Calcium oxide-iron composite agent for treating phosphorus and fluorine wastewater based on synergistic effect, and preparation method and application thereof

Abstract

The application discloses a kind of calcium oxide-iron composite reagent based on synergistic treatment of phosphorus fluorine wastewater and its preparation method and application, belong to phosphorus fluorine pollution remediation technical field.The calcium oxide-iron composite reagent disclosed in the application uses dispersing agent, calcium oxide combined with iron powder as preparation raw material, calcium oxide will react with phosphate and fluoride ion in wastewater, generate substance insoluble in water, finally removed in the form of precipitate;Iron powder will remove the phosphate and fluoride in wastewater in the form of adsorption, precipitation, coprecipitation;Iron powder and calcium oxide in mixed solution can remove phosphorus fluorine by synergistic effect after compounding;The calcium oxide-iron composite reagent of the application shows excellent removal effect to low phosphorus fluorine and high phosphorus fluorine wastewater, so that the calcium oxide-iron composite reagent has wider use prospect in the treatment of water pollution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of phosphorus and fluorine pollution remediation, and particularly relates to a calcium oxide-iron composite agent for treating phosphorus and fluorine wastewater based on synergistic effect and a preparation method and application thereof. BACKGROUND

[0002] At present, the treatment of phosphorus and fluorine wastewater mainly adopts physical and chemical methods, that is, according to different treatment objects and purposes, step-by-step precipitation, air flotation, filtration, activated carbon adsorption, ion exchange and membrane separation technology and other processes are adopted. Among various processes, the chemical precipitation method is the most widely used. The main principle is to add calcium oxide to wastewater, so that it reacts with dissolved salts in wastewater to generate substances insoluble in water, and finally removed in the form of precipitates.

[0003] At present, researchers have developed various calcium oxide-based patented agents for removing phosphorus and fluorine. For example, the Chinese patent application with the publication number CN111995104A discloses a phosphorus and fluorine removal process for industrial wastewater, which uses calcium oxide and flocculants to remove phosphorus and fluorine in industrial wastewater; the Chinese patent application with the publication number CN107555661A discloses a deep purification method for phosphorus and fluorine coexisting wastewater, which adds calcium chloride on the basis of adding calcium oxide to improve the removal effect of phosphorus and fluorine; the Chinese patent application with the publication number CN115784408A discloses a method for removing phosphorus, fluorine and heavy metals in wastewater by using modified crystal seeds to induce crystallization, which uses calcium oxide and crystal seeds to remove phosphorus and fluorine in wastewater while obtaining recyclable byproducts.

[0004] However, the reaction time required for these agents to remove phosphorus and fluorine has not been significantly shortened, and it takes one hour or even longer for the phosphorus and fluorine in wastewater to reach the discharge standard. At the same time, due to the strong influence of calcium oxide on the pH of water, the pH after treatment can reach 11-12, which is far beyond the national standard of 6-9. Therefore, it is an urgent problem to be solved in the development of calcium oxide-based agents to develop a material that can make the phosphorus and fluorine and pH of wastewater reach the national standard in a short time and be suitable for low and high phosphorus and fluorine wastewater. SUMMARY

[0005] The purpose of the present application is to provide a calcium oxide-iron composite agent for treating phosphorus and fluorine wastewater based on synergistic effect and a preparation method and application thereof, to solve the technical problem of long time and large environmental pollution of the existing phosphorus and fluorine wastewater treatment method.

[0006] In order to achieve the above purpose, the following technical solutions are adopted:

[0007] The present application discloses a preparation method of a calcium oxide-iron composite agent, comprising the following steps:

[0008] The dispersant and calcium oxide are added into water, and a mixed solution is obtained after mixing;

[0009] Iron powder is added into the mixed solution, and a calcium oxide-iron composite agent is obtained after soaking.

[0010] The dosage ratio of the iron powder to the mixed solution is (1.5-16.0) g:(3.9-28.5) mL.

[0011] Further, the dispersant is one of trioctyl phosphate, sodium dodecyl sulfate, methyl amyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide, gum and fatty acid polyethylene glycol ester; the purity of the calcium oxide is 85%-95%.

[0012] Further, when the dispersant is trioctyl phosphate, methyl amyl alcohol or fatty acid polyethylene glycol ester, the dosage ratio of the dispersant, the calcium oxide and water is (5.0-20.0) mL:(8.0-19.9) g:(30-70) mL.

[0013] Further, when the dispersant is sodium dodecyl sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide or gum, the dosage ratio of the dispersant, the calcium oxide and water is (1.8-10.3) g:(10.0-25.0) g:(30-70) mL.

