, dried in a vacuum drying oven at 60°C, and then ground to obtain a composite material of porphyrin and zero-valent iron loaded with tungsten trioxide. Labeled as Por-Fe 0 @WO3-5, porphyrin, Fe 0 The mass ratio of WO3 is 0.1g:0.552g:1g.

[0072] Comparative Example 1

[0073] In this comparative example, the material was prepared in the same manner as in Example 4, except that the porphyrin loading was omitted, that is, steps (2) and (3) were omitted, and in step (4), the porphyrin-loaded WO3 solution C was directly replaced by WO3 dispersion A. The obtained material was labeled as Fe 0 @WO3.

[0074] Comparative Example 2

[0075] In this comparative example, the material was prepared according to the same method as in Example 4, except that the loading of zero-valent iron was omitted, that is, step (4) and the addition of sodium borohydride were omitted, and in step (5), the porphyrin-loaded WO3 solution C was directly centrifuged to obtain a material labeled Por@WO3.

[0076] Structural Characterization and Analysis of Porphyrin and Zero-Valent Iron Co-loaded Tungsten Trioxide Composites

[0077] Figure 1 Por-Fe prepared in Example 4 0@WO3-4 transmission electron microscope (TEM). It can be seen that Fe 0 The particles appear in the form of darker small particles and are evenly distributed on the surface of WO3. 0 The density of the porphyrin is higher, and it usually shows higher contrast in TEM images, showing darker particles, indicating that it is successfully loaded. Porphyrin is a class of organic molecules with lighter atoms (such as carbon, hydrogen, nitrogen, etc.) that do not have high electron density like metals or metal oxides. Therefore, porphyrin does not show the same dark color as Fe in TEM images. 0 Or the obvious contrast like WO3.

[0078] Figure 2 Por-Fe prepared in Example 4 0 @WO3-4 X-ray diffraction spectrum (XRD). It can be seen that Por-Fe 0 The main components of @WO3-4 include WO3, Fe 0 and porphyrin. At about 2θ 23°, 24°, 26°, 34°, 42°, 49° and other positions, there are multiple clear and sharp peaks, indicating that WO3 exists in the form of high crystallinity. At about 44.6° of 2θ, Fe 0 The characteristic peaks of porphyrin appear at approximately 10° 2θ, indicating that the material is successfully loaded with metallic iron particles, which plays an important role in the material's redox reaction and phosphate removal. The characteristic peaks of porphyrin appear as broad peaks at approximately 10° 2θ, indicating that it exists in an amorphous state or molecularly adsorbed form.

[0079] Experimental study on phosphorus removal from water using porphyrin and zero-valent iron co-loaded tungsten trioxide composite material

[0080] 1. Phosphate removal test of single phosphate body

[0081] Test method: 0.03 g of material sample was added to a conical flask containing 100 mL of aqueous solution (containing only 10 mg / L NaH2PO4 as the solute). The pH of the solution was adjusted to 7.0 with 0.1 mmol / L sodium hydroxide and / or hydrochloric acid solution. The conical flask was then placed in a thermostatic oscillator set at 25°C and 150 rpm. Samples were removed and filtered at various time points (5, 15, 30, 45, and 60 minutes), and the supernatant was collected. The residual phosphate concentration was determined using a UV-visible spectrophotometer. The effluent quality is shown in Table 1.

[0082] Table 1

[0083] Composite materials Initial total phosphorus concentration Total phosphorus concentration after 60 minutes Total phosphorus removal rate <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-1]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 1.4mg / L 86％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-2]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 2.6mg / L 74％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-3]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 1.9mg / L 81％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-4]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 0.1mg / L 99％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-5]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 0.5mg / L 95％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 3.5mg / L 65％ <![CDATA[Por@WO3]]> 10mg / L 6.2mg / L 38％

[0084] Test conclusion: Por-Fe prepared in Example 4 0@WO3-4 has the best phosphorus removal efficiency, indicating that Por-Fe 0 @In WO3-4, the amount of Fe 0 and the amount of porphyrin are in the best ratio, which neither causes the self-catalytic reaction of Fe 0 nor introduces too many side reactions, while maintaining the highest phosphorus removal efficiency.