[0014] Further, the iron powder is subjected to ball milling treatment and sieving before being added into the mixed solution; the rotating speed of the ball milling is 200-350 r / min, the ball milling time is 0.5-2.5 h; the mesh number of the sieving is 200-400 mesh.

[0015] Further, the kind of the iron powder is one of micron iron powder, nano iron powder and iron filings.

[0016] The soaking time is 2 h-1 month.

[0017] The application further discloses a calcium oxide-iron composite agent prepared by the method.

[0018] The application further discloses application of the calcium oxide-iron composite agent in treatment of phosphorus-fluorine wastewater based on synergistic effect, and the calcium oxide-iron composite agent is used in treatment of phosphorus-fluorine wastewater based on synergistic effect, and the treatment includes the following steps: the calcium oxide-iron composite agent is put into the phosphorus-fluorine wastewater to react, and phosphorus and fluorine in the phosphorus-fluorine wastewater are removed after 40-60 s of reaction.

[0019] Further, the phosphorus concentration in the phosphorus-fluorine wastewater is 1-3000 mg / L, and the fluorine concentration is 1-1000 mg / g.

[0020] Further, the dosage ratio of the calcium oxide-iron composite agent and the phosphorus-fluorine wastewater is (0.3-100) g:(30-1000) mL.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The application discloses a preparation method of a calcium oxide-iron composite agent for treating phosphorus-fluorine wastewater based on synergistic effect, and adopts a dispersing agent, calcium oxide and iron powder as preparation raw materials.

[0023] The application also discloses application of the calcium oxide-iron composite agent prepared by the method in treatment of phosphorus-fluorine wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The application also discloses application of the calcium oxide-iron composite agent prepared by the method in treatment of phosphorus-fluorine wastewater.

[0025] a- Schematic diagram of the calcium-iron oxide composite agent prepared in Examples 1-4; b- Precipitate formed after the reaction of the calcium-iron oxide composite agent;

[0026] Figure 2 a- Schematic diagram of the calcium-iron oxide composite agent prepared in Examples 1-4; b- Precipitate formed after the reaction of the calcium-iron oxide composite agent;

[0027] Figure 3 a- Schematic diagram of the calcium-iron oxide composite agent prepared in Examples 1-4; b- Precipitate formed after the reaction of the calcium-iron oxide composite agent;

[0028] Figure 4 a- Schematic diagram of the calcium-iron oxide composite agent prepared in Examples 1-4; b- Precipitate formed after the reaction of the calcium-iron oxide composite agent;

[0029] a- Schematic diagram of the calcium-iron oxide composite agent prepared in Examples 1-4; b- Precipitate formed after the reaction of the calcium-iron oxide composite agent; DETAILED DESCRIPTION

[0030] For those skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0031] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0032] Herein, all features defined in the form of numerical ranges or percentage ranges, such as values, amounts, contents and concentrations, are for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0033] Herein, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0034] Herein, all possible combinations of the various technical features in the various embodiments or examples are not described in order to make the description concise. Therefore, as long as there is no contradiction in the combination of the technical features, the technical features in the various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered as falling within the scope of the present specification.

[0035] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that after reading the content of the present application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope of the appended claims.

[0036] The following examples use the apparatuses and devices that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are usually carried out according to the conventional conditions, or according to the conditions suggested by the manufacturers. The following examples use various raw materials, unless otherwise specified, and the conventional commercially available products are used, and the specifications are conventional specifications in the art. In the specification of the present application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0037] Example 1

[0038] A preparation method of a calcium oxide-iron composite agent for treating phosphorus-fluorine wastewater based on synergistic effect, comprising the following steps:

[0039] Step 1: At room temperature and normal pressure, 5.0 mL of trioctyl phosphate and 8.0 g of calcium oxide were added to a beaker containing 30 mL of deionized water, and stirred to mix uniformly to obtain a mixed solution;

[0040] Step 2: 5.0 g of micron iron powder was ground at a ball milling speed of 200 r / min for 0.5 h, and sieved with a 200 mesh sieve, then 1.5 g of the ground iron powder was weighed and added to 3.9 mL of the mixed solution obtained in step 1, and stirred uniformly, and soaked for 2 h to obtain a calcium oxide-iron composite agent.

[0041] Example 2

[0042] A preparation method of a calcium oxide-iron composite agent for treating phosphorus-fluorine wastewater based on synergistic effect, comprising the following steps:

[0043] Step 1: At room temperature and normal pressure, 18.0 mL of trioctyl phosphate and 15.0 g of calcium oxide were added to a beaker containing 50 mL of deionized water, and stirred to mix uniformly to obtain a mixed solution;

[0044] Step 2: Take 10.0 g of micron iron powder and grind it at a ball milling speed of 200 r / min for 2.0 h, and sieve it with a 300-mesh sieve, then weigh 8.5 g of the ground iron powder, add it into 17.6 mL of the mixed solution obtained in Step 1, stir it evenly, and soak it for 2 days to obtain the calcium oxide-iron composite reagent.

[0045] Example 3

[0046] A preparation method of a calcium oxide-iron composite reagent for treating phosphorus and fluorine wastewater based on synergistic effect, comprising the following steps:

[0047] Step 1: At normal temperature and pressure, add 1.8 g of sodium dodecyl sulfate and 10.0 g of calcium oxide into a beaker containing 30 mL of deionized water, stir to mix them evenly, and obtain a mixed solution;

[0048] Step 2: Take 5.0 g of iron filings and grind it at a ball milling speed of 200 r / min for 0.5 h, and sieve it with a 200-mesh sieve, then weigh 1.5 g of the ground iron powder, add it into 3.9 mL of the mixed solution obtained in Step 1, stir it evenly, and soak it for 2 h to obtain the calcium oxide-iron composite reagent.

[0049] Example 4

[0050] A preparation method of a calcium oxide-iron composite reagent for treating phosphorus and fluorine wastewater based on synergistic effect, comprising the following steps:

[0051] Step 1: At normal temperature and pressure, add 7.0 g of sodium dodecyl sulfate and 16.0 g of calcium oxide into a beaker containing 50 mL of deionized water, stir to mix them evenly, and obtain a mixed solution;

[0052] Step 2: Take 7.5 g of iron filings and grind it at a ball milling speed of 300 r / min for 1.0 h, and sieve it with a 250-mesh sieve, then weigh 4.3 g of the ground iron powder, add it into 8.1 mL of the mixed solution obtained in Step 1, stir it evenly, and soak it for 20 days to obtain the calcium oxide-iron composite reagent.

[0053] Example 5

[0054] A preparation method of a calcium oxide-iron composite reagent for treating phosphorus and fluorine wastewater based on synergistic effect, comprising the following steps:

[0055] Step 1: At normal temperature and pressure, add 20.0 mL of tricaprylyl phosphate and 19.9 g of calcium oxide into a beaker containing 70 mL of deionized water, stir to mix them evenly, and obtain a mixed solution;

[0056] Step 2: Take 20.0 g of micron iron powder and grind for 2.5 h at a ball milling speed of 350 r / min, and sieve with a 400-mesh sieve, then weigh 16.0 g of the ground iron powder, add it into 28.5 mL of the mixed solution obtained in step 1, stir uniformly, and soak for 1 month to obtain the calcium oxide-iron composite reagent.

[0057] Example 6

[0058] A preparation method of a calcium oxide-iron composite reagent for treating phosphorus and fluorine wastewater based on synergistic effect, comprising the following steps:

[0059] Step 1: At normal temperature and pressure, 10.3 g of sodium dodecyl sulfate and 25.0 g of calcium oxide are added into a beaker containing 70 mL of deionized water, and stirred to mix uniformly to obtain a mixed solution;

[0060] Step 2: Take 20.0 g of iron filings and grind for 2.5 h at a ball milling speed of 350 r / min, and sieve with a 400-mesh sieve, then weigh 16.0 g of the ground iron powder, add it into 28.5 mL of the mixed solution obtained in step 1, stir uniformly, and soak for 1 month to obtain the calcium oxide-iron composite reagent.

[0061] Comparative Example 1

[0062] A calcium oxide reagent, the preparation method of which is carried out according to the preparation method of the calcium oxide-iron composite reagent in Examples 1-4, but without adding a dispersant and iron powder.

[0063] Figure 1 A schematic diagram of the calcium oxide-iron composite reagent prepared in Examples 1-4 before and after reaction, Figure 1 -a is a photograph of the calcium oxide-iron composite reagent, which is a grayish white liquid structure. After the dissolution of calcium oxide, it appears as a milky white liquid, and then black iron oxide particles are added, and finally the composite material exhibits a grayish white liquid structure. Figure 1 -b is the precipitate obtained after filtering the calcium oxide-iron composite reagent after reaction, which is a grayish white powder structure. The precipitate of phosphate and fluoride ions and calcium ions exists as white powder or crystal, and a small amount of iron oxide precipitates as gray-black particles, so that the precipitate after reaction forms a grayish white powder.