[0085] The Por-Fe prepared in Example 1 0 @The phosphorus removal rate of WO3-1 is 86%. Compared with Por-Fe 0 @WO3-4, the content of Fe 0 is lower, resulting in a relatively slow chemical reaction and thus reducing the phosphorus removal efficiency. The Por-Fe prepared in Example 2 0 @WO3-2 has the lowest phosphorus removal rate, only 74%. WO3 mainly captures phosphate ions in the solution through physical adsorption, while Fe 0 mainly converts phosphate into insoluble iron phosphate precipitate through chemical reactions. When the content of WO3 increases, the adsorption effect dominates, while the proportion of chemical reactions relatively decreases. This imbalance between adsorption and reaction ratios leads to a decrease in phosphorus removal efficiency. The Por-Fe prepared in Example 3 0 @WO3-3 has a phosphorus removal rate of 81%. Although the amount of porphyrin has increased, the amount of Fe 0 is still relatively low, resulting in the incomplete exertion of its catalytic effect and the limitation of the chemical phosphorus removal efficiency. In addition, iron porphyrin is a complex organometallic complex that can interact with the surface of Fe 0 and thus affect the reactivity of Fe 0 . When the amount of iron porphyrin is excessive, it may overly cover the surface of Fe 0 and reduce the direct contact area between Fe 0 and phosphate. This over-coverage effect will hinder the reaction between Fe 0 and phosphate, thus reducing the chemical phosphorus removal efficiency. It can be seen that Fe 0 plays a key role in phosphorus removal. By continuing to increase the content of Fe 0 , the Por-Fe 0 @WO3-5 composite material was prepared in Example 5, but the phosphorus removal rate decreased compared with Por-Fe 0 @WO3-4. This is mainly because the phosphorus removal reaction occurs at the solid-liquid interface of Fe 0 . When the amount of Fe 0 is excessive, the reaction sites on the solid-liquid interface may reach a saturated state. At this time, increasing the amount of Fe 0 will not effectively increase the active surface area because the reaction rate is limited by the phosphate concentration and diffusion rate on the interface. In addition, at high concentrations of Fe 0In the presence of Fe 0 Not only does it react with phosphate, but it also reacts with the generated Fe 2+ Autocatalytic reactions occur, generating byproducts such as magnetite (Fe3O4). These side reactions consume Fe 0 , and reduces its direct reaction with phosphate, thereby reducing the overall phosphorus removal efficiency.

[0086] The above data show that Fe 0 The optimal ratio of Por-Fe to porphyrin is crucial for phosphorus removal efficiency. 0 The high efficiency of @WO3-4 (99% removal rate) shows that the appropriate amount of Fe 0 Combining the appropriate porphyrin can provide the best chemical reaction efficiency and phosphorus removal effect. 0 When the content is low (such as Por-Fe 0 @WO3-1, Por-Fe 0 @WO3-3), the chemical reaction is not sufficient, resulting in a decrease in phosphorus removal efficiency; when the WO3 content is high (such as Por-Fe 0 @WO3-2), although the adsorption effect is enhanced, the reaction is not sufficient, resulting in the lowest phosphorus removal rate. On the contrary, when Fe 0 Excessive (such as Por-Fe 0 @WO3-5), the phosphorus removal efficiency is slightly reduced due to adsorption site saturation or autocatalytic effect.

[0087] Fe of Comparative Example 1 0 @WO3 (without porphyrin loading) total phosphorus removal rate is 65%, significantly lower than Por-Fe 0 @WO3-4. This is due to the lack of porphyrin, which reduces the electron transfer efficiency of the composite material and leads to Fe 0 The oxidation efficiency of Fe 2+ and Fe 3+ The generation of Fe is insufficient, which reduces the reaction rate with phosphate and the removal effect of phosphate. The total phosphorus removal rate of Por@WO3 in comparative example 2 (omitting the zero-valent iron load) is only 38%, the lowest among all samples. 0 After that, no iron phosphate precipitation was generated in the system, and the removal of phosphate depended solely on the adsorption of porphyrin and WO3, which indicated that Fe 0 The above results show that porphyrin and Fe 0 It plays an important role in the phosphorus removal process. Porphyrin enhances the Fe 2+ and Fe 3+ The formation of Fe 0 Ensure that Fe in the system 2+ and Fe 3+ Source.

[0088] 2. Phosphorus removal test in water in the presence of competitive ions

[0089] Test method: 0.03 g of material sample was added to a conical flask containing 100 mL of aqueous solution sample (solute containing 10 mg / L NaH2PO4, 10 mg / L Na2SO4, 10 mg / L NaCl, and 10 mg / L NaNO3). The pH value of the solution was adjusted to 7.0 with 0.1 mmol / L sodium hydroxide and / or hydrochloric acid solution. The conical flask was then placed in a thermostatic oscillator set at 25°C and an oscillation rate of 150 rpm. At different time points (5, 15, 30, 45, and 60 minutes), samples were taken and filtered, and the supernatant was collected. The residual phosphate concentration was determined using a UV-visible spectrophotometer. The effluent quality is shown in Table 2.

[0090] Table 2

[0091] Composite materials Initial total phosphorus concentration Total phosphorus concentration after 60 minutes Total phosphorus removal rate <h2 style=";text-align:left;direction:ltr"><![CDATA[Por-Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3-4]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 0.3mg / L 97％ <h2 style=";text-align:left;direction:ltr"><![CDATA[Fe <h2 style=";text-align:left;direction:ltr"> 0 <h2 style=";text-align:left;direction:ltr"> @WO3]]><h2 style=";text-align:left;direction:ltr"> 10mg / L 6.0mg / L 40％ <![CDATA[Por@WO3]]> 10mg / L 6.3mg / L 37％

[0092] It can be seen that Por-Fe 0 @WO3-4 still has a very efficient phosphate removal ability in the presence of competing ions. By comparison with the comparative example, due to the lack of porphyrin, the total phosphorus removal rate of comparative example 1 decreased from 65% to 40%, while the removal rate of comparative example 2 did not change significantly. This shows that porphyrin plays a key role in the selective adsorption of phosphate. Although the material lacking porphyrin still has a certain removal effect, it is greatly affected by competitive ions due to its poor selectivity.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a composite material of porphyrin and zero-valent iron co-loaded with tungsten trioxide, characterized in that: The following steps are involved: (1) WO3 powder was added to deionized water, which was then purged with nitrogen to remove dissolved oxygen, and then subjected to ultrasonic dispersion treatment to obtain WO3 dispersion A; (2) dissolving porphyrin in an organic solvent to obtain a porphyrin solution B; (3) adding the porphyrin solution B to the WO3 dispersion A under stirring conditions, then performing ultrasonic dispersion treatment, and then stirring to obtain a porphyrin-loaded WO3 solution C; (4) adding iron salt to the porphyrin-loaded WO3 solution C, and then stirring to obtain a mixed solution D; (5) Adding a reducing agent to the mixed solution D, stirring the solution, and then centrifuging the solution. Washing, drying, and grinding the precipitate obtained by centrifugation to obtain the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material.

2. The method for preparing the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material according to claim 1, wherein: In step (1), the material-liquid ratio of the WO3 powder to deionized water is 0.5-3 g: 100-500 mL.

3. The method for preparing the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material according to claim 1, wherein: In step (2), the organic solvent is any one of ethanol, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide or tetrahydrofuran, or a mixture of two or more thereof in any proportion; the porphyrin is any one of iron porphyrin, zinc porphyrin, cobalt porphyrin or nickel porphyrin, or a mixture of two or more thereof in any proportion, and the solid-liquid ratio of the porphyrin to the organic solvent is 0.05-2 g:50-500 mL.

4. The method for preparing the composite material of porphyrin and zero-valent iron co-loaded with tungsten trioxide according to claim 1, wherein: In step (3), the dosage ratio of the WO3 dispersion A and the porphyrin solution B is: based on the porphyrin and WO3 powder contained, the mass ratio of porphyrin to WO3 powder is 0.1-0.2:1-1.

5.

5. The method for preparing the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material according to claim 1, wherein: In step (4), the iron salt is any one of FeSO4, FeCl3 or Fe(NO3)3, or a mixture of two or more in any proportion, and the dosage ratio of the iron salt and porphyrin-loaded WO3 solution C is: based on the iron element contained and the WO3 powder, the mass ratio of the iron element to the WO3 powder is 0.1-15g:0.5-30g.

6. The method for preparing the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material according to claim 1, wherein: In step (5), the reducing agent is any one of sodium borohydride, potassium borohydride, vitamin C, hydroxylamine hydrochloride, tea polyphenols, and ascorbic acid, or a mixture of two or more thereof in any proportion, and the mass ratio of the reducing agent to the iron salt is 0.1-5 g:0.1-10 g.

7. A porphyrin and zero-valent iron co-loaded tungsten trioxide composite material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.

8. Use of the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material as claimed in claim 7 in phosphorus removal from water.

9. A method for removing phosphate from water, characterized in that: The method comprises the following steps: adding the porphyrin and zero-valent iron co-loaded tungsten trioxide composite material as claimed in claim 7 into a phosphate-containing water body, and stirring the reaction at room temperature.

10. The method for removing phosphate from water according to claim 9, wherein: The phosphate concentration of the water body is controlled at 0.1-100 mg / L, the dosage of the composite material is 0.1-5.0 g / L, the reaction conditions are pH value 5-10, stirring speed 50-300 r / min, and reaction time 30-120 min.

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