[0064] Application Example 1

[0065] 8 g of the material prepared in Example 1-Example 4 and Comparative Example 1 was added into 100 mL of phosphorus-fluorine wastewater with phosphorus concentration of 1, 750, 1500, 2250 and 3000 mg / L and fluorine concentration of 1, 300, 600 and 1000 mg / L respectively, and stirred at room temperature. The sample was taken after 60 s of reaction by filtration. The phosphorus concentration was measured by HJ671-2013 Water Quality-Determination of Total Phosphorus-Flow Injection-Ammonium Molybdate Spectrophotometry, the fluorine concentration was detected by GB / T7484-1987 Water Quality-Determination of Fluoride-Ion Selective Electrode Method, and the pH was measured by HJ1147-2020 Water Quality-Determination of pH Value-Electrode Method. The experimental results are shown in Table 1. Figures 2-4

[0066] From Figure 2 and Figure 3 it can be obtained that the removal rates of the calcium-iron composite agent to phosphorus and fluorine in the simulated phosphorus-fluorine wastewater with initial phosphorus concentration of 1 mg / L and fluorine concentration of 1 mg / L can reach 100% within 60 s. When the initial concentration of phosphorus in the simulated wastewater is increased to 750 mg / L and the initial concentration of fluorine is increased to 300 mg / L, the removal rates of the material to them within 60 s are also 100%. Even if the initial phosphorus concentration is 3000 mg / L and the initial fluorine concentration is 1000 mg / L, the removal rates of the material to them within 60 s are 99.9% and 99.0% respectively. In the whole reaction, the phosphorus concentration of the treated wastewater is reduced to below 0.5 mg / L and the fluorine concentration is reduced to below 10 mg / L, as shown in Table 1, and the pH is maintained between 6 and 9 during the whole process, meeting the national discharge standard. Moreover, compared with the pure calcium oxide agent, the material has higher removal rate to phosphorus-fluorine and smaller influence on the pH of water body. Figure 4

[0067] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.​​

Claims

1. The application of a calcium oxide-iron composite agent in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, When the calcium oxide-iron composite agent is used to treat phosphorus and fluoride wastewater based on synergistic effect, the following steps are included: the calcium oxide-iron composite agent is added to the phosphorus and fluoride wastewater for reaction, and the reaction is carried out for 40-60 seconds to remove phosphorus and fluoride from the phosphorus and fluoride wastewater; throughout the reaction process, the pH is maintained between 6 and 9. The preparation method of the calcium oxide-iron composite agent includes the following steps: The dispersant and calcium oxide are added to water and mixed to obtain a mixed solution; Iron powder was added to the mixed solution, and after soaking, a calcium oxide-iron composite agent was obtained. The ratio of iron powder to mixed solution is (1.5-16.0) g : (3.9-28.5) mL.

2. The application of the calcium oxide-iron composite agent according to claim 1 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, The dispersant is one of the following: trioctyl phosphate, sodium lauryl sulfate, methyl pentanol, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide, glucon, and fatty acid polyethylene glycol ester; the purity of the calcium oxide is 85%-95%.

3. The application of the calcium oxide-iron composite agent according to claim 2 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, When the dispersant is trioctyl phosphate, methyl pentanol or fatty acid polyethylene glycol ester, the ratio of dispersant, calcium oxide and water is (5.0-20.0) mL : (8.0-19.9) g : (30-70) mL.

4. The application of the calcium oxide-iron composite agent according to claim 2 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, When the dispersant is sodium dodecyl sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide or glucon, the ratio of dispersant, calcium oxide and water is (1.8-10.3) g : (10.0-25.0) g : (30-70) mL.

5. The application of the calcium oxide-iron composite agent according to claim 1 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, The iron powder is ball-milled and sieved before being added to the mixed solution; the ball milling speed is 200-350 r / min, the ball milling time is 0.5-2.5h, and the sieve mesh size is 200-400 mesh.

6. The application of the calcium oxide-iron composite agent according to claim 1 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, The type of iron powder is one of micron iron powder, nano iron powder, and iron filings; The soaking time is from 2 hours to 1 month.

7. The application of the calcium oxide-iron composite agent according to claim 1 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, The phosphorus concentration in the phosphorus and fluoride wastewater is 1-3000 mg / L, and the fluoride concentration is 1-1000 mg / g.

8. The application of the calcium oxide-iron composite agent according to claim 1 in the synergistic treatment of phosphorus and fluoride wastewater, characterized in that, The dosage ratio of the calcium oxide-iron composite agent to the phosphorus and fluorine wastewater is (0.3-100) g : (30-1000) mL.

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